Green Technologies & Terminology
This glossary is geared toward projects in the Midwestern US. Many green-building technologies and best practices are region specific - due to climatic differences, availability of materials, or other local conditions. But most technologies can be effectively applied irrespective of the architectural style of the building; given a healthy measure of knowledge and creativity.
Comparing green-building decisions can be difficult, particularly when you add in the life-cycle replacement costs, hidden costs, and other factors. Please contact us if you have questions or want to talk about your green-building project. You also should refer to your medical resources if you have any questions about medical issues.
LAST UPDATE: July 2007. Copyright 2007 © Sage Commercial & Sage Homebuilders -- Fair use permitted providing user credits source.
Absorptive cooling
An advanced cooling system that uses natural gas instead of electricity to drive the refrigerant cycle. The reduced electrical load during peak cooling times of the day reduces demand charges from the utility and reduces reliance on the utility grid. Hybrid systems can use either a conventional electrical compressor or a natural-gas-fired, engine-driven compressor.
There are several efficiency levels of absorptive chillers, measured as COP or Coefficient of Performance – the refrigerant effect output divided by the heat input. “Single-effect” units have efficiencies of 60% to 80%, and often use industrial waste heat as their energy source. “Double-effect” units can have a COP of 1.0.
This technology also has other benefits: no CFC refrigerants, low maintenance, and low repair costs. The technology is not, however, as well developed or field proven as conventional electrical compressors. Absorptive cooling systems range in size from 3ton to 1700 ton capacity. (see Ton or BTU)
Active solar air heating or water heating
Heat from the sun is absorbed by collectors and transferred by pumps (if liquid media) or fans (if air media) to to the house interior, or some type of storage unit, or to a heat exchanger and water heater. Requires COTS electronic controls. Used often for heating swimming pools, but otherwise not widely used in the Midwest.
Air filtration
This can be accomplished through mechanical equipment or by bringing plants into your building. The appropriate technology or plant depends on the building use, size, and configuration. Mechanical filtration includes: conventional filter racks, activated charcoal, ultraviolet, ozone generators, desiccant systems, and electrostatic precipitators. Each method has parameters and limitations that must be considered for your application. These include cost, capacity, size, and noise.
Plants are great ways to improve indoor air quality and provide a natural setting. Recommendations suggest providing a plant for every 100 square feet of floor area in the building. Some species are better than others, according to NASA research, with palms, ferns, ivy, daisies, lilies, and tall grasses topping the list.
Providing more make-up fresh air also will improve the indoor air quality, provided there are not pollutants or allergens in the outside air.
Air-Source Heat Pump (ASHP)
Residential heating system often used in moderate climates, such as St. Louis, that uses the difference between outdoor and indoor air temperatures to cool and heat your home. They work in cold weather because the outside air is warmer than the refrigerant in the system and causes it to boil into a gas. This gas is then compressed which drives the temperature up to 120 degrees or more. This hot gas transfers heat to your home. On very cold days, electric heating may be required to maintain a comfortable indoor air temperature. High efficiency ASHP’s use less energy than conventional models. See HSPF.
Annual Fuel Utilization Efficiency (AFUE)
Rating and measure of heating equipment efficiency, over the full spectrum of operating conditions and modes - including start-up, cool-down, etc. Higher is better. This number is referenced for both commercial and residential equipment. (see Combustion efficiency, CE) See www.energystar.gov for more information.
Autoclaved Aerated Concrete (AAC)
AAC is a lightweight, pre-cast, building material that is useful for walls and some other applications usually reserved for standard concrete masonry units (CMU’s). AAC provides structure, insulation and fire resistance in a single material. AAC products include blocks, wall panels, floor and roof panels, and lintels.
When AAC blocks are fabricated, added chemicals create hydrogen bubbles in the cement that leave voids in the hardened solid material. It is this fine network of voids that imparts the insulation and lightweight characteristic of AAC blocks.
AAC can be routed, sanded and cut to size on site using standard carbon tip band saws, hand saws and drills. The blocks are light enough to be handled in much larger sizes than CMU’s. Most projects built with AAC use thin-set mortar instead of typical cement mortar. The use of AAC is increasing in the Midwest, and there are plants within 500 miles of St. Louis where AAC blocks are manufactured.
BEES (see Life-Cycle Analysis)
Biodegradable
A material that is capable of decomposing naturally within a short amount of time, usually in the presence of water. The time factor is not standard in any way, and this term is often abused for materials that require years or decades to break down.
British Thermal Unit (BTU)
A measure of energy usually used in HVAC system specifications. (see Energy or Ton)
Brownfields
Abandoned or idled industrial and commercial facilities where expansion or redevelopment is complicated by environmental contamination. In many cases, government incentives may be available for brownfield development. Specific LEED credits also apply.
Building orientation (see Orientation of the building)
Built environment
Refers to human-built structures such as office buildings, homes, etc.
Cellulose insulation with borates
Cellulose insulation is made from recycled newspaper. From the perspective of LEED certification, there are several advantages to using this insulation product. It typically is greater than 80% recycled, it is manufactured within 500 miles of St. Louis, there is almost no waste on the construction site, and there are no VOC’s or other “listed” substances in the product.
The borates provide fire and vermin protection. Most cellulose insulation now uses chemical fire retardants as opposed to natural borates. Individuals with chemical sensitivities may need to avoid cellulose insulation that contains newspaper ink, because it can cause allergic reactions. To meet that need, there are some cellulose insulation products made without inked newspaper.
Cementitious foam insulation
A magnesium-oxide based material blown with air to create an inert, effective insulation. It is especially good for people with chemical sensitivities, although it is not widely used in the Midwest.
Certified forest product (see Forestry Stewardship Council)
Chain-of-custody
Documentation that follows a product from the extraction of its raw materials, through production, all the way to its distribution and sale. Usually associated with lumber from FSC or environmental samples.
Charrette
A meeting among the project team conducted during the Planning and Conceptual Design process. Team members exchange ideas with the objective of developing creative solutions to meet green goals. Typically chaired by the Architect or LEED consultant, and included in their scope of work.
Clean energy
Energy produced from biomass, wind, solar, water, or nuclear power. Energy can be extracted from almost any difference in temperature, pressure, or chemical content. Some of these are commercially viable, and are either implemented by utilities to supply the grid, or by end users to meet their specific needs.
The goal of clean energy is to have a low environmental impact, with low or zero emissions, and a minimal impact on the physical surroundings. Hydropower and nuclear power both are more controversial than the other sources, although advances in technology are improving these techniques and helping minimize risks. Waste-burning and wood-burning plants that capture emissions can be clean energy generators. Typical fossil fuel power plants do not provide clean energy because of their emissions and environmental impacts.
