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PDFAppraiser's Glossary of Green Building Terms A - M
2030 Carbon Neutral Challenge
This is a green-building challenge originated by New Mexico architect Ed Maisra, a leader in the green-building field, and taken up as a cause by the American Institute of Architects. The goal of the challenge is for buildings to be “carbon neutral,” meaning they do not add any extra climate-changing carbon to the atmosphere by the year 2030. (See more)
Air Changes Per Hour (ACH)
The movement of a volume of air in a given period of time; if a house has one air change per hour, it means that the air in the house will be replaced in a one-hour period. (Source: City of Seattle Green Building Glossary)
Air and Heat Exchangers
In the ideal healthy house, fresh air is brought in in a controlled manner. In the past, houses were made with a lot of leaks, so there was natural exchange of fresh air. After the energy crisis of the 1970s, building codes changed to required homes to be built tighter. But this created new problems when old, stale air stayed too long. Think about smelling the breakfast bacon in the afternoon. That is a house where the air is not being exchanged. In order to bring in fresh air and exhaust out without wasting energy, heat exchangers place the outgoing conditioned air next to the incoming non-conditioned air and allow the heat to transfer between the two.
Air Leakage – optional factor in window rating labels
Air Leakage (AL) is indicated by an air leakage rating expressed as the equivalent cubic feet of air passing through a square foot of window area (cfm/sq ft). Heat loss and gain occur by infiltration through cracks in the window assembly. The lower the AL, the less air will pass through cracks in the window assembly. (Source: National Fenestration Rating Council)
ASHRAE
American Society of Heating, Refrigeration and Air Conditioning Engineers (See more)
Awnings
In harsh climates with much summer heat, strategically placed awnings can cut the sun coming into the house, and save energy. The ideal situation is for the awnings to block the summer sun when it sits high in the sky, but not block the winter sun, which sits lower in the sky.
Blower Tests
Much energy is lost through air leaks in a house. It could be cooled air or heated air that is leaking out. It might leak through windows, through outlets in walls, into the attic, etc. To determine how much air is leaking out, blower tests are done to measure that. Many green building rating programs, such as LEED, require blower tests in order to get certification. So if a house is certified under LEED, you know that it passed a blower test.
Building Related Illness
Diagnosable illness whose cause and symptoms can be directly attributed to a specific pollutant source within a building (e.g., Legionnaire's disease, hypersensitivity, pneumonitis). (Source: City of Seattle Green Building Glossary)
Carbon Dioxide Monitoring
A method for determining indoor air quality by using the concentration of carbon dioxide as an indicator. Although the level of CO2 is a good general indicator of air quality, it is reliant on the presence of certain conditions and must be applied accordingly. (Source: City of Seattle Green Building Glossary)
Carbon Dioxide Sensor
Device for monitoring the amount of carbon dioxide in an air volume.
Carbon Monoxide (CO)
A colorless, odorless, poisonous gas produced by incomplete fossil fuel combustion.
Carpeting
At one time, wall-to-wall carpeting was seen as added value to a home. And it still could be. But as people gain awareness of indoor air quality and as people continue to get sick with asthma, allergies and other illnesses, they could likely begin to see carpeting as a negative rather than a positive. Carpeting is impossible to get completely clean, harbors dust and mites, and if it’s new, can outgas chemicals. New carpeting made with indoor air quality in mind includes Interface (www.interfaceflor.com), which uses nontoxic adhesives. Plus, Interface carpeting is recyclable. In the future, homebuyers may look upon recyclable carpeting as a plus.
Cellulose Insulation
Insulation alternative to glass fiber insulation. Cellulose insulation is most often a mixture of waste paper and fire retardant, and has thermal properties often superior to glass fiber. Glass fiber batt insulation often contains formaldehyde, which can adversely affect indoor air quality and human health, and the glass fibers themselves are hazardous if inhaled and irritating to the skin and eyes. Specify cellulose insulation with high-recycled content for maximum environmental benefit. (Source: City of Seattle Green Building Glossary)
Certified Lumber
General shorthand term for lumber that has been certified sustainable harvest by an independent certification authority such as the Forest Stewardship Council, or FSC.
