Guide
Gas furnaces in 2026
Last reviewed 2026-05-01 · ~10 min read
If your furnace is approaching the end of its life, you face a real choice in 2026: replace it with another gas furnace, or switch to a heat pump that does both heating and cooling. This guide covers what a furnace replacement actually costs by efficiency tier, the federal rule that changed which efficiencies you can even buy, and when the heat-pump alternative makes more sense — financially and otherwise.
How a gas furnace actually works
A gas furnace burns natural gas (or propane in rural areas without a gas line) inside a sealed heat exchanger. A blower pulls return air across the hot heat exchanger and pushes it into your ducts. The combustion products — primarily water vapor and carbon dioxide — vent outside through a flue. Efficiency depends on how much of the fuel’s heat content ends up in your ductwork instead of going up the flue.
That efficiency is measured as AFUE, the Annual Fuel Utilization Efficiency. An 80% AFUE furnace converts 80% of the fuel’s energy to useful heat and loses 20% out the flue. A 95% AFUE furnace recovers nearly all the heat from the exhaust gases — it’s called a “condensing” furnace because the exhaust cools enough that water vapor condenses into liquid, which drains away. That extra heat recovery is the difference between a 1980s-style metal flue and a modern unit that vents through PVC pipe.
The DOE 2024 rule changed what you can buy
In December 2023, the U.S. Department of Energy finalized a rule requiring all new residential gas furnaces sold or installed in the northern US to meet 95% AFUE or higher, with a compliance date in May 2028. Several major manufacturers (Carrier, Trane, Lennox, Goodman) have already stopped 80% AFUE production for non-mobile-home applications. If you’re in the northern half of the country and shopping for a furnace in 2026, your realistic choices are 95% single-stage, 96–97% two-stage, or 97–98% modulating units.
In the southern US, where heating loads are smaller, 80% AFUE remains available. The cost difference between 80% and 95% AFUE is real — roughly $1,000–$1,500 in equipment cost plus another $500–$1,000 in venting work because condensing furnaces need PVC venting and a condensate drain. The payback on that premium depends on your gas rate and how much you actually heat. In Texas or Florida, the payback is rarely under 15 years.
What a gas furnace actually costs installed in 2026
National installed-cost ranges based on Modernize, HomeAdvisor, and contractor association data:
- 80% AFUE single-stage (60–100k BTU): $3,500–$6,000 installed. Cheapest option, southern US only.
- 95% AFUE single-stage (most common in 2026): $4,500–$8,500 installed.
- 97% AFUE two-stage / variable: $5,500–$9,500 installed.
- 98% AFUE modulating (5:1 turndown): $6,500–$11,000 installed.
State labor cost is the biggest variable. The same equipment installed in Massachusetts often costs 30% more than in Tennessee, primarily because of HVAC labor rates and stricter permitting.
The hidden cost: venting + electrical
If you’re replacing an 80% AFUE furnace with a condensing 95%+ unit, you can’t reuse the existing flue. Condensing furnaces require PVC venting (the exhaust isn’t hot enough to drive a natural draft) and a condensate drain. Budget $300–$800 for new venting in a straightforward install, more if the unit is in a closet or attic without easy run paths. Most furnaces also draw a 15–20A 120V circuit; if your panel is full, that’s another $300–$1,500 for a sub-panel or load shed.
Sizing — the chronic mistake
Most American furnaces are oversized by 20–40%. The contractor’s shortcut is to “match the old one” or use a rough per-square-foot rule. The correct approach is a Manual J load calculation (ACCA standard) that accounts for your home’s actual insulation, air leakage, windows, orientation, and climate. An oversized furnace short-cycles — it runs in 5-minute blasts, never reaches steady state, doesn’t dehumidify well, and shortens its own life through thermal cycling. Ask any quote to include the Manual J. If the contractor can’t produce one, walk.
Lifespan and brand reliability
ASHRAE’s service-life data puts a residential gas furnace at 15–20 years on average. Heat exchangers are the failure point. Once a heat exchanger cracks, the furnace must be replaced — refusing risks combustion gases (including carbon monoxide) entering the supply air. Annual maintenance, especially keeping the burner clean and the heat exchanger inspected, materially extends life.
Brand reliability data from Consumer Reports and contractor surveys consistently puts Trane, American Standard, Carrier, and Lennox at the top tier for parts availability and service life. Bryant (Carrier’s mid-tier sister) and Rheem are solid value picks. Goodman, Amana, and Daikin (same manufacturer) have improved significantly since the 2010s and now offer some of the longest warranties (12+ years on heat exchanger). Avoid no-name imports for permanent installs — warranty service is essentially nonexistent.
Federal incentives in 2026: there aren’t any
This is the most important change to understand. The federal 25C credit, which once covered 95%+ AFUE gas furnaces at 30% of cost up to $600, expired December 31 2025 (OBBBA, signed July 4 2025). There is no federal subsidy for a gas furnace replacement in 2026. The HEEHRA / DOE Home Energy Rebates program is electric-only by statute — gas equipment does not qualify.
State and utility programs are uneven. Some gas utilities (Nicor Gas in Illinois, Peoples Gas in Chicago, ConsumersEnergy in Michigan) still offer $200–$600 rebates on 95%+ AFUE installs. Check your utility’s residential efficiency rebate page. National Grid, Eversource, NSTAR, and others in the Northeast generally do not subsidize new gas equipment anymore as policy shifts toward electrification.
When the heat-pump alternative makes more sense
This is the conversation worth having. In 2026, a heat pump replacement is on the same order of cost as a premium furnace install — $8,000–$15,000 for ducted central heat pump versus $6,500–$11,000 for a premium furnace. The heat pump replaces your AC too (so the comparison is heat pump alone vs furnace + new AC if AC is also aging). And state heat-pump rebates often subtract $1,000–$10,000 from the heat-pump number where furnace rebates have largely disappeared.
Operating-cost math: a cold-climate heat pump cuts heating energy use about 60% versus an 80% AFUE gas furnace and 50% versus a 95% AFUE furnace. Whether that translates to dollar savings depends on your electricity rate vs gas rate. The crossover formula: heat pump wins when (electricity cents per kWh × 29.3) is less than ($/therm of natural gas) ÷ 2.5. In states with cheap electricity (WA, OR, ID, KY) and average gas rates, heat pump is a clear winner. In high-electricity / low-gas states (MA, CT, CA), the margin narrows but doesn’t disappear, mainly because heat pumps also do summer cooling.
The maintenance you should do regardless
Annual professional inspection of the heat exchanger and burner, especially for units 10+ years old. Filter changes every 1–3 months for one-inch filters; quarterly for four-inch deep-pleat filters. Keep the area around the furnace clear — no stored items within 18 inches. Check that the condensate drain is flowing (95%+ units only); a clogged drain triggers shutoff. Install carbon monoxide detectors on every floor — not optional with any combustion appliance.