End users that generate their own power now can sell this power back to the utility company in Missouri, thanks to "net metering" legislation passed in 2007. In some locales, it is possible to buy "clean" power from the utility company, satisfying LEED credits, but not yet in the St. Louis area.
Combustion efficiency (CE)
Efficiency measure of a heating system under steady-state conditions. Usually applied to hot water heaters or boilers. Higher numbers are better, although this number usually is referenced only for larger heating components. (see AFUE)
Hot-water boilers:
Standard efficiency = 80% CE
High efficiency oil/gas units = 84% to 87% CE
Condensing propane/natural gas units = 88% to 96% CE
Steam boilers:
Standard efficiency = 80% CE
High efficiency oil/gas units = 82% to 84% CE
Commercial Off The Shelf (COTS)
A piece of equipment, component, material, or system that can be purchased directly from a store or distributor. It is commercially available without special preparation or fabrication. Usually COTS items are lower in cost than custom-made items.
Compact fluorescent lamp (CFL)
Compact Fluorescent Lamps (CFL’s) use only about 25% of the energy and reportedly last up to 10 times longer than incandescent lamps. CFL's have that characteristic "pigtail" spiral shape, although new products are available with rounded outer globes that look like incandescent bulbs. There also are different watt ratings and "colors" of light that closely resemble incandescent bulbs and sunlight. (see Full spectrum lighting)
Composite plastic lumber
Lumber made from recycled plastic, used for decking, siding, trim, and other non-structural applications. Benefits include reduced maintenance, increased longevity, increased slip resistance. There are problems with these materials, such as ultimate disposal of the materials used in their manufacture.
Concentrating Solar Power (CSP)
These devices focus or concentrate the sunlight to “harvest” the thermal energy of the sun to drive a generator or heat engine. They do so by means of lenses or more commonly mirrors arranged in a dish, trough or tower configuration. This is a very promising technology for larger-scale power generation. CSP is not currently being tested or used in St. Louis, but there are some commercial applications and testbeds in the Southwest US.
Cradle-to-cradle
A quantitative measure of the impact of materials on the planet. Materials can achieve certification, similar to LEED criteria, based on how well they satisfy the cradle-to-cradle criteria. These include elements of human and environmental health, recycling and recovery, water and energy use (embodied energy) during manufacture, and social responsibility of the manufacturer.
This concept was developed in 1995 by William McDonough and Dr. Michael Braungart, principals of MBDC, a Charlottesville, VA, consulting practice. It is referred to by the acronym – “C2C”. (see Life-Cycle Analysis)
Daylighting
Interior illumination of the building using natural light so that the use of artificial lighting is reduced in the daylight hours, while minimizing glare and excess heat. Common daylighting strategies include orientation and placement of windows, use of light wells, light shafts or tubes, skylights, clerestory windows, light shelves, reflective surfaces, shading, and the use of interior glazing to allow light into adjacent spaces.
Deconstruction
This is an alternative to demolition, and involves taking the building apart and salvaging as much as possible to divert materials from the landfill. Deconstruction can take longer and cost more than demolition, but there are distinct financial incentives that more than offset those factors.
If a property owner deconstructs an existing structure and "donates" the salvaged materials to a nonprofit organization, the owner earns what amounts to an earned-income tax credit - similar to giving a cash donation to a charity. Depending on the owner's tax circumstances, usually the value and corresponding tax effects and savings of disposal costs more than offset the added expense in time and labor required for the deconstruction.
There are deconstruction options available in St. Louis, but it is essential that the building owner explore these prior to making the decision about whether to deconstruct or demolish. There is some up-front planning required, and some additional paperwork, but the outcome is well worth the effort. The decision to deconstruct instead of demolish also likely will be favorably received by the community, which can be beneficial during zoning or plan-review discussions.
Detention vs retention, stormwater
"Detention" means slowing down the stormwater so it all doesn't run off immediately during a rainfall event.
"Retention" means retaining it on site for a longer or even indefinite time and not allowing runoff at all.
Downcycling
Similar to recycling, except the material that is reused is reused for something less energy intensive than its previous use. For instance, plastic bottles being downcycled into composite lumber. Even though most downcycled materials cannot be reused themselves, at least the process keeps these materials out of a landfill for a longer time.
Dust spot efficiency
Test is a semi-quantitative measure of a filter’s collection efficiency for fine airborne particles; specifically those associated with smudging of the interior surfaces of buildings. Upstream and downstream paper target filters collect particles and the change in opacity (light transmission) of the filter is measured.
Earth-sheltered design
A structure designed and built partially below ground, either by digging into existing ground or by covering over parts of the house with several feet of fill soil. The more constant temperature of the ground improves energy efficiency and reduces environmental impact, but requires additional focus on waterproofing, drainage, and pest control.
Embodied energy
Embodied energy reflects the relative energy and natural resources required to fabricate, transport, and install the building materials and/or components. This is an inexact and somewhat subjective measure. It does not consider material cost, but often cost is reflective of embodied energy. In this case, smaller numbers are more desirable. Some rounded values for embodied energy, in energy per unit mass, are: Concrete (2) Kiln-dried hardwood (2) Clay brick (3) Recycled aluminum (9) Recycled steel (10) Glass (12) Virgin steel (32) Plastics, typical (90) Virgin aluminum (180).
One objective of green building is to use materials with the lowest feasible embodied energy. (see Cradle-to-Cradle)
Energy
Energy is the capacity to do work, and does not have any component of time in the measurement. Energy usually is measured in kW-hr or joules (electrically), Btu or therms (thermally) or even gallons of gasoline or units of fuel (chemically). The unit costs of different forms of delivered energy vary tremendously - with electrical energy being much higher than natural gas, for instance. (see Power)
Energy modeling
A computer model used to analyze a building's energy systems in order to project its possible consumption rate. Many factors are programmed into the model; for example: window specifications and locations, insulation, HVAC specifications, climate, etc. There are several software tools available from government sources (Dept of Energy, EPA, etc), and modeling should be done by a professional consultant with experience germane to the project at hand.
Energy recovery
A process to attain useable energy from a waste stream, either solid, liquid, or gas. For instance, a heat exchanger recovers energy from a building's exhaust air to pre-heat or pre-cool makeup air for the building. Recycling is a type of energy recovery.
