Glossary of Building Terms

Advanced Framing Advanced Sealing Air Barrier
Autoclaved Aerated Concrete Blower Door Test Building Envelope
Conditioned Space Daylighting Demonstration Home
Embodied Energy Energy Star Engineered Lumber
Fiber-cement Siding Fly ash Forest Stewardship Council Certified Wood Products
French Drain Frost Protected Shallow Foundations Geothermal Heat Pumps (GHP)
Grid-Tie Photovoltaic System Housewrap Hydronic Heating
Infill Innovation Insulating Sheathing
Low Volatile Organic Compounds (VOC) Paints and Stains Low-E Marketable-Home
Multi-Family National Association of Home Builders (NAHB) Research Center Net Metering
Optimum Value Engineering Oriented Strand Board (OSB) Photovoltaic (PV) Modules
R-Value Radon Radon Mitigation
Raised Heel Roof Truss or Energy Heel Sealed-combustion Appliances Single-Family
Slab-on-grade Foundation Solar Tube Transom windows
U-value Vapor Barrier VOC
Xeriscaping Zero Energy House

Advanced Framing

Refers to framing techniques that reduce the amount of lumber used to build a home while maintaining the structural integrity of the building. Using these techniques results in lower material and labor costs and improved energy performance for the building. Because these techniques are not universally known by builders, more planning and training may be needed when using them.

Advanced Sealing

In addition to basic sealing, advanced sealing adds protection to top and bottom plates of walls, at corners, in attics, and between cavities at penetrations for plumbing, electrical, and ventilation.

Back to Top

Air Barrier

A system of materials that enclose a volume of air with minimal air leakage between the enclosed air and the exterior. The effectiveness or adequacy of the air barrier can be measured by the volume of air (in cubic feet per minute) that must be added or removed from the enclosure to maintain a certain pressure difference across the pressure boundary.

Autoclaved Aerated Concrete

(AAC) - A precast, manufactured building stone made of all natural raw materials. It is an economical, environmentally friendly, cellular, lightweight but structurally sound material that features thermal and acoustic insulation, as well as fire and termite resistance. AAC is available in a variety of forms, ranging from wall and roof panels to blocks and lintels.

Back to Top

Blower Door Test

Blower doors are designed to measure how airtight (or leaky) a home is, normally using the parameter of air changes per hour (ach). These tests can be used to determine construction quality and compliance with design or program standards (such as utility home efficiency programs) and to diagnose comfort, indoor air quality, and durability problems.

Building Envelope

The building envelope includes everything that separates the interior of a building from the outdoor environment, including the windows, walls, foundation, basement slab, ceiling, roof, and insulation. It controls the transfer of energy (heat) between the inside and the outside.

Back to Top

Conditioned Space

The interior area supplied with conditioned air from a HVAC system.


The efficient use of natural light in ways that minimize the need for artificial light in buildings. It is achieved by control strategies and adapted components which fall mainly into three categories: 1. conduction components - spaces used to guide or distribute light towards the interior of a building, 2. pass-through components (e.g. windows, solar tubes) - these allow light to pass from one room or section of a building to another, and 3. control elements - specially designed to control the way in which light enters through a pass-through component.

Back to Top

Demonstration Home

Constructed for the purpose of research, demonstration, and education, these homes provide hard data proving that resource efficiency is a viable alternative.

Embodied Energy

All of the energy invested in bringing a material to its final product, including transportation.

Back to Top

Energy Star

A government-backed program helping businesses and individuals protect the environment through superior energy efficiency. Go to http://www.energystar.gov for more information.

Engineered Lumber

Recycled or reconstituted wood materials, which employ laminated wood chips or strands and finger-jointing (gluing large pieces together).

Back to Top

Fiber-cement Siding

Siding composed of cement, sand, and cellulose fiber that has been autoclaved (cured with pressurized steam) to increase its strength and dimensional stability. The fiber is added to reinforce the concrete and to prevent its cracking. Planks come in 5.25" to 12" widths and are about 5/16 inches thick. Fiber-cement siding is termite-resistant, non-combustible, and may be warranted for up to 50 years.

Fly ash

A by-product of coal burning, fly ash is a fine, glass-like powder recovered from gases created by coal-fired electric power generation. Fly ash is an inexpensive replacement for Portland cement used in concrete, while it actually improves strength, segregation, and ease of pumping of the concrete. Fly ash is also used as an ingredient in brick, block, paving, and structural fills. Using coal fly ash conserves energy by reducing the demand for typical pavement materials such as lime, cement and crushed stone, which take energy to produce. Coal fly ash can also replace clay, sand, limestone and gravel, and save the energy costs of mining such materials. Each ton of fly ash used to replace a ton of cement, for example, saves the equivalent of nearly one barrel of oil.

Back to Top

Forest Stewardship Council Certified Wood Products

The Forest Stewardship Council (FSC) has developed an internationally recognized third party certification system for harvesting wood from sustainable sources. Such products are becoming more available from building suppliers. Go to http://www.fscus.org/ for more information.

