140,000 BTU furnaces
Every certified furnace at this input rating, gas and oil, ranked by AFUE — the share of fuel that becomes heat in the house.
Data current as of July 12, 2026 · 256 certified units · source AHRI + ENERGY STAR
Which efficiency tier is worth buying at this size?
Furnace installed cost tracks the efficiency tier, not the size — so the decision at any input rating is which tier to buy, and there are two steps. Running costs below come from the certified units at this size over a 40 MMBtu season, the default our operating-cost calculator uses.
Step 1 · 80% → condensing
24-year payback
About $2,000 more to install, saving $83 a year in gas. Longer than a furnace lasts.
Step 2 · condensing → modulating
Never
Another $2,750 to install for $14 a year. The gas saving is nearly nothing because the first step already captured it — buy this tier for quiet, even heat and better humidity control, not for the bill.
At this size
23 of 256
certified units are condensing (90%+ AFUE), running about $707 a year against $790 for the 80% band.
Install bands are US national typical for a like-for-like swap, compiled 2026-07-16; a condensing furnace also needs new PVC venting and a condensate drain, which is part of why the step costs what it does. Gas cost per MMBtu is computed from certified AFUE and EIA average prices — see our methodology.
Highest AFUE in this group
LENNOX SLP99UH135XV60D*
AFUE 98.4 · $17.07 per MMBtu to run.
See installed costs →AFUE is the share of fuel a furnace turns into heat in your home. 96% AFUE wastes 4 cents of every dollar.
Every unit here is the same input rating, so the ranking is efficiency at a fixed size. Sizing is a heat-loss calculation, not a rule of thumb — a bigger furnace short-cycles rather than heating better.
The 20 highest-AFUE of 256 certified units · 1 with a verified place to buy
| Brand & model | AFUE | Input | Fuel | $/MMBtu | Buy | |
|---|---|---|---|---|---|---|
| LENNOX SLP99UH135XV60D* | 98.4 | 132,000 BTU | Natural Gas, Propane Gas | $17.07 | Get quotes | |
| GE NF98U135M5DR | 98.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.14 | Get quotes | |
| AIREASE A98USMV135D20S*-* | 98.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.14 | Get quotes | |
| LENNOX ML297UH135XV60D* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| GE NF97U135T5DR* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| KEPLER 97G2UH135DV20*-* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| GE NF97U135V5DR | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| COMFORT-AIRE GUH97T135D5MP | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| AIREASE A97US2V135D20S* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| LENNOX EL297UH135XE60D* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| LENNOX EL297UH135XV60D* | 97.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.32 | Get quotes | |
| KEPLER 96G1UH135DE20* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| GE NF96U135S5DR* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| COMFORT-AIRE GUH96C135D5MP* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| PHANTOM B96UR1351E5D* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| AIREASE A96UH1E135D20S* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| LENNOX ML196UH135XE60D* | 96.0 | 132,000 BTU | Natural Gas, Propane Gas | $17.50 | Get quotes | |
| ACIQ N96MSN1402422A | 95.0 | 140,000 BTU | Natural Gas, Propane Gas | $17.68 | Buy | |
| WEATHERMAKER PG96MSAA66140D | 95.0 | 140,000 BTU | Natural Gas, Propane Gas | $17.68 | Get quotes | |
| BRYANT 916SA66140M24*D | 95.0 | 140,000 BTU | Natural Gas, Propane Gas | $17.68 | Get quotes |
Showing the top 20 by AFUE. All 256 certified units in this group are filterable in the full database — we rank here rather than dump, because a table nobody can read is not a resource.
Capacity and efficiency are AHRI-certified values; $/MMBtu is computed by us from EIA energy prices — see methodology. Input rating is the fuel the burner consumes; output is lower by exactly the AFUE.