Energy recovery ventilator (see Heat recovery systems)
Enthalpy wheel
Mechanical system usually consisting of a rotating, desiccant-coated, wheel apparatus that either pre-heats and humidifies cold, outside make-up air in the winter, or pre-cools and dehumidifies warm, make-up air in the summer. (see Heat recovery systems)
Environmental Life-Cycle Analysis (see Life-Cycle Analysis)
Evaporative cooling
When liquid water evaporates into a gas, it absorbs heat from its surroundings. (This is how sweat cools a person's skin and a car's radiator cools the engine.) This physical phenomena is used in air conditioning systems to cool building air directly or cool refrigerant in a piping system. The effectiveness of evaporation goes up as humidity goes down. Another drawback is that the process requires a continuous stream of water - since water usually is lost to the atmosphere when it evaporates. Evaporative cooling loses some of its effectiveness in the St. Louis summer due to high humidity.
Fly ash
The ash residue from high temperature combustion processes. Electric power plants using western coal produce a non-toxic fly ash with a very high calcium content. It can be a substitute for Portland Cement (the common bonding material in concrete), significantly reducing the embodied energy of the concrete. This product is commercially available in St. Louis and is cost competitive depending on admixtures needed for the application. Fly ash also is used on a limited basis in some "green" bricks and CMU's (traditional concrete blocks).
Forestry Stewardship Council (FSC)
A non-profit organization that certifies lumber and forests that are harvested and managed using responsible and sustainable best practices. FSC forests are not clear cut, for instance, but are selectively culled to support long-term viability to the forest, reduce erosion, and provide wildlife cover. See www.fsc.org.
Formaldehyde
A pungent-smelling, colorless chemical compound occurring both naturally and as a synthesized product. It is produced by fire, engine exhaust, and is formed by sunlight and oxygen combining with atmospheric methane (a component of smog). Industrially is it produced from methyl alcohol, and is used as a disinfectant, preservative, as a component in the synthesis of complex chemical products, and also in fabrication of some building materials such as plywood, OSB, particleboard, carpet, carpet pad, paper products, resins, paints, and insulating foams. (Note: There are types and brands of these products that contain little or no formaldehyde.)
Formaldehyde even in low concentrations can be a respiratory irritant and is classified as a carcinogen. Contact can cause allergic reaction in some people, and burning materials containing formaldehyde can create toxic fumes. Because of its ubiquitous applications in building materials, formaldehyde is one of the more common indoor air pollutants. It can trigger breathing difficulty, cause headaches, and irritate eyes and mucous membranes.
Green buildings strive to minimize or eliminate formaldehyde-based building materials, or at least to use materials that better contain or limit the mobility of the compound. During a fire, however, it is not possible to control the release of formaldehyde.
Full cut-off luminaires
Exterior lamp holders, commonly called "light fixtures", that direct all light down toward the area requiring illumination. Conventional luminaires cast light up and all around, wasting energy and causing localized "light pollution" or unnecessary lightening of the night sky. Since full cut-off luminaires cast light only downward, the lamp sizes can be smaller, reducing energy consumption, and they also enhance safety by eliminating glare for pedestrians and drivers.
Full-spectrum lighting
Natural sunlight has a color spectrum that is different from most artificial light sources. Literally every color of the rainbow is in sunlight, including infrared and ultraviolet. Humans have adapted to "needing" this full spectrum of light, but it is difficult to attain inside a building with artificial lighting.
The appearance of a light source is a combination of "color temperature" and “color rendition”. Full-spectrum lighting should have a color temperature and color rendition as close to natural sunlight as possible. Color temperature of artificial lighting ranges from below 3500o to above 4100o. Lower color temperatures bring out the red and orange while higher color temperatures cast a bluish hue. Natural sunlight varies, but surprisingly has a color temperature of about 5500 o. The reason all colors are bright in sunlight is because sunlight has a Color Rendition Index (CRI) of 100. Most artificial lamps cannot match that number.
Compact fluorescent lamps have a color temperature and CRI that is very close to natural sunlight.
Generator or Genset
A stand-alone power plant producing electricity. It usually consists of a diesel-fired engine coupled to an alternator, connected to a building's electrical distribution system through a transfer switch. The transfer switch, either automatic (ATS) or manual (MTS) ensures the genset will never inadvertently feed power into the grid. A genset for a typical residence could vary from 5kW to 20kW, and is powered by diesel fuel, gasoline, or natural gas, depending on the site constraints.
Geothermal Heating and Cooling
A HVAC system applicable to residential or commercial buildings. Instead of using electric/gas for heat in the winter, and electricity/refrigerant for cooling in the summer, a geothermal system pumps a liquid through holes in the earth to gain (winter) or discharge (summer) heat from/to the building envelope.
A geothermal system is more efficient and quieter than a conventional HVAC system. It uses a heat pump, similar to a typical mechanical heat pump, but rated using different criteria. The holes in the earth can be horizontal or vertical, depending on the space constraints of the site. The key criteria is that the holes be more than 5ft below the surface, since that is where the year-round temperature becomes constant and stable. If vertical, the holes are drilled by a well-drilling company, about 150ft to 200ft down. The larger the building and system, the more holes required.
Like a heat-pump system, if the outside temperature is very hot or very cold, a geothermal system may require an electric heating coil or small conventional air conditioner to augment its operation.
Green building, green-certified building
A green building combines minimized overall environmental impacts with a healthy indoor environment for its occupants. (If done properly, the building does all this at a profit for the owner.) The environmental benefits include reduced energy and water consumption, resource conservation, site preservation/restoration, increased reuse/recycling, and reduced pollution. These goals are accomplished through incorporation of design techniques, construction methodologies, system technologies, and building materials. A "green-certified" building meets established benchmarks for these various qualities and the process is audited by an independent third-party agency. (see High-performance building)
Green Electricity Provider
A utility that generates or invests in electricity from renewable sources, and then sells it for a small premium over standard electricity costs. Typical renewable sources are wind, hydro, landfill gas, and solar, but presently only wind is commercially viable in Missouri. Commercial wind plants perform best in the NW corner of the state due to prevailing winds. Ameren sells credits that are partially invested in these wind plants. You can learn more at http://www.ameren.com/PurePower/.
Green power (see Renewable energy)
Green product / material
This is a subjective definition that can vary greatly. There are some national certification organizations that evaluate many qualities of a material or product before assigning a green rating to them. Most look at the manufacturing process, recycled content, whether the item itself is recyclable, toxicity, biodegradability, and embodied energy. There is compromise in all things, and classification as a green product or material is no different.
