A standard-efficiency furnace costs $3,500 to $7,500 or more installed, and a high-efficiency unit can reach $11,500, by HomeGuide's national 2026 figures. Detroit homes add their own variables: old chimneys, gravity-era ducts, tight basements and two-family flats with two systems. We price your home after we see it.
Price ranges on this page are national figures published by HomeGuide for 2026. They are not our quotes. Your house, the equipment you choose, the venting and the ductwork move the real number up or down. Last checked October 2026.
A new furnace costs $3,500 to $7,500 or more installed for a standard-efficiency gas unit, by the national figures. HomeGuide splits that into $2,000 to $4,000 or more for the equipment and $1,500 to $3,500 or more for installation labor. High-efficiency furnaces run up to about $11,500.
No national average is published for Detroit itself, so we do not quote one. What we can say is which parts of a Detroit job tend to take time: venting changes when the old furnace used the chimney, return air that was never sized for a forced-air system, and basements where the stairs and the furnace corner are tight.
How much does a furnace cost for a 1,200 or 2,000 square foot house?
For a 1,200 square foot home, HomeGuide's range for houses of 1,000 to 1,500 square feet is $2,000 to $4,500. A 2,000 square foot home falls in its 1,500 to 2,500 square foot range of $3,000 to $6,500. These are standard installs.
| House size | National installed range |
|---|---|
| 1,000 to 1,500 sq ft | $2,000 to $4,500 |
| 1,500 to 2,500 sq ft | $3,000 to $6,500 |
| 2,500 to 3,500 sq ft | $4,000 to $9,500 |
| 3,500 sq ft and up | $5,500 to $10,000+ |
Square footage is only the start. A 1,200 square foot Detroit bungalow with an unfinished upstairs and drafty windows can need more heat than a newer, tighter house of the same size.
Is a 95% or 96% furnace worth the extra over an 80% furnace?
In Detroit, a 95% or 96% AFUE furnace usually is worth it if you plan to stay several years, because our long heating season gives the extra efficiency time to pay back. An 80% furnace wastes about a fifth of its gas up the flue. A 96% unit wastes about a twentieth.
By HomeGuide's figures, high-efficiency furnaces of 90% to 98% AFUE cost $3,800 to $11,500 or more installed, while standard 80% to 89% units sit in the $3,500 to $7,500 or more range. High-efficiency models also vent through plastic pipe out the wall, which can free the old chimney. Natural gas furnaces of 95% AFUE or more can also qualify for DTE Energy rebates, and we are a participating contractor.
What size furnace do I need?
The right size comes from a load calculation, not from the old furnace's label. HomeGuide gives a rough rule of 30 to 60 BTU per square foot, which puts a 1,500 to 2,000 square foot house anywhere from 45,000 to 120,000 BTU. That range is too wide to pick a furnace from.
A load calculation looks at the walls, the attic insulation, the windows, air leaks and the rooms. Many Detroit furnaces are oversized because the house was re-insulated after the furnace went in. An oversized furnace short-cycles, heats unevenly and wears out sooner.
How much does it cost to replace the furnace and AC together?
Replacing the furnace and AC together costs $5,000 to $11,000 nationally, with a national average of $8,000, on HomeGuide's HVAC system page. Its AC replacement page lists a furnace and AC system at $10,500 to $18,500 installed. The two pages disagree, so ask for a written quote for your house rather than leaning on either number.
Doing both at once saves a second visit, lets the indoor coil match the new outdoor unit, and keeps both on similar schedules. See our repair or replace page for when it makes sense to replace a working AC.
How much does a new HVAC system cost?
A new HVAC system, meaning a furnace and air conditioner, costs $5,000 to $11,000 as a replacement, $7,000 to $16,000 with new ductwork, and $9,500 to $18,500 with ductwork and add-ons, by HomeGuide's national figures.
| House size | National installed range |
|---|---|
| 1,000 sq ft | $3,000 to $6,000 |
| 1,200 sq ft | $3,600 to $7,200 |
| 1,600 sq ft | $4,800 to $9,600 |
| 2,000 sq ft | $6,000 to $12,000 |
| 2,500 sq ft | $7,500 to $15,000 |
| 3,000 sq ft | $9,000 to $18,000 |
What adds to the price of a furnace replacement?
Venting, gas piping, ductwork and access add the most to a furnace replacement. HomeGuide lists these extras at national prices:
- Removal of the old furnace: $50 to $200 or more.
- Permit: $50 to $300.
- Difficult access: adds 25% to 50%.
- Minor duct leak repair: $200 to $700.
- Duct changes: $25 to $55 per linear foot.
- Gas line work when converting fuel: $350 to $2,000 or more.
- Whole-home humidifier: $400 to $1,200.
In older Detroit homes, the chimney is the hidden item. When a new high-efficiency furnace stops using the chimney, the water heater may be left alone in a flue that is too large for it. That can mean a liner or a different vent, and a good quote says how it will be handled.
What should a furnace replacement estimate include?
A furnace estimate should name the furnace and list every part of the job in writing.
- The make, model, BTU size and AFUE rating.
- How the size was chosen, ideally a load calculation.
- Venting: chimney, liner or new wall vent.
- Any duct, return air or gas line changes.
- Removal and disposal of the old unit.
- The permit and the city inspection.
- Thermostat, filter rack and condensate drain.
- Which utility rebate, if any, applies to the equipment.
- Warranty registration and who does it.
Can I finance a new furnace, even with bad credit?
You can ask, but we do not publish financing terms or payment figures, and nothing on this page is a financing offer. Homeowners often use a bank or credit union loan, a home equity line, or a lender a contractor works with. Approval with bad credit depends on the lender.
Before you finance, check the low-income programs on our rebates and permits page. For owners who qualify, Michigan's State Emergency Relief program can cover repair or replacement of a furnace that does not work.
The only way to get a real price for your home is an on-site visit and a written quote. Call or text (313) 488-2188.