How long it lasts
Average lifetimes from the Department of Energy's own analyses, the numbers it uses to set efficiency standards. Your unit's age is on its serial number.
| System | Average life (years) | Source |
|---|---|---|
| Gas tank water heater | 14.5 | DOE Consumer Water Heaters TSD (2024), App. 8G |
| Electric tank water heater | 15.1 | DOE Consumer Water Heaters TSD (2024), App. 8G |
| Heat pump water heater | 13 | ENERGY STAR heat pump water heater assumptions (13 years) |
| Gas tankless water heater | 20 | DOE Gas-fired Instantaneous Water Heaters TSD (2024), Table 8.3.5 |
| Gas furnace | 21.4 | DOE Consumer Furnaces TSD (2023), App. 8G |
| Central air conditioner | 18–24.9 | DOE Residential CAC & HP TSD (2016), Table 8.2.59 |
| Heat pump (ducted, outdoor unit + air handler) | 15.1–16.4 | DOE Residential CAC & HP TSD (2016), Table 8.2.59 |
| Gas boiler | 26.9 | DOE Consumer Boilers NOPR TSD (2023), Table 8.3.5 |
Central AC and heat pump lifetimes differ by climate; the range runs from hot-humid to milder regions.