Greywater
Water that is "slightly used" (compared to "new" drinking water out of the tap) that can be reused for non-potable purposes. Greywater can be captured rainwater, or depending on local code it also could include drained water from sinks and showers.
After simple particulate filtration, greywater can have several uses. The easy use is irrigation, and the more difficult uses are clothes washing or toilet flushing. The difficulty of reuse is again, based on code, but also is a cost factor. Reusing rainwater for later irrigation is relatively inexpensive - it just requires a cistern for storage and then some way to distribute it to the plants. Using greywater for clothes washing or toilet flushing is more costly, requiring separate distribution piping, valving, and careful labeling to ensure greywater is never mixed with potable drinking water.
Many municipalities have restrictions on how grey water can be used, so check first before installing a storage/reuse system.
Harvested rainwater
The rain that falls on a roof is channeled by gutters and downspouts to a storage tank or "cistern". The uses of this water are dependent on any pollutants that may be picked up from the roof surface or air. Typically used for irrigation, but in many parts of world it is used for drinking. (see Greywater)
Heat island effect (see Urban heat islands)
Heat recovery systems
Mechanical systems that capture waste heat from one system or process and use it to replace heat that would otherwise come from a primary energy source. A heat exchanger is required to transfer the heat from one "medium" to another. This is commonly done in climate-control and hot-water systems.
Heating of make-up air for a commercial building can amount to 15% of the total heating load. (Can be much more for labs or other buildings with higher make-up air requirements.) In the summer, hot outside air adds a similar load to the HVAC system not only from the heat but also from the humidity. An Energy Recovery Ventilator, or ERV, helps modulate temperature and humidity of this make-up air supply. The process provides two primary benefits: reduction of heat load (energy use) of the building; and reduction of humidity below the level where mold and dust mites will readily grow. (see Enthalpy wheel)
Heat transfer
Heat is transferred by three mechanisms: conduction, convection, and radiation. Conduction is what happens when one surface touches another. Convection occurs when airflow over a surface moves heat into or out of a material. Radiation is when heat is transferred from a warm object to a cold object simply by being in the "line of sight". For example, the sun heats the planet, and the planet loses heat to space at night, through radiation. The rate of heat transfer is proportional to the difference in temperature of the two materials, whether they are solid, liquid, or gas.
There – you just saved the cost of a 3 semester hours of college credit.
Heating and Seasonal Performance Factor (HSPF)
Rating of the efficiency of residential heat pumps. Higher is better, with a target being 8.0 or 8.2 for the St. Louis area. See www.energystar.gov for more information.
High-performance building
A building that is energy and water efficient, but not necessarily green. (see Green building)
High-quality duct system
Most conventional, forced-air HVAC ductwork leaks. This results in energy loss when hot or cold air escapes, and can result in health problems caused by mold growth and other contamination.
These problems can be avoided or at least minimized by thorough sealing of the building's ductwork. The ducts are sealed using a fiber-augmented latex mastic and fiberglass tape both inside and outside of the seams. The air handler, support platform and return plenum are sealed air tight at the joints, and duct tape is not used anywhere in the system. Further, ductwork is not run inside of the exterior building envelope walls.
The system can be performance tested to ensure proper installation.
HVAC
An acronym for Heating Ventilation and Air Conditioning. This is the mechanical equipment that controls the temperature, humidity, and air circulation inside a closed building.
Icynene foam insulation
A versatile insulation material that is widely used in residential and small commercial projects. Icynene is a sprayed foam product with an R-value of about 3.5 to 4.5 per inch. This is compared to rock wool (2.2 - 2.9) fiberglass batts (2.9 - 3.8) or polyisocyanurate (5.6 - 7.0).
Impervious surface area
That area of a property where rainwater cannot soak into the ground. Usually includes the building footprint, solid driveways and sidewalks, patios, or outbuildings. Most municipalities have code limitations on how much impervious surface area can be part of a development plan. (see Pervious paving or Stormwater management)
Indigenous Materials
Describes building materials that are produced near the construction site. This reduces transportation costs, energy consumption of transportation, and also helps to boost local economies. The USGBC considers materials that originate closer than 500miles to the project site to be good target sources.
Indoor air quality (see Air filtration)
Insulating Concrete Forms (ICF)
ICF's consist of large, expanded foam blocks with an interior hollow section. Walls are constructed quickly by stacking the foam blocks, placing reinforcing steel bars (rebar) inside the cavity, and pouring concrete into the cavity from above. Once the concrete hardens, the wall is rigid, strong, and very well insulated - a structural concrete core with a layer of rigid foam both inside and outside the concrete. ICF's are an excellent system for walls only, and cannot be used for floors, roofing, or any other orientation that would not lend itself to the stacking and pouring operations.
Insulation (see Icynene, Wood fiber cellulose, R-value)
Integrated Part Load Value (IPLV)
A quantitative measure of the efficiency of commercial HVAC chillers. IPLV is measured as energy per unit of cooling power; usually kW / ton or kW-hr / ton-hr. A lower number means better efficiency. Usually water-cooled chillers are more efficient than air-cooled chillers. Going from lowest to highest, typical values for AIR-cooled chillers are:
0.95 to 1.2 for 1-25 ton with scroll compressor
0.6 to 0.9 for 25-100 ton with screw compressor
0.65 to 0.85 for 25-100 ton evaporative cooled
Typical values for WATER-cooled chillers are:
0.6 to 0.8 for 25-100 ton with screw compressor
0.45 to 0.7 for 25-100 ton with centrifugal compressor
0.35 to 0.6 for 100-3000 ton with centrifugal compressor and VFD's
Inverter
A device that converts direct current (DC) electricity, usually generated by a photovoltaic cell array, to alternating current (AC) useable in the home. An inverter also is a key component of a Variable Frequency Drive, or VFD.
Kilowatt
(kW) A measure of the rate of doing electrical work, or the flow rate of electricity in a wire or device. (compare with Kilowatt-hour). Electrical power is sold in units of kW-hr (not kW), which is a 1kW load running for one hour.
Kilowatt-hour
(kW-hr) A measure of electrical power, work, or total electrical use (compare with Kilowatt). This is equivalent to load of 1,000 Watts running for one hour. This is the unit of power sold by the utility company, and usually is $0.07 to $0.08 per kW-hr in the St. Louis area.
