This is a list of commonly used terms that might be used in discussion about your home’s energy efficiency.

Air barrier - Any part of a building that resists the passage of air to the outside.

Air sealing - The process of finding or anticipating air leakage and reducing or eliminating it.

Blower door - Device that uses a fan and gages to measure and locate air leaks.

BTU - British Thermal Unit. Energy needed to raise the temperature of one pound of water one degree.

Carbon monoxide - an odorless and deadly gas that results from incomplete combustion.

CFM - Cubic Feet per Minute. Used to measure amount of airflow

Convection - Transfer of heat by the movement of fluid such as water or air.

Duct work - A series of pipes or channels that carry conditioned air through the home.

Energy Rater - Person certified to issue the Energy Star certification to a home.

ENERGY STAR - (home) Classification for homes that have scored 86 or higher on the HERS scale, and at least 15% higher than local building standards.

HERS - Home Energy Rating System

HVAC - Heating Ventilation Air Conditioning

Ice dam - Water from melted snow that runs down the roof and freezes close to the gutters, causing damage to the interior of the home during a thaw.

Infiltration - The inflow or outflow of air through breaches in the thermal envelope

Insulation - Material used to slow the transfer of heat energy.

IR scanner - Device that uses infrared energy to display a visual image of temperature variations.

Make up air - Air supplied to replace exhausted or vented air.

Pascal - Unit of measurement of air pressure.

Relative humidity - The percent of moisture absorbed in the air compared to the maximum amount possible.

Retrofit - An energy conservation measure that is applied to an existing building.

Return air - Air returning to the furnace to be heated before being supplied to the rooms.

R-value - Numerical value given to a material based on resistance heat energy transfer.

Space conditioning - Heating, cooling or ventilation of an indoor space.

Supply air - Air that has been heated or cooled and then sent through ducts to the rooms.

Thermal envelope - The barrier that separates inside conditioned air from outside unconditioned air.