Gas Furnace Cost (2026): Installation Prices

By HomeCost Guide · Updated October 2026 · For a 1,600–2,000 sq ft home: standard gas furnace, labor, basic venting, and permits

Replacing a gas furnace costs $3,800 to $10,000 installed, with most homeowners paying around $7,000 for a standard 1,600- to 2,000-square-foot home (Angi, July 2026). That covers the furnace, labor, basic venting, and permits. High-efficiency modulating models can reach $12,000; a basic single-stage 80% AFUE swap in an easy installation can land under $5,000.

Gas brings its own cost drivers. Venting is the biggest: an 80% furnace uses metal flue pipe, but a condensing furnace (90%+ AFUE) needs PVC venting through a sidewall plus a condensate drain — retrofitting that adds $500 to $2,000. Gas line work is second: extending or upsizing a line runs $500 to $2,000, and every connection must be leak-tested and permitted. Below: equipment and installed costs by type and AFUE tier, plus the factors that actually move your quote. Angi's data also breaks costs down by furnace type and AFUE tier — single-stage, two-stage, and modulating units each carry different equipment premiums — so the sections below let you build your number from the components that apply to your home.

1. Gas Furnace Cost (2026): Installation Prices cost breakdown

Angi's equipment-only figures (single-stage $700–$3,000, modulating $1,300–$6,500) are the cost of the box before labor. Installed prices roughly double equipment cost once labor, venting, permits, and disposal are included — which is why quotes that look high for 'just a furnace' usually aren't.

Where the money goes: labor vs materials vs fees

• Labor$1,000–$2,5006–10 hours for two techs on a like-for-like swap; venting retrofits, unit relocation, or gas line upsizing pushes it higher.
• Equipment$700–$6,500The furnace itself: single-stage 80% AFUE at the bottom, modulating 96–98% with variable-speed blower at the top.
• Permits & inspection$400–$1,500Mechanical permit plus gas-pressure testing; some jurisdictions require a separate gas-piping permit.
• Removal & disposal$60–$500Hauling the old furnace, scrap recycling, old venting disposal.

Sources: Angi, HomeAdvisor, Angi, USA Today. Figures are national averages compiled from published industry data; your price will vary by home and location.

2. Signs your gas furnace needs replacing

Signs your gas furnace needs replacing

• It's 15–20 years old and facing a major repair. Past this age, repairs get frequent, efficiency lags far behind 90%+ AFUE models, and the heat exchanger is living on borrowed time.
• The heat exchanger is cracked or rusted through. It can't be safely patched, it can leak carbon monoxide, and the repair costs nearly as much as a new furnace.
• The CO detector has alarmed or a tech finds elevated CO in the flue. Odorless and deadly — immediate professional attention, usually replacement.
• Heating bills up 20–30% with no usage or rate change. A 95% AFUE replacement often pays back in 5–8 years in cold climates.
• Repairs topping $2,000 in two years, or a single quote over $1,000 past age 12. That's the economic tipping point — the money rarely comes back.

3. How a gas furnace replacement works

How a gas furnace replacement works

1. Load calculation and sizing. The contractor runs a Manual J load calculation — measuring heat loss through walls, windows, and insulation — rather than matching the old unit's BTUs. Takes 30–60 minutes on site; oversized furnaces short-cycle and die young.
2. Gas shutoff and old unit removal. Gas is shut off and the line capped, the old furnace disconnected and hauled out. Existing venting is inspected for reuse — most 80%-to-90%+ upgrades can't reuse it.
3. Venting rework. For condensing upgrades: PVC intake and exhaust through a sidewall, plus a condensate drain to a floor drain or pump. Old metal flue is removed or abandoned per code.
4. Gas connection and pressure test. New piping with sediment trap and shutoff valve, then a code-required pressure test for leaks before gas is restored. The permit inspection follows.
5. Startup, combustion check, inspection. Gas pressure, temperature rise, and combustion analysis verified; thermostat programmed; inspection card and startup paperwork filed for the warranty.