Latent heat load
The heat resulting from having people inside a building, as opposed to lighting, office machines, or other non-living loads. Latent heat is something that must be managed by the HVAC system or natural ventilation processes, and is a result of the inside humidity changes caused by living animals like people. This load impacts the ability of the HVAC to remove humidity from the inside air. (see Sensible heat gain)
LED lighting
LED's are Light Emitting Diodes, and have been a part of consumer electronics for decades. Only recently, applications in lighting have been developed to commercial viability in applications ranging from street intersection signals to building spotlights. LED's are much more efficient than incandescent lamps, but not as efficient as CFL's. LED lights last longer than CFL's, and are ideal for task lighting due to the directional nature of the light. Presently LED's are quite a bit more expensive than other lamps, so the user should carefully consider the life-cycle costs when selecting this option. No doubt the cost will come down over time.
Life-Cycle Analysis (LCA)
The evaluation of a building, system, or material for a green building should take into account much more than simply the monetary cost of the alternative. The strictly monetary evaluation is termed, "Life-Cycle Cost", and is outlined under that definition.
The LCA typically uses a software model to assess both economic and non-monetary impacts. One example is the National Institute of Standards and Technology (NIST) model called BEES, for Building for Environmental and Economic Sustainability. That model combines a Life-Cycle Cost evaluation with consideration of a multitude of environmental factors. The factors are weighted, and a quantitative result is derived. The user defines the weights of each evaluating factor based on project constraints and priorities. (see Cradle-to-cradle)
Life-cycle cost (LCC)
Rather than looking just at the first cost, a Life-Cycle Analysis evaluates all the financial costs of the alternative, whether that alternative is a building, a system within the building, or a material used in the construction. LCA includes the first cost, maintenance, repairs, replacement, and salvage cost. All future costs are estimates, and are discounted to "day one" using an appropriate discount rate. Ideally the financial decision is made in favor of the alternative with the lowest life-cycle cost. Other factors also should be considered, and those are outlined under Environmental Life-Cycle Analysis (LCA).
Low pressure drop high efficiency air filters
Air filters in an HVAC system remove particulates and contaminants from the circulating airflow. Usually greater filtration capacity also means the filters clog faster and decreases cooling capacity of the air-conditioning system. (This isn't as big a factor in the winter with forced-air heating.) Extended surface pleated air filters allow greater air filtration without a significant increase in horsepower requirements or the efficient loss of higher filtration, but they are more costly. (see MERV)
Low-biocide paint
Some paints have fungicides and pesticides added during the manufacturing process to increase shelf life and hinder mold/mildew growth. These chemicals can be respiratory or skin irritants. A low-biocide paint does not include these additives, but may be difficult to find on the shelf at local stores. Call ahead, or special order immediately prior to use (due to shorter shelf life).
Marine Stewardship Council (MSC)
A non-profit organization that certifies fisheries and their food products as being harvested and managed, respectively, by responsible and sustainable practices. Marine food products that earn the MSC label are not over-fished, they are caught using fishing techniques that minimize undesired bycatch, and do not harm the underwater habitat (such as bottom-dragging nets). See www.msc.org, or you can download a “Seafood Card” from the Monterey Bay Aquarium, Seafood Watch site at www.mbayaq.org.
Minimum Efficiency Reporting Value (MERV)
Rating of the particulate removal efficiency of air filters for HVAC equipment. The higher the MERV, the more filtration it provides. MERV can range from 7-8 to as high as 14. A higher MERV is more expensive, and can result in decreased efficiency of the HVAC system. Occupants with allergies or asthma should consider higher MERV ratings.
Net metering
Some renewable energy systems can intermittently generate more power than is needed on the site. The excess energy can be stored onsite, but it is much more financially advantageous to push that power out through the meter and service connection on to the commercial electricity grid. This literally makes the meter turn backwards.
Until 2007, Missouri law allowed customers to return power to the grid only at wholesale rates. But a "net metering" law passed in 2007 required utilities to net out this co-generated power at the same unit rate the customer is paying. For example, if a building uses 2000 kW-hr of power during the workday, and the wind generator or PV array generates 1200 kW-hr during the 24-hour day, the net use and charge is for 800 kW-hr.
Orientation of the building
Building orientation is important to take best advantage of (and minimize problems with) natural sunlight. Ideally a green building admits direct winter sun to provide passive heating, excludes direct summer sun to minimize undesired overheating, and always allows reflected sunlight into the building for natural daylighting of the interior. To make this happen, the building usually will have its major axis oriented within 20o of E-W, providing a major south-facing wall for windows.
Oriented Strand Board (OSB)
OSB is a wood-panel product that is replacing plywood in some building construction applications. OSB is fabricated from resin-adhered wood fibers (instead of intact wood veneers) that are all oriented in the same direction within the board. Hence it can be made from smaller trees, wood fragments, and mill waste. OSB typically is made from fast growing and small-diameter trees. Because of this, OSB is considered a (rapidly renewable" building material. OSB is as strong as plywood and most model building codes allow it as a substitute for plywood.
There are two dominant types of resin used to make OSB and plywood: Phenol Formaldehyde (PF) and Urea Formaldehyde (UF). PF resins are more stable chemically than UF resins. Some industry experts believe OSB made with UF resin can release formaldehyde into the atmosphere – in the factory, at the lumber yard, or when used in a building. Experts disagree, however, on how long after manufacture this chemical release is possible or likely. If concerned about the possibility of formaldehyde release, the safest approach is to use PF-resin OSB. In the field, PF-OSB can be visually recognized by looking for small reddish/brown spots on the wood flakes. This is the cured PF resin.
Passive design, passive solar design
In addition to the concepts outlined in "Passive heating and cooling", passive design also may be considered to include use of natural daylighting to replace artificial lighting.
Passive heating and cooling
Heating and/or cooling is accomplished through natural techniques instead of relying solely on mechanical HVAC equipment. (see HVAC) Can include elements of structural design, building placement, materials selection, vegetation, opening windows, etc; and it affect air circulation, temperature, and humidity of the building's interior spaces. For example, the heat from sunlight or coolness of the night air can be "stored" in massive walls to modulate temperatures. Or placement of windows and hallways can promote natural air flow through the building relying on natural airflow gradients caused by temperature differences. These techniques lower energy usage, reduce noise, and often provide a more comfortable and healthier indoor environment.
Passive solar water heater (see Solar water heater)
Pervious paving, pervious pavers
A paving material and underlying subsurface preparation that allows rainwater to penetrate into the soil below instead of running off into streets and storm drains. Some pervious paving systems can store the water for irrigation, but most simply divert the water from being conveyed in driveways, parking lots, streets, and sewers.