French Drain

The basic French drain is a drainage system that consists of a trench dug into the ground through and out of an area with poor drainage. The trench is filled with a porous material, usually gravel, crushed stone or slag, along with a perforated polyvinyl chloride (PVC) plastic pipe to collect and channel unwanted ground water. It is better to install the drain during construction, rather than later, to avoid problems digging around utilities, porches, and other obstacles. French drains will clog over time, so they need to be cleaned periodically.

Back to Top

Frost Protected Shallow Foundations

(FPSF) protect foundations against frost damage without the need for excavating below the frost line. A FSPF has insulation placed strategically around the outside of a foundation to direct heat loss from the building toward the foundation, and also to use the earth's natural geothermal energy.

Geothermal Heat Pumps (GHP)

These ground-source heat pumps use the natural heat storage capacity of the earth or ground water to provide energy efficient heating and cooling. GHPs should not be confused with air-source heat pumps that rely on heated air. They use the relatively constant temperature of the ground or water several feet below the earth's surface as a source of heating and cooling. GHPs can also provide domestic hot water. They can be used for virtually any size home or lot in any region of the U.S.

Back to Top

Grid-Tie Photovoltaic System

A home-based solar electric generation system that is tied into the utility grid. Photovoltaic (PV) modules or panels are used as collectors. Instead of costly batteries, the grid is used to "store" excess solar power. The excess is then either sold back to the highest bidder or in most states, net metering laws require utilities to credit the homeowner (run the meter backwards) whenever the system produces more power than the home consumes.


Any of several spun-fiber polyolefin rolled sheet goods for wrapping the exterior of the building envelope. Marketed as an air barrier that can "breathe" with respect to water in the vapor phase but repel liquid water, its properties do not include uni-directional vapor permeability. Builders should understand their region before determining how to use a housewrap and other barriers, if any, before building.

Back to Top

Hydronic Heating

Also known as radiant heating. A hot water heating system where hot liquid is pumped through piping, (often PEX flexible piping) and the warmth is evenly radiated over an extended period of time. Typically, hydronic heating is laid within a thermal mass floor or wall, but can also be installed within a ceiling. The thermal mass helps to absorb the heat and extend the period of release. Hydronic heating systems are generally very efficient and provide a more comfortable and consistent warmth than blown-air or electric baseboard heat.


The use of vacant land and property within a built-up area for further construction or development, especially as part of a neighborhood preservation or limited growth program.

Back to Top


Each home highlights at least one "innovation". An innovation can be a technique, partnership, or application used to provide a creative solution to a problem posed by the site and / or goals of the project. It can not be an off-the-shelf product unless used in a unique way. HAA strives to draw connections to the climatic, cultural and/or financial aspects of using an innovative approach.

Insulating Sheathing

These are non-structural insulating board products that are most often cited for their varying R-values, or insulative qualities. Insulative sheathing has other important qualities related to how well a house performs such as: vapor permeability, bonding qualities, and how well they act as a drainage plane.

Back to Top

Low Volatile Organic Compounds (VOC) Paints and Stains

Harmful VOCs evaporate (volatilize) easily at room temperature and often have a sharp smell. They are contained in many products, such as office equipment, adhesives, carpeting, upholstery, manufactured wood products, paints, solvents, pesticides, and cleaning products. Many low-VOC versions of products reduce risks to human health and the environment, and are the preferred alternative to people concerned with indoor air quality.


Most often used in reference to a coating for high-performance windows, the "e" stands for emissivity or re-radiated heat flow. The thin metallic oxide coating increases the U-value of the window by reducing heat flow from a warm(er) air space to a cold(er) glazing surface. The best location for the coating is based on whether the primary heat flow you want to control is from the inside out (heating climates) or the outside in (cooling climates).

Back to Top


Built or retrofitted for the open market, these homes utilize innovative ideas and technology to minimize waste, prevent pollution and increase efficient use of resources.


Houses built for multiple families such as duplexes, apartments or condominiums.

Back to Top

National Association of Home Builders (NAHB) Research Center

The NAHB Research Center is a wholly-owned subsidiary of the National Association of Home Builders. It is a "green building" pioneer, researching many new resource-efficient techniques and technologies, and promoting results to green builders throughout the country. Go to http://www.nahb.org/ for more information.

Net Metering

Net-metering is a simplified method of metering the energy consumed and produced at a home or business that has its own renewable energy generator or collector, such as a wind turbine or photovoltaic panels. Under net metering, excess electricity produced by the renewable energy system will spin the existing home or business electricity meter backwards, effectively banking the electricity until it is needed by the customer. This provides the customer with full retail value for all the electricity produced.