Chain of Custody
A document that tracks the movement of a wood product from the forest to a vendor and is used to verify compliance with FSC guidelines. A “vendor” is defined as the company that supplies wood products to project contractors or subcontractors for on-site installation. (Source: City of Seattle Green Building Glossary)
Comfort
An increasingly informed public may come to understand the importance of comfort in a home, and what makes it comfortable. Under-insulated walls that allow outside heat or cold to transfer to the inside create uncomfortable living environments. No matter how high the heater is blasting away on a winter day, when the walls inside are icy to the touch, that coldness sucks heat out of the human bodies inside. It’s simply the law of physics that air moves from warm to cold. Likewise, a house is made more comfortable with natural light during the daytime, and with lights strategically placed for their proper function. A green house is a smart house that relies on design rather than massive amounts of voltage coming from massive lights. An informed public will eventually understand what makes a house comfortable, and value those houses more than “dumb” houses.
Commissioning
The process of ensuring that systems are designed, installed, functionally tested, and capable of being operated and maintained to perform in conformity with the owner’s project requirements. (Source: City of Seattle Green Building Glossary)
Compact Fluorescent Lamp (CFL)
Small fluorescent lamps used as more efficient alternatives to incandescent lighting. Also called PL, CFL, Twin-Tube, or BIAX lamps.
Composite Wood
A product consisting or wood or plant particles or fibers bonded together by a synthetic resin or binder (i.e., plywood, particle-board, OSB, MDF, composite door cores).
Condensation Resistance — optional factor in window rating labels
Condensation Resistance (CR) measures the ability of a product to resist the formation of condensation on the interior surface of that product. The higher the CR rating, the better that product is at resisting condensation formation. While this rating cannot predict condensation, it can provide a credible method of comparing the potential of various products for condensation formation. CR is expressed as a number between 0 and 100. (Source: National Fenestration Rating Council)
Conditioned Space
The part of a building that is heated or cooled, or both, for the comfort of occupants.
COP
Coefficient of Performance, COP, is the ratio of energy input to heating capacity. This is the instantaneous measurement of the heating performance of your heat pump. It is comparable to knowing how many miles per gallon of gasoline your car gets when it is going full speed. You can find the COP on the nameplate of your heat pump. (Source: Lawrence Berkeley National Laboratory)
Cradle-to-Cradle
A term used in life-cycle analysis to describe a material or product that is recycled into a new product at the end of its defined life.
Cradle-to-Grave
A term used in life-cycle analysis to describe the entire life of a material or product up to the point of disposal. Also refers to a system that handles a product from creation through disposal. (Source: City of Seattle Green Building Glossary)
Daylighting
This topic spans the categories of both energy efficiency and comfort. It only makes sense that energy will be saved if lights do not have to be used during daylights. Yet unless a house is designed with that goal in mind, or retrofitted later to accomplish that goal, a house will likely need to have artificial lights burning all day long when certain areas are occupied. Increasingly, new-home builders are including operable skylights and solar tubes in those areas where windows are not feasible. As consumers become more educated about green building, they will recognize homes that have ample daylighting, and those that don’t.
Demand Hot Water System
Hot water heaters designed to provide instantaneous hot water, rather than storing preheated hot water in a tank. Such devices can serve an entire home, or be "point-of-use", serving an individual water use. Benefits include elimination of "standby losses", or energy wasted keeping stored water warm, and with point of use devices, reduction or elimination of water wasted waiting for water to get warm, as well as conductive losses as water travels through pipes. Electric demand systems tend to use a large amount of energy; gas-fired units with standing pilot lights lose much of their efficiency due to the ongoing pilot light. (Source: City of Seattle Green Building Glossary)
Depressurization
A condition that occurs when the air pressure inside a structure is lower that the air pressure outdoors. Depressurization can occur when household appliances such as fireplaces or furnaces, that consume or exhaust house air, are not supplied with enough makeup air. Radon may be drawn into a house more rapidly under depressurized conditions. Back drafting of furnaces and vented appliances can also occur with depressurization, introducing exhaust gases into the house. (Source: City of Seattle Green Building Glossary)
Dual-glazed
Same as dual-paned windows.
Ducting in conditioned space or not
When the ducts carrying heated or cooled air run through unconditioned space — an uninsulated attic, for instance — much of that heat and coolness will be drawn out of the thin walls of the ducting. And if the ducts are leaking, such as when the tape or caulking is cracked, even more of that heat or cold is lost. And that is money lost. Ideally, the ducts should be inside conditioned space, which means inside what is known as the “envelope” of the house where insulation separates the inside and outside air. Additionally, the ducts should be sealed well and not leaking.