Pervious Paving usually means a concrete that has no sand in the mix. The result is voids throughout the finished slab that allow water to drain right through the concrete. Pervious Pavers are pre-fabricated masonry blocks or bricks that have sand or gravel filler between the pavers instead of mortar. Over time, depending on the design, vegetation may grow between the pavers.
In all cases, there are two key requirements: (1) thorough subsurface preparation; and (2) preventative maintenance. These techniques require more elaborate grading, substrate preparation, and even French drains in some cases. This adds time and money to the preparation work, but ideally this cost is recovered in the less expensive materials and overall life-cycle cost (see LCC). It also is important to maintain these systems on a periodic basis to keep fine particulates (like silt) from clogging the sand/gravel filler. The particulates impair the ability of the gravel to allow water to soak into the soil just like dirt impairs an air filter’s capability. Preventative Maintenance usually means sweeping, vacuuming, or power washing.
Phantom load
This is the electrical load, or power used, by a variety of electrical items when they are plugged in but not performing any function. The load is a phantom, because it is difficult to identify and cure.
For instance, consider those surge-suppressing power strips with the toggle switch and the little red light that allow the user to plug in several other items to one wall outlet. These use between 10W and 20W on their own with nothing plugged into them. That means if you have a desk lamp and USB hub plugged in, but those items are turned off, the power strip is still turning electrical energy into heat at the rate of as much as 1/2 kW-hr per day. The solution in that case, if you really don't need the surge suppression feature (most of them aren't much use anyway) is to use a simple extension cord that adds no load at all.
Some other phantom loads are the multitude of power converters for phones, radios, hair dryers, and other electronics or small appliances. These convert the AC current coming out of the wall into DC current for the device. Most of these use current even when they are turned off. For example, a 1 amp DC output converter for a small desktop radio can use 5-10W of power even when the sound system is turned off. Again, the solution is to turn them off when not in use - which in this case means unplugging them or using a switched AC power source.
Photovoltaic devices or panels (PV's)
PV's are devices that directly convert sunlight to electricity. PV’s can be used to power outdoor signs, lighting, or other circuits where provision of electricity is difficult or costly. Larger PV systems can power entire buildings or even some industrial processes. (see Concentrating Solar Power)
There are presently four different types of PV's available on the commercial market that can perform in local applications. There are pros and cons associated with each technology, and there are some smart consultants and suppliers in St. Louis that can help you pick the best product for your application.
In St. Louis, PV systems generally are not as cost effective as wind generation. In any case, excess power can be stored in a battery storage system or sold back to the utility provider. (see Net metering)
Plug load
An electrical load resulting from something plugged into a receptacle. Usually includes things like photocopying machines, vending machines, desktop computers, and other office machines. Plug load can range from 0.75 W/sf (continuous) to 3 W/sf (peak).
For a 20,000sf office building, that would amount to a minimum of 15kW load throughout the day, or a total of 360 kW-hr of energy for a 24-hour day. At $0.08/kW-hr, that comes to $29/day, or over $10,000 per year! Turning off office machines at the end of the workday, managing vending loads, and reducing plug loads can result in significant savings over time.
Post-consumer recycled content
A measure of how much of a material or finished product results from another material or product that was discarded for disposal or recovery. For example, printer paper that has 10% post-consumer recycled content means 10% of the raw materials used to make the printer paper came from paper recycled from the waste stream. (see Pre-consumer recycled content)
Power
Power is related to Energy, but introduces the measure of time. Power is the amount of energy transferred or used per unit of time. It also is the time rate of doing work. Power is measured in kW, horsepower, or joules/sec (electrically), Btu/hr or therms/hr (thermally). As with all units, there are US and metric measures, and you can find good, free conversion sites on the Internet. (see Energy)
Pre-consumer recycled content
A measure of how much of a material or finished product comes from another material or product that was a process waste stream of an industrial process and never made it into the consumer market. For instance, wood waste from a mill that is used for particle board or OSB could be a pre-consumer recycled material. May also be called post-industrial or secondary material. (see Post-consumer recycled content)
Programmable Logic Controller (see Variable frequency drive)
Rapidly renewable resource
A building material or component used in building materials that is not noticably depleted through its normal use. In other words, the available reserves of the material remain constant or even increase over time. A fast-growing tree used for lumber is an example.
Recyclable Content
Materials that have potential to be recovered from recycling, whether or not the recycling actually occurs.
Recycled Content
Percentage of recycled materials in a product. (see Post-consumer and Pre-consumer recycled content)
Renewable energy
Energy resources that can keep producing indefinitely without being permanently depleted. Examples are wind or solar power, although there are many examples in various stages ranging from bench-scale testing to commercial viability. Petroleum, coal, and natural gas are NOT renewable, because their supply is finite and exhaustible.
Renewable Energy Certificates (REC's)
Also known as green certificates, green tags, or tradable renewable certificates, REC’s represent the environmental attributes of the power produced from renewable energy projects. In other words, REC’s are electronic tracking data created when power is generated through renewable processes – such as solar, wind, biogas, and some hydro processes. The power generator can sell the REC’s to utilities or private companies that want the REC’s as part of their service offerings or business plans.
On a consumer level, REC’s can be sold separate from commodity electricity. Customers can buy green certificates even if there is no access to green power through their local utility or a competitive electricity marketer, such as in St. Louis. (see Green Energy Provider)
Retention, stormwater (See Detention vs retention)
R-value
A measure of the resistance to conductive heat flow of an insulating material, especially insulation. (see Heat transfer) Higher numbers are better, and recommendations change with climate region. Some targets for the St. Louis area are:
- Attic R-49
- Cathedral ceiling R-38
- Wall R-18 to 22
- Crawlspace R-19
- Slab edge R-8
- Basement (exterior) R-10 to 15
Insulation that has an R-value quoted as "R per inch" can be added together to reach the total R-value of the assembly. See www.energystar.gov for more information.
Seasonal Energy Efficiency Ratio (SEER)
Rating of the energy efficiency of a residential electric air conditioning condenser. A higher SEER rating is better, with a SEER-14 being a good target. More efficient units are larger and require more clearance around them to operate correctly. See www.energystar.gov for more information.
Sensible heat gain
The energy load resulting strictly from heat transfer that must be managed by either the HVAC system or natural ventilation. For a typical small commercial or residential building, this amounts to the following.
