Glossary of Terms
As you learn more about your home’s heating and cooling system, you may come across terms or acronyms that aren’t immediately familiar. This glossary is designed to help you better understand the most common HVAC terminology—so you can make more informed decisions about your home comfort.
A
AC (Air Conditioner)
Typically refers to the outdoor unit that removes heat from your home to keep it cool.
AHRI
An industry organization that certifies HVAC equipment performance and efficiency standards.
B
BTU
A unit of heat measurement used to define heating and cooling capacity.
BTU/hr
Measures how much heating or cooling a system delivers over time.
C
Capacity
The amount of heating or cooling an HVAC system can provide.
D
DOE
The federal agency that sets HVAC efficiency standards.
E
Efficiency
How effectively your system converts energy into heating or cooling.
G
GWP
A measure of how much a gas contributes to warming compared to CO₂.
H
HVAC
Heating, ventilation, and air conditioning systems that control indoor comfort.
I
IEER
Measures efficiency across varying operating conditions.
M
M1
A newer DOE testing method designed to reflect real-world performance.
N
NATE
A certification organization that validates HVAC technician expertise.
R
Refrigerant
The substance used to transfer heat in your HVAC system.
S
SEER2
A key rating that measures cooling efficiency.
T
Ton
A unit of cooling capacity equal to 12,000 BTUs.
Z
Zoning
Dividing your home into areas to control temperature independently.