Durability
The keystone for all green building is durability. If a material or system is not durable, made with quality products and construction, it is not green. No matter what kind of certified forest the framing wood came from, if that wood is not protected from excess moisture with proper flashings and house wrap and siding, for instance, that wood is truly not green. The old way of building homes was short-sighted in order to put the maximum number of owners into houses quickly, a habit that began on a big scale in Levittown, N.Y., when the Levitt brothers learned how to build houses using an assembly line method of moving workers from house to house to house in quick succession. At the time, these quickly built homes served their purpose to created housing for soldiers returning from WWII.
Today, however, as the world become ever more populated, it’s becoming clearer that building homes with cheap materials that will need replacing in a few years – like exterior trim made from inferior pine – is not sustainable. And this is where tradeoffs need to be made when evaluating green building priorities. Vinyl fencing, for instance, will last a lot longer than wooden fencing. However, the process to produce vinyl is so onerous to conservationists that many feel it has no place at all in green building. As people become more aware of durability as a money- and labor-saving benefit to them, durable features in homes will add noticeable value.
Energy Efficient Mortgages
The purpose of EEMs is to allow the cost of utilities to factor into the calculations for how much house people can afford. For instance, if utilities for a house cost $200 a month, and utilities for an energy-efficient house are $50, theoretically then homeowners should be able to qualify for a loan that costs $150 a month more. According to some bankers, these loans have not been terribly popular. People don’t really want a bigger mortgage, and it’s easier to ignore the cost of utilities. These mortgages have helped some low-income people get into a house when the budget is really tight.
Energy or Water Conservation
Using less energy or water. Conservation can imply a lifestyle change or a reduced level of service. Lowering thermostat settings or installing a shower flow restrictor are examples of energy conservation. (Source: City of Seattle Green Building Glossary)
Energy or Water Efficiency
Using less water or energy to perform the same tasks. A device is energy-efficient if it provides comparable or better quality of service while using less energy than a conventional technology. Building weatherization or high-efficiency showerheads are efficiency technologies. (Source: City of Seattle Green Building Glossary)
Energy Star
Program administered by the Environmental Protection Agency that evaluates products based on energy efficiency. Energy Star Rating is the rating a building earns to compare building energy performance to similar buildings in similar climates. (See more)
Energy Star-qualified Appliances
The Energy Star rating system was started by the U.S. Dept. of Energy, and began in 1990 with personal computers and printers. Over subsequent years, other categories of appliances were added: refrigerators, air conditioners, etc. An Energy-star rated appliance can save hundreds of dollars over a year’s time. The latest category to potentially get an Energy Star rating is water heaters, including gas tank heaters and gas tankless heaters. As the cost of energy rises, Energy Star-rated appliances are likely to become more desired.
Engineered Lumber/Wood
Composite wood products made from lumber, fiber or veneer, and glue. Engineered wood products can be environmentally preferable to dimensional lumber, as they allow the use of waste wood and small diameter trees to produce structural building materials. Engineered wood products distribute the natural imperfections in wood fiber over the product, making them stronger than dimensional lumber. This allows for less material to be used in each piece, another environmental benefit. Potential environmental drawbacks with engineered wood include impacts on indoor environmental quality due to offgassing of chemicals present in binders and glues, and air and water pollution related to production. (Source: City of Seattle Green Building Glossary)
Fans
Ceiling fans that move air around can sometimes eliminate the need for air conditioning. Homes with abundant fans will likely use less air-conditioning energy.
Formaldehyde
A colorless, pungent, and irritating gas, CH20, used chiefly as a disinfectant and preservative and in synthesizing other compounds like resins. This chemical is known to be toxic to humans, and yet it’s everywhere in homes: glues, carpet backing, plywood, cabinets, etc. Green homes have a minimum of formaldehyde in them. This goes under the category of health and comfort. With the increase in asthma and breathing problems, homebuyers are likely to value homes without formaldehyde.
Framing
Typical framing for homes is 2-by-4 studs 16 inches apart. Green homes are made with 2-by-6 studs 24 inches apart. With this configuration, less lumber is used, and the walls are thicker, which allows for more insulation. This is also called value-engineered framing and is used in green homes. The savings in building costs will not affect the value of a home, but the thicker walls will become more desirable as consumers become more aware of green homes.
