HVAC Glossary of Terms
a | b | c | d | e | f | g | h | i | j | k | l | m | n | o | p | q | r | s | t | u | v | w | x | y | z
- Heat
- A form of thermal energy resulting from combustion, chemical reaction, friction, or movement of electricity. As a thermodynamic condition, heat, at a constant pressure, is equal to internal or intrinsic energy plus pressure times volume.
- Heat Loss
- The heat that flows from the building interior, through the building envelope to the outside environment.
- Heat Rate
- The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net kilowatt-hour.
- Heat Register
- The grilled opening into a room by which the amount of warm air from a furnace can be directed or controlled; may include a damper.
- Heating Capacity (Also Specific Heat)
- The quantity of heat necessary to raise the temperature of a specific mass of a substance by one degree.
- Heating Degree Day(s) (HDD)
- The number of degrees per day that the daily average temperature (the mean of the maximum and minimum recorded temperatures) is below a base temperature, usually 65 degrees Fahrenheit, unless otherwise specified; used to determine indoor space heating requirements and heating system sizing. Total HDD is the cumulative total for the year/heating season. The higher the HDD for a location, the colder the daily average temperature(s).
- Heating Load
- The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.
- HEPA
- High efficiency particulate arrestance (filters).
- Home Energy Rating Ssystems (HERS)
- A nationally recognized energy rating program that gives builders, mortgage lenders, secondary lending markets, homeowners, sellers, and buyers a precise evaluation of energy losing deficiencies in homes. Builders can use this system to gauge the energy quality in their home and also to have a star rating on their home to compare to other similarly built homes.
- Hot Air Furnace
- A heating unit where heat is distributed by means of convection or fans.
- Humidifier
- A device for increasing the humidity in a room or home.
- Humidity
- A measure of the moisture content of air; may be expressed as absolute, mixing ratio, saturation deficit, relative, or specific.
- HVAC
- HVAC is an acronym for heating, ventilation, and air-conditioning system.