HVAC & Efficiency Ratings 101

Most HVAC shopping mistakes come from comparing two systems using numbers that aren't actually comparable — an old SEER rating against a new SEER2 rating, or a ducted system's cost against a ductless system's without accounting for what each one requires structurally.

Ducted isn't always the default anymore

Multi-zone ductless mini-splits can now heat and cool an entire home, not just a single addition, and they skip duct losses entirely by not using ducts. Older homes with damaged, undersized, or absent ductwork are often better candidates for ductless than for a straightforward central-air replacement. Our ductless mini-split guide covers when each approach genuinely wins.

SEER2 and HSPF2 replaced the old ratings in 2023 — and the numbers shifted

A SEER2 rating tests under conditions closer to real installed duct static pressure than the older SEER standard did, which means a lower SEER2 number isn't automatically a step down from an older SEER-rated unit. Heat pumps carry a separate HSPF2 number for heating-mode performance. Our SEER2 ratings explained guide walks through how to compare ratings correctly across the 2023 transition.

If you're replacing a furnace, the comparison is broader than efficiency ratings

Choosing between a heat pump and a furnace-plus-AC setup depends heavily on your climate zone and your electricity-to-gas price ratio, not just on efficiency numbers. Our heat pump vs. furnace guide and full Heat Pumps 101 guide cover that broader decision.

Run the real cost comparison

Use our Heat Pump Savings Calculator to compare annual operating cost against your specific existing system rather than a generic industry estimate.