Back to Top

Optimum Value Engineering

See Advanced Framing

Oriented Strand Board (OSB)

OSB is manufactured from waterproof heat-cured adhesives and rectangularly shaped wood strands that are arranged in cross-oriented layers, similar to plywood. This results in a structural engineered wood panel that shares many of the strength and performance characteristics of plywood.

Back to Top

Photovoltaic (PV) Modules

Panels that collect the sun's energy. There are two main types: crystalline and amorphous (also called thin-film). Crystalline modules are either mono or poly. Both mono and polycrystalline modules are covered with tempered glass in an aluminum frame. Amorphous modules are newer to the market. The thin film can be bonded directly on to a metal roof, adding durability. Amorphous PV requires more space per generated watt than crystalline PV. But, amorphous PV are not as readily affected by high temperatures and partial shading.


A measure of a material's resistance to heat flow (thermal resistance). The higher the R-value of a material, the greater the insulating capability. The R-value of a material is the inverse of the U-Value for that material (See U-value).

* R-value Insulating Material
0.6 per ½ inch plywood
0.8 per 4 inch brick
2.5 per inch vermiculite
3.7 per inch fiberglass and cellulose
> 4 per inch foam
* R-value is in units of Fahrenheit degrees x hours x square feet per Btu
Source: Energy Information Administration http://www.eia.doe.gov/

Back to Top


Radon is a cancer-causing, radioactive gas. Radon comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air we breathe. Radon can be found all over the U.S. It can reach toxic levels in any type of building that does not have adequate ventilation. The Surgeon General says radon is the second leading cause of lung cancer in the United States. A level considered safe within an enclosed space is 4 picoCurie per liter (pCi/L).

Radon Mitigation

Radon-resistant construction techniques can be effective in preventing radon entry. When installed properly and completely, these simple and inexpensive techniques can help reduce indoor radon levels in homes. In addition, installing both passive venting systems and hookups for active (motorized) venting at the time of construction makes it easier and less expensive to reduce radon levels further if the passive techniques don't reduce radon levels to below 4 picoCurie per liter (pCi/L), the level considered safe. Every new home should be tested after occupancy, even if it was built radon-resistant.

Back to Top

Raised Heel Roof Truss or Energy Heel

A raised heel truss adds an extension to the top of the exterior wall of the home. This space allows for a full depth of insulation to be applied where the side walls and the roof of the home intersect, making the roof framing more energy-efficient

Sealed-combustion Appliances

Appliances with the ignition heating element sealed and vented to the outdoors to prevent gases from mixing with and polluting indoor air.

Back to Top


Houses built for only one family.

Slab-on-grade Foundation

These floors are often the least expensive foundation system and can expedite the construction process. The foundation consists of a concrete slab poured over at least 4 inches of gravel and a layer of 10-mil polyethylene. Virtually any floor covering works well with a slab, although wood flooring systems may require installation of wooden furring strips prior to attaching the wood flooring material. There are benefits and drawbacks to a slab-on-grade foundation the homeowner is encouraged to understand before using this technique.

Back to Top

Solar Tube

A solar tube is a columnar skylight with a silverized tube that usually goes through the attic and provides natural daylight into a room. It is most effective in a room that does not have direct sunlight, such as a north facing room, or where putting in a window would be impractical, such as a bathroom.

Transom windows

A window that fits over the top of a door or the upper part of an interior wall, primarily for additional light, natural ventilation, and aesthetic value.

Back to Top


The measurement of conductive heat transfer through a given building material, such as glass, wood, or insulation. U-values are typically used in the window industry. The lower the U-value, the greater a window's resistance to heat flow and the better its insulating value. The U-value of a material is the inverse of the R-value of that material (R-value=1/U-value).

Vapor Barrier

A material that severely restricts the movement of water vapor from one side of the material to the other. Properly choosing where and how to use vapor and air barriers is complicated, and based on the interaction of climate factors.

Back to Top


Volatile organic compound - Highly evaporative, carbon-based chemical substances that produce noxious, often toxic, fumes. They are found in many paints, caulks, stains, adhesives, carpet, and manufactured products used in cabinets and furniture.


Climate-tuned landscaping that minimizes outdoor water use while maintaining soil integrity and building aesthetics. Typically includes emphasis on native plantings, mulching, and no irrigation or limited drip/subsurface irrigation.

Back to Top

Zero Energy House

This is any house that averages out to net zero energy consumption. A zero energy home can supply more energy than it needs during peak demand, typically using one or more solar energy strategies, energy storage and/or net metering. In a zero energy home, a tight building envelope and efficient HVAC systems, appliances and lighting all significantly contribute to less demand for energy.

This showcase is for educational and informational purposes. It is meant to provide ideas and contacts for further assistance. We do not endorse particular products or services. It is the responsibility of the user to check references and facts prior to making use of the information.

The contents of this website are public information and may not be copyrighted in any form, sold or used for profit in any way. The information within the showcase may only be printed when this notice is included and credit is given to the Peaks to Prairies Pollution Prevention Information Center and the individuals cited in each home profile.