The three published figures
| Source | Range | Average |
|---|---|---|
| Fixr, January 2025 | $4,000 to $8,000 | $6,000 |
| This Old House, April 2026 | not stated separately | $6,900 |
| Bob Vila, January 2024 | $3,800 to $10,000 | not stated for gas |
$900 between the two averages, our subtraction, from guides fifteen months apart. Bob Vila's range brackets both. Fixr adds a low end of $3,000 and a high end of $12,000.
That is unusually close agreement by the standards of this section. Our furnace page found three averages remarkably close together for furnaces generally, and this is the gas-specific version of the same picture.
Where the money actually goes
Fixr prices the furnace itself, separately from the job:
| Type of gas furnace | Materials only |
|---|---|
| Single-stage | $500 to $1,700 |
| Two-stage | $700 to $2,700 |
| Modulating | $1,200 to $3,500 |
Our arithmetic, marked as ours, and this is the number worth taking away. Against an installed average of $6,000, a mid-range two-stage furnace at roughly $1,700 is about 28% of the bill. Even the dearest modulating unit at $3,500 is well under 60%.
So on a gas furnace, the majority of what you pay is not the furnace. It is labour, flue work, gas and electrical connections, and whatever the existing ducting needs. That is why two quotes for the same model can differ by thousands, and why asking for the equipment price separately is the single most useful question on this page.
What the three stage types actually buy
Fixr describes them plainly:
- Single-stage was the first type ever produced and is still used, running at one output.
- Two-stage has high and low blower settings, so it can cycle on a lower setting.
- Modulating is among the most efficient, often reaching 98% efficiency or higher.
On efficiency, Fixr sets the bands: a furnace is high-efficiency at 90% or above, and standard at 80% to 89%.
Our reading, marked as ours. The stage type and the efficiency rating are not the same thing, though they correlate. What the higher stages buy you is steadier temperature and quieter running, with efficiency as a consequence. If someone is selling you a modulating furnace purely on fuel savings, ask for the AFUE figures of both options and do the arithmetic on your own gas bill, because the comparison depends on what you burn and what you pay for it.
The line item people forget
Bob Vila names it: if a gas line has to be added, that is $500 to $2,000, plus a gas line permit at $50 to $200.
Our note: this applies when you are switching to gas rather than replacing a gas furnace with another. If you are already on gas, it should not appear on your quote, and if it does, ask what is being replaced and why.
Against the alternatives
Bob Vila's fuel table, which our furnace page uses in full:
| Fuel | Bob Vila's installed range |
|---|---|
| Electric | $2,000 to $7,000 |
| Natural gas | $3,800 to $10,000 |
| Oil | $6,750 to $10,000 |
This Old House orders them the same way: electric is the most affordable at $2,000 to $7,000 and oil the most expensive.
Our reading. Gas sits in the middle on purchase price and is usually the cheapest to run in most of the US, which is the reason it is the common choice rather than the cheap one. Our electric furnace page sets out why the cheapest furnace to buy is rarely the cheapest to own, our propane furnace page and oil furnace page price the other two fuels, and our heat pump vs furnace page prices the option that does cooling as well.
What the brand changes
Fixr prices seven brands, materials only, and the spread is narrower than people expect:
| Brand | Materials only |
|---|---|
| Rheem | $800 to $1,500 |
| Ruud | $800 to $2,000 |
| Bryant | $800 to $2,500 |
Fixr notes that Ruud is made by the same company as Rheem and shares many parts and casings, and that Bryant is a Carrier subsidiary sharing parts and casings with most Carrier furnaces.
Our reading, marked as ours: on a bill where the equipment is under a third of the total, choosing between two brands that share a factory is not where your money is decided. The installer is.
Before you get quotes
- Ask for the equipment price and the labour separately. At roughly 28% of the bill, the furnace is the part you can compare across quotes.
- Ask which stage type is quoted, single, two-stage or modulating. They are different products at the same heading.
- Ask for the AFUE figure, not just "high efficiency". The band starts at 90%.
- If you are switching to gas, add $500 to $2,000 for the line plus the permit before comparing against your current fuel.
- Ask what ducting work is included. It is in the two thirds of the bill that is not the furnace.
Sources
- Fixr, Cost to Install a Gas Furnace, updated January 31, 2025 (the $4,000 to $8,000 range and $6,000 average, the $3,000 low and $12,000 high, prices by stage type, the efficiency bands, and the brand table)
- This Old House, How Much Does a Furnace Cost?, updated April 3, 2026 (the $6,900 average for natural gas furnaces, and the comparison against electric and oil)
- Bob Vila, How Much Does Furnace Replacement Cost?, updated January 31, 2024 (the $3,800 to $10,000 range for gas, the fuel comparison table, the gas line addition and the permit cost)
Price figures are national US ranges from the sources above as of the date shown. Your local price depends on labor rates, permits and site conditions. Read how we get our numbers.