80,000 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 · 1,085 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
16-year payback
About $2,000 more to install, saving $122 a year in gas. Inside the life of a furnace — this step is worth taking.
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
368 of 1,085
certified units are condensing (90%+ AFUE), running about $707 a year against $830 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 SLP99UH090XV60C
AFUE 99.0 · $16.97 per MMBtu to run.
Not on Amazon. Sold through installers. You can buy the filter and a smart thermostat for it yourself.
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 1,085 certified units
| Brand & model | AFUE | Input | Fuel | $/MMBtu | Buy | |
|---|---|---|---|---|---|---|
| LENNOX SLP99UH090XV60C | 99.0 | 88,000 BTU | Natural Gas, Propane Gas | $16.97 | installer | |
| FUJITSU FF98MV307017UPS | 98.3 | 70,000 BTU | Natural Gas, Propane Gas | $17.09 | installer | |
| RHEEM R98MV0703A17UPS | 98.3 | 70,000 BTU | Natural Gas, Propane Gas | $17.09 | installer | |
| LENNOX SLP99UH090XV48C | 98.2 | 88,000 BTU | Natural Gas, Propane Gas | $17.11 | installer | |
| FUJITSU FF98MV508521UPS | 98.2 | 84,000 BTU | Natural Gas, Propane Gas | $17.11 | installer | |
| RHEEM R98MV0855A21UPS | 98.2 | 84,000 BTU | Natural Gas, Propane Gas | $17.11 | installer | |
| LENNOX SLP99UH090XV36C | 98.1 | 88,000 BTU | Natural Gas, Propane Gas | $17.13 | installer | |
| ECOER EVMF98M28080B3L | 98.0 | 80,000 BTU | Natural Gas, Propane Gas | $17.14 | installer | |
| GE NF98U090M5CR | 98.0 | 88,000 BTU | Natural Gas, Propane Gas | $17.14 | installer | |
| GE NF98U090M4CR | 98.0 | 88,000 BTU | Natural Gas, Propane Gas | $17.14 | installer | |
| GE NF98U090M3CR | 98.0 | 88,000 BTU | Natural Gas, Propane Gas | $17.14 | installer | |
| AIREASE A98USMV090C12S | 98.0 | 88,000 BTU | Natural Gas, Propane Gas | $17.14 | installer | |
| COLEMAN BY JOHNSON CONTROLS CP9C080C16MP13 | 97.7 | 80,000 BTU | Natural Gas, Propane Gas | $17.20 | installer | |
| GE NF97X080V5CR | 97.5 | 80,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| GE NF97X080V4CR | 97.5 | 80,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| PHANTOM B97UR802V5CX | 97.5 | 80,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| PHANTOM B97UR802V4CX | 97.5 | 80,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| AIREASE A97US2V080C16X | 97.5 | 80,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| LENNOX SLP99DF090XV60C | 97.5 | 88,000 BTU | Natural Gas, Propane Gas | $17.23 | installer | |
| LENNOX SLP99DF090XV48C | 97.5 | 88,000 BTU | Natural Gas, Propane Gas | $17.23 | installer |
Showing the top 20 by AFUE. All 1,085 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.