HVAC equipment
Residential HVAC equipment comes in a few families: a furnace (burns gas, oil or propane, or uses electric resistance) for heat, a central air conditioner for cooling, a heat pump that does both by moving heat rather than making it, and ductless mini-splits for homes or rooms without duct work. Since January 1, 2023, efficiency is rated using SEER2, EER2 and HSPF2 under a revised DOE test procedure.
SEER2 replaced SEER because the old test understated real-world conditions. The M1 test procedure raises external static pressure five-fold, from 0.1 to 0.5 inches of water, to better reflect how equipment actually performs once it is connected to real ductwork. That is why a SEER2 number looks lower than the old SEER number for comparable equipment - it is a harder test, not worse equipment.
Minimum standards are set federally and vary by region for air conditioners, while heat pump minimums are national: split-system heat pumps must meet 14.3 SEER2 and 7.5 HSPF2, and single-package heat pumps 13.4 SEER2 and 6.7 HSPF2. Confirm the regional AC minimum for your state with your contractor or the manufacturer's regional compliance information.
New equipment is also in the middle of a refrigerant change. Lennox notes it is moving whole-home systems to R-454B and ductless to R-32, and that these refrigerants are not interchangeable with R-410A. Existing R-410A systems can keep being serviced, but supply of the old refrigerant is expected to tighten. That matters if you're deciding whether to nurse an old system along.
Choosing HVAC equipment
The judgement calls that decide the bill, before anyone quotes you.
- Size is more important than brand or efficiency tier ACCA Manual J determines the load, Manual S selects the equipment, Manual D designs the ducts. Skipping these is the single most common cause of an expensive system that doesn't feel good.
- Heat pump or furnace depends on your climate and your electricity price A heat pump moves heat instead of generating it, so it can heat and cool with one machine. Whether it beats a gas furnace on running cost depends entirely on local gas and electricity rates - ask for a side-by-side operating cost estimate.
- Mini-splits are for homes without usable ducts They're excellent for additions, garages, converted attics and old houses with no duct chases. They are usually not the cheapest answer if you already have good ductwork.
- Match the indoor and outdoor unit Replacing only the outdoor condenser and keeping a mismatched indoor coil can cost you the rated efficiency you paid for. Ask for the AHRI-matched system reference on the quote.
- Ask which refrigerant the quoted system uses It affects future service and line-set compatibility. Get it in writing on the proposal.
All HVAC equipment
Central Air Conditioner
Gas Furnace
Electric Furnace
Air Source Heat Pump
Ductless Mini Split
Geothermal Heat Pump
Air Handler
Smart Thermostat
Where these figures come from
Sources last checked
- SEER2.com - About SEER2 and regional standards · retrieved 2026-07-25
- Lennox - New HVAC Refrigerant 2025 · retrieved 2026-07-25
- ACCA - Technical Manuals · retrieved 2026-07-25
- Carrier - How Long Do HVAC Systems Last? · retrieved 2026-07-25
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