Furnace and AC replacement cost calculator
HOW MUCH DOES A NEW FURNACE AND AC COST?
HomeGuide puts replacing a furnace and AC unit at $5,000 to $11,000, or about $3 to $6 per square foot of home, with an average of $8,000. New ductwork raises it to $7,000 to $16,000. In Seattle, Angi lists $5,555 to $13,888 for a furnace and AC replacement, with an average of $8,333. Enter your home below for your range.
How the calculator works
- Furnace and AC. Your home's size is multiplied by HomeGuide's $3–$6 per square foot for a new furnace, AC unit and installation, using your existing ductwork. HomeGuide calls this a change-out and says it typically takes one day.
- With new ductwork. HomeGuide gives a flat $7,000–$16,000, so home size isn't used. It says installation with ductwork takes 3 to 5 days.
- Furnace only. HomeGuide's $2,000–$5,400 to replace a furnace.
- Central AC only. HomeGuide's installed price for the AC size you pick.
- Seattle. Angi's Seattle range of $5,555–$13,888 is for a furnace and AC replacement. Angi's Seattle page doesn't give separate furnace-only or AC-only prices, so none are shown for those jobs.
- Extras. Angi says Seattle permit fees for a standard split system average $95.90. Sales tax is added at Seattle's 10.55% rate if you tick the box, because Washington contractors collect sales tax on the whole contract, labor included (Department of Revenue).
Rates used
| Job | U.S. (HomeGuide) | Seattle (Angi) |
|---|---|---|
| Furnace and AC replacement | $5,000–$11,000 ($3–$6/sq ft) | $5,555–$13,888 |
| With new ductwork | $7,000–$16,000 | not listed |
| With ductwork and add-ons | $9,500–$18,500 | not listed |
| Furnace only | $2,000–$5,400 | not listed |
| Central AC only | $2,500–$7,500 | not listed |
| AC size | BTU | AC system installed (HomeGuide) |
|---|---|---|
| 1.5 tons | 18,000 | $2,000–$5,000 |
| 2 tons | 24,000 | $2,500–$5,500 |
| 2.5 tons | 30,000 | $2,700–$6,000 |
| 3 tons | 36,000 | $3,000–$6,500 |
| 3.5 tons | 42,000 | $3,100–$7,000 |
| 4 tons | 48,000 | $3,500–$7,500 |
| 5 tons | 60,000 | $4,000–$8,000 |
Seattle prices by system
| System | Seattle (Angi) |
|---|---|
| Split system (furnace and outdoor AC) | $4,200–$8,350 |
| Hybrid (heat pump with a gas furnace backup) | $2,800–$11,100 |
| Duct-free | $2,200–$16,100 |
| Packaged heating and air | $11,100–$15,550 |
Thinking about a heat pump instead of a new AC? See our heat pump installation cost in Seattle guide, which covers City Light and PSE rebates, or mini split installation cost for homes without ducts.
Before you sign
- Ask for the size of the new units and how it was chosen. A load calculation is more reliable than matching the old unit.
- HomeGuide says a change-out only makes sense if the ductwork is in excellent condition, and that ductwork lasts 10 to 20 years. Ask the installer to check it.
- Ask who pulls the permit and whether it's in the price.
- Look the contractor up on L&I's Verify a Contractor tool. For jobs of $1,000 or more on a home, the contractor must give you a written disclosure statement before work starts (RCW 18.27.114).
Frequently asked questions
How much does a new furnace and AC cost?
HomeGuide puts it at $5,000 to $11,000, or $3 to $6 per square foot of home, with an average of $8,000. With new ductwork it's $7,000 to $16,000. In Seattle, Angi lists $5,555 to $13,888, with an average of $8,333.
How much does a furnace and AC cost for a 2,000 sq ft house?
HomeGuide lists $6,000 to $12,000 to replace the HVAC system in a 2,000 square foot home.
Is it cheaper to replace the furnace and AC at the same time?
Separately, HomeGuide lists $2,000 to $5,400 for a furnace and $2,500 to $7,500 for a central AC, which together can add up to more than its $5,000 to $11,000 for both at once. Ask installers to quote both ways.
Do I need a permit to replace a furnace in Seattle?
Angi says Seattle requires permits for heating and cooling equipment, and that fees for a standard split system average $95.90. Your HVAC contractor usually pulls the permit.
Why doesn't the calculator ask for my address or phone number?
It doesn't need them. The math runs in your browser, and nothing you enter is sent anywhere or stored.
Sources
- HomeGuide — How Much Does a New HVAC System Cost to Install or Replace? (August 27, 2025)
- Angi — Furnace and AC replacement cost in Seattle, WA (updated Apr 14, 2026)
- Washington Department of Revenue — Custom construction; Seattle rate change, January 1, 2026
- RCW 18.27.114 and L&I — Hiring a contractor
All sources accessed October 14, 2026.
This calculator gives a rough range from published average rates. It is not a quote and can't size your system. Gas and electrical work is dangerous; hire a licensed HVAC contractor. Nothing you enter is sent anywhere or stored. See our disclosure and disclaimer.