Glossary of Common Terms

Learn some of the basics of home performance. 

Air Sealing:  The practice of installing appropriate materials, such as caulk or foam, to stop airflow in certain areas of a home.

Blower Door Test: A test used to measure a home's airtightness and locate air leakage paths. A blower door is a powerful fan that mounts into the frame of an exterior door. The fan moves air in or out of the house, changing the air pressure inside to exaggerate air leaks through unsealed cracks and openings. Technicians use these tests to determine the air infiltration rate of a building, identify locations to be sealed, and measure results of air sealing work.

Building Envelope: The assembly of elements comprising the exterior enclosure of a building, including walls, roof, foundation, windows, and doors.

Combustion Safety Test: Combustion safety is the general term for evaluating fuel-burning equipment in the home. In general, these procedures include checks for fuel leaks, carbon monoxide, and to ensure that waste gases exit the home through the chimney or venting system.

Diagnostic Tests: Procedures used to measure and assess the performance of components of the home using specialized testing equipment, including blower door testing and combustion safety testing. Diagnostic tests are often conducted before and after the installation of home upgrades to measure the net improvement and to ensure that safety standards have been met.

Ductwork: A network of metal, fiberboard, or flexible tubes throughout a space which delivers air from an HVAC unit to the respective zones of a home or office.

Energy Audit: An “energy assessment” or “energy study” to determine where, when, why, and how energy is used in a home, and to identify opportunities to improve efficiency. It includes an evaluation of a home based on data from inspections, diagnostics, data collection, analyses, and reporting, which identifies opportunities for the homeowner to improve energy efficiency. See also "home performance assessment.”

Energy Efficiency: The concept of using less energy to provide the same service.

Greenhouse Gas: A gas that traps the sun’s heat in the atmosphere. When these gases are trapped in the atmosphere (and not reflected back into space), the planet becomes warmer than it would be otherwise. This process is commonly referred to as the greenhouse effect. Greenhouse gases include water vapor, carbon dioxide, methane, ozone, chlorofluorocarbons, and nitrogen oxides; gases which are produced and sometimes released to the atmosphere when generating energy to power our homes.

Home Energy Assessment: An evaluation of a home based on data from inspections, diagnostics, data collection, analyses, and reporting, which identifies opportunities for the homeowner to improve energy efficiency. See also "energy audit.”

Home Energy Upgrade: Individual home improvement measures or packages of measures completed to reduce energy consumption in the home.

Home Performance: The systematic approach to improving the comfort, health, safety, energy efficiency, and durability of a home. (BPI Reference Guide, 1st Ed.)

Home Performance Assessment:  An evaluation of a home’s condition and energy performance conducted by an expert in Home Performance with ENERGY STAR.

Home Performance Contractor or Home Performance Professional: A company or individual who installs or supervises the installation of home energy upgrades. This company or person may specialize in energy assessments, home inspections, or improvements related to air or duct sealing, insulation, HVAC, or other related services.

Home Performance Measure: The installation or modification of equipment or other building components, in order to improve a building’s performance and energy efficiency (e.g., insulation, air sealing, duct sealing, appliance replacement).  See also “Energy Efficiency Measure.”

Home Performance with ENERGY STAR Sponsor: Organizations that take on the responsibility of administering home performance programs in local markets. Sponsors are instrumental in developing and supporting markets for home performance services following the Home Performance with ENERGY STAR approach. Sponsors are responsible for fostering the market for home performance services by managing and monitoring the performance of their implementation vendors and participating contractors to ensure that quality standards are met.

HVAC: The equipment, distribution system and terminals that provide, either collectively or individually, the processes of heating, ventilating or air conditioning to a building or portion of a building.

Indoor Air Quality: Attributes of the air inside a building (indoor climate), including gaseous composition, humidity, temperature and contaminants.

Insulation: Insulation materials run the gamut from bulky fiber materials such as fiberglass, rock and slag wool, cellulose and natural fibers to rigid foam boards and sleek foils. Bulky materials resist conductive and, to a lesser degree, convective heat flow in a building cavity. Rigid foam boards trap air or another gas to resist conductive and convective heat flow. Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and vermiculite and perlite are also available.

Renewable Energy Technologies: Technologies that produce sustainable, clean energy from sources such as the sun, the wind, plants, and water.  These include biomass, geothermal, hydrogen, hydropower, ocean, solar energy, and wind.

Weatherization: A category of home energy upgrades which includes sealing and insulating the building envelope. Also a term used to refer to DOE’s Weatherization Assistance Program, which provides home energy upgrades to low income populations.

Weatherstripping: An energy efficiency measure that involves installing a material to seal air leaks around components that open, close and generally move (exterior doors and windows).

Whole House: A holistic view of and approach to home performance which treats the house as a system, with components including building, mechanical, environmental and occupational.

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