- Lighting - 41%
- Windows - 32%
- Equipment - 17%
- People - 8%
- Conduction through walls - 2%
These numbers can shed some light on best strategies to reduce sensible heat loads through better design. (see Latent heat load)
Sick Building Syndrome
Since people spend so much time indoors, the indoor environment can have a profound impact, good or bad, on a person's health. One of the biggest adverse impacts comes from airborne substances that become respiratory or skin irritants. These substances often are organic and grow inside the HVAC ductwork, or inside the walls - typically places where humidity and temperature are right for growth. But synthetic compounds also can contribute to Sick Building Syndrome – such as formaldehyde (see Formaldehyde)
Mold is a big culprit in Sick Building Syndrome. Molds have a narrow range of temperature and humidity where they can grow, and when spores are released, they can spread throughout a building through the ventilation system.
The remedies for SBS can range from cleaning ductwork to actually demolishing entire buildings in some cases (believe it or not); depending on the nature and extent of the problem.
One of the big objectives of green buildings is to eliminate Sick Building Syndrome. A healthier indoor environment improves productivity, reduces absenteeism, reduces insurance rates, reduces maintenance costs, and other benefits.
Smart house
Programmable electronic controls (with sensors in various locations) that regulate heating, cooling, ventilation, lighting, and appliance operation for energy conservation purposes. Smart House systems can even be remotely controlled using cell phones or via the Internet.
Smart window (see Solar Heat Gain Coefficient)
Solar Heat Gain Coefficient (SHGC)
A measure of the fraction of heat transmitted through a window plus the fraction absorbed in the glazing and ultimately conducted/convected into the building interior. Higher numbers mean more heat, but higher is not necessarily worse - it depends on the application. SHGC varies from 0.84 for a single pane of clear glass down to 0.0 for insulated spandrel glass.
Conventional glass and assembled windows have a set SHGC that never changes unless a permanent film is applied to the glass. But it is possible, and products are commercially available, to control or vary the SHGC in a specific glazing application. Specifically, there are several manufacturers producing "electrochromic" glass/windows, where the SHGC changes based on the introduction of an electrical voltage. That means when you flip a switch, the window goes from clear to opaque or completely dark. Not quite commercially available yet are "photochromic" (SHGC changes with light level) and "thermochromic (SHGC changes with temperature).
Solar photovoltaics (see Photovoltaic)
Solar water heater
A building system to heat water using sunlight, geothermal energy, or other natural sources. Can include potable use, swimming pools, or industrial process applications If solar energy is used, typically a backup electric or gas water heater is also installed.
The primary benefit is lower energy usage. Heating water accounts for around 8% of total energy in commercial buildings, about 15% in residential applications, and up to 40% for hotels. Passive solar water heating is viable in St. Louis, particularly for heating swimming pool water (low-temperature collectors) or potable drinking water (mid-temperature systems).
There are 4 criteria used for describing solar water heaters:
Passive - relies on natural liquid convection and has no pumps or powered components.
Active - uses mechanical pumps and/or controls to manage the system.
Direct - the potable water is heated directly by the source in the collector.
Indirect - the collector heats some other fluid that in turn transfers heat to the water in a heat exchanger.
Stack effect
As warmer air rises inside a building during cold weather, it causes higher air pressure on the upper floors and lower pressure at the ground levels. This pressure differential results in air being drawn into the building through small cracks and seams as well as through open windows and doors. This airflow will result in energy losses and an uncomfortable indoor environment on the lower floors. (see Passive heating/cooling for contrasting discussion of intentional temperature gradients and airflow)
Stormwater management
Rainfall that lands on a property needs to go somewhere. On unimproved, vacant land, much of the water soaks into the ground, and the rest runs off as surface sheet flow. The more water that doesn't soak into the ground, the worse local flooding will be, and the more overload will be introduced into the stormwater drainage system.
In many parts of St. Louis, the stormwater and sanitary sewer are a combined system, so rainwater ultimately ends up in the MSD wastewater treatment plants. During a prolonged rainfall event, this can result in overflow of the plant and the release of untreated or inadequately treated water into surface streams and rivers. Not only is this damaging to stream/river habitats and a sanitary problem, but it also is a violation of USEPA regulations and can result in lawsuits against MSD.
Maximizing the soaking in (or "infiltration"), or slowing down the runoff of stormwater is a priority of green building. There are many strategies that can be used, from cisterns to capture rainfall from roofs and gutters, to ponds or even underground tanks that detain and release the captured rainwater to streams over time. Ponds like this are often also used to help purify the stormwater, getting more LEED credit for the same dollars. Wetland vegetation absorb contaminants (and promotes wildlife habitation), and even on a small scale, a "rain garden" can help alleviate stormwater runoff problems for residential or small commercial projects. (see Detention vs retention)
Structural Concrete Insulated Panel (SCIP)
SCIP’s and also known as Green Sandwich Panels or Welded Wire Sandwich Panel. SCIP’s are composite panels made of concrete outside panels with a foam insulating core, usually EPS (Expanded Polystyrene). Reinforcing steel wire in the concrete faces connects the sides to each other and improves structural properties.
Usually the recycled material content is up to 60% by volume and waste is 100% recyclable. The foam core is up to 100% recycled, re-ground foam. The wire mesh can be 40% recycled steel and the concrete skins can be up to 40% coal fly ash. SCIP’s can have R-40 insulation performance, resulting in significant energy and cost savings, including downsizing HVAC equipment.
Because the concrete typically is applied through a dry-mix shotcrete process, water usage is greatly reduced when compared to stucco or tilt-up construction.
Portability equals sustainability.
SCIP’s can be used for walls, floors and roofs, in residential, commercial, industrial and institutional applications. SCIP’s also are an excellent sound insulator and can provide fire ratings from 90 minutes to 4 hours.
SCIP’s usually have perforated cores that can serve as chases for electrical conductors and pipes.
Structural Insulated Panel (SIP)
A strong, energy efficient building component used for walls or roofing in homes and commercial buildings. It consists of a core of rigid-foam insulation laminated between two sheets of Oriented Strand Board (OSB). SIP's are fabricated in a plant remote from the building site from detailed design drawings. Hence there is no construction site waste usually associated with conventional frame construction. Also, assembly of the SIP's is much faster than conventional framing. SIP's can be placed at any angle, since each panel is structurally intact and self supporting. Usually no additional insulation is required, due to the foam core material.
Switchable glazing (see Solar Heat Gain Coefficient)
Thermal bridge
Usually this is an undesirable situation where a highly conductive element (such as a metal channel or beam in the building envelope) bypasses a less conductive element (such as insulation) and allows heat transfer through conduction through the building walls. In essence - a thermal short circuit through the insulation system. (see Heat transfer)
Thermal buffer
A building space or structural element that isolates one space from another to maintain different temperatures. This serves to reduce the heating and cooling load. For instance, a sealed attic or crawlspace can serve as a thermal buffer between the outside and inside of a building.