Forest Stewardship Council (FSC)
A third-party certification organization, evaluating the sustainability of forest products. FSC-certified wood products have met specific criteria in areas such as forest management, labor conditions, and fair trade. (See more)
Geothermal/Ground Source Heat Pump
These heat pumps are underground coils to transfer heat from the ground to the inside of a building. This type of heat pump can realize substantial energy savings over conventional heat pumps, by using the naturally more stable temperature of the earth as its heat source. (Source: City of Seattle Green Building Glossary)
Green Globes
Green Globes is an environmental assessment, education and rating system that is promoted in the United States by the Green Building Initiative, a Portland, Oregon-based non-profit. (See more)
Green Seal
Founded in 1989, Green Seal provides science-based environmental certification standards for products such as paints, adhesives and paper products. Such a standard helps answer the question: How do you know if it’s green? People who remodel homes with interior non-toxic paint certified by Green Seal can rightly claim that their home is greener than one painted with a fume-emitting paint. This could be especially notable for homebuyers who have allergy problems, or asthma or other breathing issues. (See more)
Graywater (also spelled greywater and gray water)
Defined by the Uniform Plumbing Code (UPC) in its Appendix G, titled “Gray water Systems for Single-Family Dwellings,” as “untreated household wastewater which has not come into contact with toilet waste. Grey water includes water from bathtubs, showers, bathroom washbasins, and water from clothes-washer and laundry tubs. It shall not include wastewater from kitchen sinks or dishwashers.” The International Plumbing Code (IPC) defines graywater in its Appendix C, titled “Graywater Recycling Systems,” as “wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks.” Some states and local authorities allow kitchen sink wastewater to be included in graywater. Other differences with the UPC and IPC definitions can probably be found in state and local codes. (Source: City of Seattle Green Building Glossary)
Gray Water Reuse
A strategy for reducing wastewater outputs from a building, by diverting the gray water into productive uses such as subsurface irrigation, or on-site treatment and use for non-potable functions such as toilet flushing. Gray water reuse is restricted in many jurisdictions. (Source: City of Seattle Green Building Glossary)
Green Design
A design, usually architectural, conforming to environmentally sound principles of building, material and energy use. A green building, for example, might make use of solar panels, skylights and recycled building materials. (Source: City of Seattle Green Building Glossary)
Green Label
A certification program by the Carpet and Rug Institute for carpet and adhesives meeting specified criteria for release of volatile compounds.
Greenwash
Disinformation disseminated by an organization so as to present an environmentally responsible public image. (See the Sins of Greenwashing)
Heat Exchanger
Device for exchanging heat present in wastewater or stale air to preheat incoming water or air.
Heat Pump
A heat pump is basically an air conditioner with a reversible valve that allows it to operate in reverse, removing heat from a house and shunting it outdoors in the summer, and removing heat from outdoor air and shunting it into a house in the winter. Because heat pumps do not actually create heat—they just move it from one place to another—heat pumps are more efficient than other forms of heating. (Source: Lawrence Berkeley National Laboratory)
Heat Recovery Unit/Ventilator
An air-to-air heat exchanger with balanced exhaust and supply fans that meet all necessary ventilation needs without producing drafts or air pressure imbalance on a heating or cooling system. (Definition: Washington State University Cooperative Extension Energy Program)
HERS Rating
Home energy rating is an analysis of a home's projected energy efficiency in comparison to a 'reference home' based on the 2006 International Energy Conservation Code. A home energy rating involves both an analysis of a home’s construction plans, as well as onsite inspections and testing by a certified Home Energy Rater.
A Home Energy Rater uses specially designed software to analyze the expected energy use of the home based on the home’s construction plans. This analysis yields a projected, pre-construction rating score for this home (called a HERS Index). When the rating is being conducted for the purposes of qualifying the home to the earn the ENERGY STAR, the rater then works with the builder to identify the energy efficiency improvements needed to ensure the house will meet ENERGY STAR performance guidelines. The rater then conducts onsite inspections, typically including a blower door test (to test the leakiness of the house) and a duct test (to test the leakiness of the ducts). Results of these tests, along with data from the software analysis, are used to generate a final HERS Index score for the home.
