Lifespan by system
| Equipment | Useful life (Fannie Mae) | ENERGY STAR: consider replacing after |
|---|---|---|
| Furnace, gas or electric (with A/C) | 20 years | 15 years |
| Boiler (in-unit) | 25 years | 15 years |
| Central A/C outdoor condenser | 20 years | 10 years |
| Heat pump condensing unit (one dwelling) | 15 years | 10 years |
| Window or through-wall A/C | 10 years | (not given) |
Fannie Mae's figures are "standardized average estimated useful life" values from its 2019 property-inspection tables, written for apartment buildings and meant to be adjusted for maintenance and climate. ENERGY STAR's ages are the point at which it suggests pricing a replacement, not the point at which equipment fails. The gap between the two columns is the window in which a repair-or-replace call gets made.
The signs, from ENERGY STAR
ENERGY STAR lists these as reasons to consider a replacement:
- The heat pump or air conditioner is more than 10 years old; the furnace or boiler more than 15.
- "Your equipment needs frequent repairs and your energy bills are going up."
- Some rooms are too hot or too cold.
- The home has humidity problems or excessive dust.
- The system is noisy, which can mean "an undersized duct system or a problem with the indoor coil".
It adds that new high-efficiency equipment, "installed correctly", can save up to 20 percent on heating and cooling costs.
What a replacement is filed at
| City | HVAC permits (3 years) | Usual filed value | Middle half of firms' usual job | Usual days, issue to final | Reached final |
|---|---|---|---|---|---|
| Sacramento County, CA | 7,937 | $15,268 | $10,000–$15,950 | 56 | 84.1% |
| Elk Grove, CA | 4,434 | $16,000 | $11,775–$16,906 | 50 | 84.7% |
| Marin County, CA | 1,640 | $13,261 | $14,000–$19,250 | 96 | 74.8% |
| Cary, NC | 9,909 | $9,891 | $7,900–$11,693 | 29 | 77.9% |
| Cape Coral, FL | 5,015 | $8,570 | $6,750–$9,170 | 41 | 93.2% |
| Miami, FL | 5,161 | $6,792 | $5,250–$10,000 | 73 | 95.6% |
| Cleveland, OH | 4,916 | $5,706 | $4,000–$10,845 | 142 | 80.8% |
| Seattle, WA (furnace & heating) | 18,668 | $7,550 | $6,500–$14,000 | 66 | 86.2% |
Seattle files heat pumps separately: 15,441 heat pump and AC permits, usually filed at $8,000, against 18,668 furnace and heating permits at $7,550. Replacements cluster in the season the equipment is needed: Seattle's heat pump permits peak in June (index 130, where 100 is an average month) and bottom out in January. Pricing a replacement before the old unit fails lets you book outside the peak.
Repair or replace
| Situation | Usually |
|---|---|
| AC or heat pump under 10 years, one part failed | Repair |
| AC or heat pump over 10 years with rising bills and repeat repairs | Price a replacement (ENERGY STAR) |
| Furnace under 15 years, one part failed | Repair |
| Furnace over 15 years, or rooms that will not heat evenly | Price a replacement (ENERGY STAR) |
The filed costs and Bay Area furnace rules are in our HVAC repair vs replacement guide; city-by-city prices are in HVAC replacement cost. If you are choosing between a furnace and a heat pump, see what a heat pump is.
Check a replacement quote in five minutes
- Read the install date on the outdoor unit's or furnace's rating plate, and compare it with the table above.
- Compare the quote with your city's middle-half range in the filed-value table.
- On your city's HVAC compare page (for example Sacramento County), check the contractor's permit count and finished share, and ask whether the permit is in the price.
See every Sacramento County HVAC contractor's permits →
What this does not tell you
Permits do not record the age of the equipment removed, so we cannot measure how long systems last in these cities; the lifespans come from Fannie Mae and ENERGY STAR. Repairs are not permitted, so there is no filed repair price. The filed value mixes furnaces, air conditioners and heat pumps in most cities, and is the contractor's own figure.
How we know this
HVAC permits are those each city files under a heating, cooling or mechanical work type in its three-year window ending September 2026. The usual filed value is the median of permits that carry one; the middle-half range uses firms with three or more permits; days is the median from issue to final; "reached final" is the share of permits a year or more old that the city closed with a final. Lifespans are from Fannie Mae's Appendix F and the replacement ages and signs from ENERGY STAR, read 22 October 2026.
Numbers come from Sacramento County building permits on single-family, duplex and townhouse homes in the unincorporated county (the County's Accela permit layer); City of Seattle (SDCI) building, trade and electrical permits on single-family and duplex homes (the city's open-data exports); Town of Cary building permit applications (issued permits only); City of Miami building permits (since 2014); City of Cape Coral building permits (the city's open permit table starts January 2025); City of Elk Grove TRAKiT building permits on single-family, duplex, mobile-home and ADU homes; City of Cleveland building permits; Marin County Community Development Agency building permits on homes in unincorporated Marin (the County's open-data permit and inspection files), data through October 17, 2026. Nobody paid to be on this page and nobody can.
Questions
- How long do traditional HVAC systems last?
Fannie Mae's useful-life tables give a gas or electric furnace with A/C 20 years, an outdoor condenser 20 years and a window or through-wall A/C 10 years. ENERGY STAR's rule of thumb is shorter: consider replacing a furnace or boiler at more than 15 years and an air conditioner at more than 10.
- How long should a heat pump last?
About 15 years. Fannie Mae's table for equipment serving a single dwelling puts a heat pump's condensing unit at 15 years (20 for central plant), and ENERGY STAR suggests considering replacement once a heat pump is more than 10 years old.
- How to tell if you need to replace your HVAC system?
ENERGY STAR's signs: the heat pump or AC is more than 10 years old or the furnace or boiler more than 15, it needs frequent repairs while energy bills rise, some rooms are too hot or too cold, the home has humidity or dust problems, or the system is noisy.
- When to replace an air conditioner?
ENERGY STAR says to consider it once the unit is more than 10 years old, or sooner if it needs frequent repairs and bills are climbing. A replacement HVAC job was usually filed at $9,891 in Cary and $6,792 in Miami.
- When to repair an air conditioner?
When it is younger than about 10 years (ENERGY STAR's replacement age for an AC) and one part has failed. Repairs usually need no permit, so there is no filed repair price; compare the repair quote with the replacement figures above.
- Is there a federal tax credit for a new HVAC system in 2026?
No. The IRS says the energy efficient home improvement credit (25C) is not allowed for property placed in service after December 31, 2025.
Build your own list
Every firm with that kind of permit on record. Pick what you value. The list moves.
Related guides
- Hiring an HVAC contractor: 5 red flags and 10 questions, checked against HVAC permits in 43 cities
- How to finance a roof, heat pump or solar: FHA, USDA, PACE and state loans compared
- Repair or replace your furnace or AC? The filed costs and the rules
- How many contractor quotes should you get? Three, and how to tell if they're in range
For one city
- When is it time to replace? — ENERGY STAR (U.S. EPA) (accessed 2026-10-22)
- Instructions for Performing a Multifamily Property Condition Assessment, Appendix F: Estimated Useful Life Tables (Form 4099.F, v2.0) — Fannie Mae (2019-08; accessed 2026-10-22)
- FAQs for modification of sections 25C, 25D, 25E, 30C, 30D, 45L, 45W, and 179D under Public Law 119-21 (FS-2025-05) — IRS (2025-08-21; accessed 2026-10-22)