Thermal by-pass
An undesired opening between a conditioned and unconditioned space (like inside and outside a building) that allows actual air movement (meaning convection - see Heat transfer), compromising the air tightness of the building envelope.
Thermal flywheel
A solid, liquid, or gaseous mass that absorbs and stores heat during one time period and releases it at another time in a repetitive pattern. Usually the time period is a day, and the heat is from the sun. But it could be an industrial plant releasing process heat. A solid masonry wall or a double layer of drywall are simple examples, but some complex examples involve large tanks of water or even ice.
Tight Construction
Building in a manner that reduces or eliminates gaps and holes in a building's exterior envelope. This reduces waste and makes a building more energy efficient. It is accomplished through best design practices, including proper air sealing and ventilation, and outstanding workmanship during construction.
Toilet, dual flush
Design strategy intended to reduce wasted water. This fixture has two separate actuation switches/buttons. One switch flows a small volume of water and the 2nd switch flows a higher volume of water. These units usually cost more initially, but save in operating expense - typically resulting in a payback period on the order of 2-3 years.
Toilet, low flow
Design strategy intended to reduce wasted water. Through careful design, this toilet uses less water per flush than a traditional toilet. These units usually cost more initially, but save in operating expense - typically resulting in a payback period on the order of 2-3 years.
Ton
Measure of refrigeration power, equal to 12,000 Btu/hr. (see Energy or Power)
Urban heat islands
Dark-colored surfaces absorb heat from the sun more than light-colored surfaces. In urban areas, a combination of dark surfaces and a lack of shade intensify this effect. One solution is the use of lighter-colored materials in building construction. The use of well-placed vegetation to increase shade or green roof systems can also minimize these effects and increase energy efficiency.
This is a year-round phenomenon whereby dark-colored surfaces (like roofs and asphalt pavement) absorb the sun’s heat more than light-colored surfaces (like concrete, reflective roofing, or vegetation), resulting in widespread elevated air temperatures in urban areas. It is more of a problem in the summer, when the downtown temperatures in St. Louis can climb above 100 degrees while the suburbs are in the 80’s or low 90’s. Because of the “Thermal Flywheel” effect, the elevated temperatures can remain through the night and continue into the next day.
This increases the need and demand on HVAC systems, greatly increasing energy usage, causing health threats to residents without air conditioning, damaging vegetation, and a host of other problems.
One solution is the use of lighter-colored materials in building construction, and provide open space for vegetation and shade. Building roofs are a big contributor to the urban heat island effect - green roof systems or EnergyStar ® compliant roofing can minimize this impact and increase building energy efficiency.
Urinal, waterless
A bathroom fixture that does not use water to capture and convey liquid waste. A chemical seal maintains sanitary conditions and contains odor. A very effective means of reducing water use, but requires greater care during maintenance, and may be problematic with local installers.
U-value
Measure of the radiant heat transmittance of a window. (see Heat transfer) Lower is better, with target less than or equal to 0.40 for windows. See www.energystar.gov for more information.
Vapor barrier
A continuous barrier in a building exterior wall. The vapor barrier is intended to keep water vapor from migrating into the walls from the "warm side", cooling to the "dew point", and condensing inside the wall to form liquid water that can support mold growth and degradation of the wall materials. This is a great idea, but the problem in St. Louis is that there is no "warm side" that is the same all year. In the summer, the warm side is outside, and in the winter it is inside the building. A vapor barrier cannot be used on both sides, because that would trap moisture inside the wall. So many local architects recommend not using a vapor barrier at all in St. Louis. Instead it is important to design and build walls that can dry either to the outside or inside of the building and won't trap moisture inside the walls.
Variable frequency drive (VFD)
A conventional AC motor can only turn at a specific speed, called "synchronous speed", which is based on the set frequency of the AC power supply and how the windings of the motor are configured. Utility-provided AC current is a 60Hz source, resulting in the familiar sound of most AC motors in this country from ventilation fans to pumps: either 1200Hz, 1800Hz, or 3600Hz.
But efficiency of electric motors, particularly in HVAC systems, is dramatically improved by varying the speed of the motor. If improving the efficiency is worth the additional cost (mainly large equipment), a VFD can be used to change the frequency of the electrical current as needed to change the rotation speed of the motor. A VFD employs a solid-state inverter and a sophisticated computer with built-in logic (typically called a Programmable Logic Controller, or PLC) that controls the frequency, and hence the motor speed, based on continuous signaling and feedback from the motor and other system monitoring circuitry.
VFD's are very common in commercial and industrial applications ranging from HVAC to machining and manufacturing, and also in some high-efficiency residential HVAC equipment.
Volatile organic compounds (VOC's)
Volatile = readily migrates from a solid into a gaseous state at room temperature (also called "off-gassing").
Organic = contains carbon molecules in an "organic" ring configuration.
Compound = several/many chemicals or elements combined into one substance (like solvents, paint emulsifier, synthetic fabrics, caulks, adhesives, etc).
Signs or symptoms of VOC exposure may include eye and upper respiratory irritation, nasal congestion, headache and dizziness.
There are many material options of all divisions in green buildings that have very low or no VOC’s – minimizing the risk of VOC exposure. Even if you aren’t planning to certify your office or home as a green building, it is a good idea to use low-VOC materials.
Waste-to-energy
Instead of sending all waste to a landfill, some materials can be incinerated or decomposed to generate steam, heat, or electricity.
Wind power systems, wind turbine
Wind turbines convert wind energy to electricity for powering building systems, plug loads, etc. The turbine, like a PV system, meets some of the demand on the utility service. Wind power is more cost effective than PV, but there can be problems with permitting, placement on the site, and noise. A typical wind turbine tower is 35' high or higher to capture more consistent wind currents. The St. Louis area is not a very consistent locale for wind power, but it still can be a viable renewable supplement to other power sources. Excess power can be stored in a battery storage system or sold back to the utility provider. (see Net metering)
Window, low-E
“Low-E” means low emissivity. This characteristic is imparted by a coating on the glass, and is a measure of the heat reflectance of windows. Low-e windows reflect heat, but not light, keeping the inside of the building warmer in winter and cooler in summer. (see R-value and U-value).
Wood fiber cellulose insulation (see Cellulose insulation)
Xeriscape
Creative landscaping for water and energy efficiency and lower maintenance. The seven xeriscape principles are: good planning and design; practical lawn areas; efficient irrigation; soil improvement; use of mulches; low water demand plants; good maintenance.
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