SEER2 and AFUE — what's actually a good efficiency number for a Kansas City home?

SEER2 rates cooling efficiency — it's the cooling output (BTUs) divided by electrical input over a seasonal test cycle. Higher is better. SEER2 replaced SEER in 2023 with stricter test conditions, so a SEER2 number is roughly 5% lower than the old SEER on the exact same unit. Don't be fooled by old marketing materials that still quote SEER.

AFUE (Annual Fuel Utilization Efficiency) rates how much of the fuel a gas furnace turns into usable heat. An AFUE of 80% means 80% of the gas you pay for goes into the house; the other 20% goes out the flue.

For heat pumps in heating mode the corresponding number is HSPF2, which also got stricter in 2023 — HSPF2 reads about 15% lower than the old HSPF on the same unit.

Here are the real "good / better / best" tiers we see installed across the Greater Kansas City service area:

• AC / SEER2: 13.4 is the federal minimum in our region. 14.3–15.2 is "good" entry-level. 16+ moves into variable-speed comfort territory. 18–20+ is premium and only pays back in homes that already have a tight envelope.
• Furnace / AFUE: 80% is standard single-stage. 90% (condensing) is the practical "good" tier for a KC home — recovers more heat from the flue gas, and the math works out on natural-gas savings within a few years. 95–98% is the high-efficiency tier; meaningful in larger or poorly insulated homes.
• Heat Pump / HSPF2: Look for 7.5+ HSPF2 for solid year-round performance. 8.5+ enters cold-climate-capable territory.

The biggest mistake we see on KC proposals — including ones we review on our Free 2nd Opinion service — is paying premium-tier SEER2 for a home that won't capture the savings. Three failure patterns:

1. Leaky ductwork. A 20-SEER2 system pushing conditioned air through ducts that lose 25% of it into the attic gives you ~15-SEER2 real-world performance. Seal the ducts first.
2. Single-stage installed where variable-speed was promised. The variable-speed compressor is what actually delivers premium SEER2's comfort and humidity control. A high-SEER2 number on a single-stage unit looks great on paper and doesn't translate to your bill.
3. Oversized equipment. A premium system that's two tons too big for your home cycles on and off too fast to ever hit its rated efficiency. Manual J load calc first, then pick the tier.

For most KC homes, the boring answer wins: 15–16 SEER2 with a properly sized two-stage AC, or 17–18 SEER2 with a variable-speed in homes where the owner is staying 10+ years and the envelope is tight. 90% AFUE for the furnace, full stop, unless the home has chronic comfort issues that justify a 95%+ modulating unit.

If a proposal is pushing you to 20+ SEER2 without addressing duct leakage, sizing, or staging — that's a number-chasing sale, not a comfort fix.

If you're comparing AC or furnace proposals and want an honest read on whether the efficiency tier you're being sold actually makes sense for your home, we'll review it free — no pressure, no script. Or browse our AC service category and heating service category for installation details.