Glossary of Applied Air HVAC Terminology

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
EER (Energy Efficiency Ratio)
A ratio calculated by dividing the cooling capacity in Btu's per hour (Btuh) by the power input in watts at any given set of rating conditions, expressed in Btuh per watt (Btuh/watt). EER & SEER can not be compared equally.  EER changes with the inside and outside conditions, falling as the temperature difference between inside and outside gets larger.
Efficiency
A rating on comfort equipment is similar to the miles per gallon rating on your car.
Energy Recovery Ventilator (ERV)
This device preheats incoming outside air during the winter and pre-cools incoming air during the summer to reduce the impact of heating and or cooling the indoor air.
EPA (Environmental Protection Agency)
Environmental Protection Agency - http://www.epa.gov/
Evaporation
The condition that occurs when heat is absorbed by liquid and it changes to vapor.
Evaporator Coil
Part of a split-system air conditioner or heat pump located indoors. The evaporator coil cools and dehumidifies the air by converting liquid refrigerant into a gas, which absorbs the heat from the air. The warmed refrigerant is then carried through a tube to the outdoor unit (condenser coil).
Exfiltration
Uncontrolled air leakage out of a building.
Exhaust
The air flow leaving the treated space.