The lower a home’s HERS Index, the more energy efficient it is. A home built to code scores a HERS Index of 100, while a net zero energy home scores a HERS Index of 0. Each 1-point decrease in the HERS Index corresponds to a 1% reduction in energy consumption compared to the HERS Reference Home. Thus a home with a HERS Index of 85 is 15% more energy efficient than the reference home and a home with a HERS Index of 80 is 20% more energy efficient. (Source: Energy Star)
High Efficiency
General term for technologies and processes that require less energy, water, or other inputs to operate. A goal in sustainable building is to achieve high efficiency in resource use when compared to conventional practice. Setting specific targets in efficiency for systems (e.g., using only EPA Energy Star certified equipment, furnaces with an AFUE rating above 90%, etc.) and designs (e.g., watts per square foot targets for lighting) help put this general goal of efficiency into practice. (Source: City of Seattle Green Building Glossary)
High Performance Glazing
Generic term for glazing materials (window glass) with increased thermal efficiency.
Home Energy Audit
An audit can help assess how much energy a home uses and evaluate what measures to take to improve efficiency. Types of audits explained by Energy Star.
Hydronic Heating
A space heating system that uses water circulated through a radiant floor or baseboard system or a convection or fan coil system.
Indoor Air Quality
A major component of green homes is the quality of the air inside. This is affected by the materials that go into a house, as well as the way the air and moisture are handled. Carpeting is usually seen as a detriment to good indoor air, while hard surface floors like wood and tile are easier to keep free of dust and mites and pet dander. No VOC-paints and no formaldehyde contribute to good indoor air.
Insulated Concrete Form (ICF)
Expanded polystyrene forms that are left in place after the concrete is poured for a foundation or wall. The foam increases the thermal performance of the structure over non-insulated concrete.
Insulation and R-value
Better insulation is necessary for a home to be both energy efficient and comfortable. The R-value of the insulation relates to how much resistance there is to temperature flow. Windows also have R-value. The higher the R-value, the better the insulation. Insulation most often found in green homes includes blown-in Icenyne, as opposed to rolled battsi of insulation.
Lead
Prior to 1978, paints included lead, which has been found to cause brain damage in young children. In 1978, lead in paint was outlawed, but there is still lead paint on walls and trim all over the country, and is potentially dangerous for the home’s inhabitants. The EPA only recently passed rules requiring contractors to take special care to protect young children and pregnant women from the dust that might contain lead during remodeling. (See EPA’s lead site)
LEED
A green building rating system developed by the U.S. Green Building Council. LEED stands for Leadership in Energy and Environmental Design, and evaluates a building from a systems perspective. By achieving points in different areas of environmental performance, a building achieves a level of "certification" under the system.
Lighting
Until fairly recently, there were few options to save energy and money on lighting. Incandescent bulbs, which use a lot of energy and create a lot of heat, were pretty much the only option. Fluorescent lights, which are more energy-efficient were associated with flickering light and an unattractive color. Recent advancements in technology have made CFLs (compact fluorescent lamps) very affordable. They are very long lasting and use a fraction of the energy of incandescents. However, concerns over mercury in the bulbs have slowed enthusiasm about this technology. However, it seems that incandescents are out, and will eventually be outlawed. The next green lighting preference will likely be LED lights. However, they are currently expensive and the light is not bright enough for some consumers. That will change.
Linoleum
A resilient flooring product developed in the 1800s, manufactured from cork flour, linseed oil, oak dust, and jute. Linoleum’s durability, renewable inputs, anti-static properties, and easy-to-clean surface often make it classified as a "green" building material. (Source: City of Seattle Green Building Glossary)
Local/Regional Materials
Building products manufactured and/or extracted within a defined radius of the building site. For example, the US Green Building Council defines local materials as those that are manufactured, processed and/or extracted within a 500-mile radius of the site. Use of regional materials is considered a sustainable building strategy due to the fact that these materials require less transport, reducing transportation-related environmental impacts. Additionally, regional materials support local economies, supporting the community goal of sustainable building. (Source: City of Seattle Green Building Glossary)
Low Emissivity (low-E) Windows
Window technology that lowers the amount of energy loss through windows by inhibiting the transmission of radiant heat while still allowing sufficient light to pass through.
MDF (Medium Density Fiberboard)
A composite wood fiberboard, used for cabinetry and other interior applications. MDF containing urea formaldehyde can contribute to poor indoor air quality. (Source: City of Seattle Green Building Glossary)