A standard tank water heater usually lasts 8 to 12 years. Some make it to 15 with soft water and a replaced anode rod; some fail at 7.
A gas tankless water heater usually lasts 15 to 20 years, and sometimes longer, because there is no tank to rust through. Scale buildup in the heat exchanger is what shortens its life.
A heat pump (hybrid) water heater is expected to last 10 to 15 years. ENERGY STAR bases its savings math on 13 years.
A gas furnace usually lasts 15 to 20 years. Well-maintained units in mild climates reach 25; units that run hard with dirty filters fail sooner.
A central AC condenser usually lasts 12 to 15 years. In hot climates where it runs most of the year, 10 is more typical; in the north, 20 is possible.
An air-source heat pump usually lasts 10 to 15 years. It runs in both seasons, so it logs more hours than a furnace or an AC alone.
A ductless mini-split is a heat pump, so plan on 10 to 15 years, with 20 possible for a lightly used unit that is cleaned regularly.
The indoor unit of a geothermal system is expected to last 20 to 25 years. The buried ground loop is expected to last 50 years or more.
The age you just looked up is the kind of fact that gets lost. A written record of serial numbers, install dates, repairs and who did the work saves the next owner, inspector or insurer from guessing.
A lifetime logbook for the house, organized by system, with room for serial numbers, install dates, repairs and contractors. It stays with the house for the next owner.
Galvanized, polybutylene, cast iron and the sewer line: what fails, what it costs, what insurance won't cover and how to decide.
A buyer's guide to older homes: wiring, pipes, lead, asbestos, insurance refusals and what the repairs actually cost.
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