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- Read your nameplate
What size system do you already have?
Most residential model numbers carry the capacity in three digits. Find them on the data plate of the outdoor unit and type them in — you'll know what you have before anyone quotes you what you need.
The three digits
Examples: 018, 024, 030, 036, 042, 048, 060. They usually sit in the middle of the model number.
Nominal capacity, not measured output. What a house actually needs comes from a room-by-room load calculation.
The rest of the plate
- RefrigerantR-22 means an older system; R-410A is the common one now; R-454B and R-32 are on new equipment. It changes what a repair costs and what can be matched.
- EfficiencySEER or SEER2 for cooling, HSPF2 for heat-pump heating, AFUE on a furnace's plate.
- Volts and phase208/230V single phase at a house; three phase on many commercial units.
- MCA and MOCPMinimum circuit ampacity and maximum breaker size — what the electrician needs.
- Model and serialSerial formats differ by manufacturer; send us a photo and we'll tell you the age.
Same size isn't automatically right
A replacement is a chance to fix what was wrong. If the old system short-cycled and left the house humid, matching its size just buys the same problem again. If rooms were always short of air, the ducts need attention whatever the size.
We measure the house — windows, insulation, orientation, duct condition — and put the numbers beside the old nameplate before recommending anything.