4. What affects the cost

AFUE rating: the efficiency premium

AFUE is the percentage of gas converted to usable heat. An 80% furnace wastes 20 cents of every gas dollar up the flue; a 98% modulating unit wastes almost nothing. The efficiency premium runs $1,500–$4,000 installed. In cold states with long heating seasons, gas savings can pay it back in 5–7 years. In mild climates, payback stretches past 10 years and an 80–92% unit often makes better financial sense.

Single-stage vs two-stage vs modulating

Single-stage is on-or-off — cheap ($700–$3,000 equipment) but noisy with temperature swings. Two-stage runs on low fire ~80% of the time: steadier, quieter. Modulating adjusts output continuously with a variable-speed blower for the most even heat. The jump from single-stage to modulating adds $2,500–$5,000 installed. Worth it for comfort in drafty or multi-story homes; harder to justify on payback alone.

BTU sizing and home size

Furnaces are sized in BTUs — roughly 30–60 per square foot depending on climate and insulation. Bigger isn't better: oversized units short-cycle, waste gas, and stress the heat exchanger. Equipment cost rises ~$200–$500 per 20,000-BTU step. Demand a Manual J calculation; never let a contractor size by square-foot rule of thumb or just match the old unit. An oversized furnace also never reaches steady-state efficiency, so it burns more gas per unit of heat delivered — the opposite of what the bigger number promises.

Condensing vs non-condensing venting

An 80% furnace vents 300–400°F exhaust through metal flue pipe. A 90%+ condensing furnace produces cool, acidic exhaust that must exit through PVC to a sidewall, plus a condensate drain. Retrofitting that venting adds $500–$2,000 if the old setup can't be reused — coring masonry, running PVC, adding a condensate pump. Homes with finished basements and no nearby exterior wall get the expensive version of this.

Gas line work: extension and upsizing

Same-location reconnection is usually included. Extending or upsizing gas piping runs $500–$2,000; a first-time gas service extension from the utility can add $1,000–$3,000+. Every connection must be pressure-tested and permitted — that's code, and it's why gas permits run $400–$1,500. Get the utility's answer on service extensions in writing before signing an HVAC contract. If the meter itself is undersized for the new load, the utility may swap it free or for a few hundred dollars — confirm early, since meter lead times can delay the whole project.

Ductwork condition

New equipment can't fix bad ducts. Leaky or undersized ductwork wastes 20–30% of heated air into attics and crawlspaces (ENERGY STAR). Sealing runs $500–$1,500; partial replacement $1,000–$2,700 (HomeAdvisor). If your home has chronic hot and cold rooms, budget duct fixes separately — skipping them undermines the whole investment. A two-stage or modulating furnace only delivers its comfort advantage with adequate return airflow — starved returns make premium equipment perform like basic equipment, so verify returns before upgrading tiers.

Chimney and the orphaned water heater

Upgrading to condensing venting can orphan your gas water heater in the old chimney — flue gases cool, condense, and destroy masonry from inside. The fix is a chimney liner ($1,000–$2,500) or converting the water heater to direct-vent. Ask about it explicitly; quotes that ignore it set you up for a surprise chimney repair in 3–5 years. Your contractor should address the water heater flue in the quote — if they don't mention it, ask directly, because the chimney repair it prevents costs far more than the liner.

Permits and code upgrades

The permit can trigger code upgrades: a disconnect within sight of the unit, adequate combustion air, a condensate overflow switch, CO detectors. Each runs $75–$300; together they can add $500–$1,500 on older homes. Anyone offering a cash discount for no permit is cutting the one corner that protects you from gas leaks — and voiding your warranty and insurance coverage.

5. Saving money & hiring right

Questions to ask your contractor

• Will you run a Manual J load calculation, and can I see the results before you size the unit?
• Is this a condensing unit — what venting changes does my home need, and what happens to my water heater's flue?
• What's included for the gas line, and is the pressure test plus permit in your price?
• What commissioning do you perform at startup — and do I get the readings in writing?
• What's the parts warranty versus your labor warranty, and who honors it?

6. How costs vary by state

Furnace costs track local labor rates and heating demand. Below: Angi's $3,800–$10,000 national range adjusted for regional labor — realistic planning numbers, not contractor surveys. Your local quotes are the final word.

7. Frequently asked questions