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 heat pump is an air conditioner that can run backwards. The same compressor that cools the house in July heats it in January, so a heat pump in a four-season climate works roughly twice as many hours a year as a cooling-only system. That is the whole reason its typical life is a few years shorter than a furnace's.
The failure points are the same as an AC: compressor, reversing valve, fan motors, capacitors, and the indoor coil. Defrost controls and the reversing valve are the heat-pump-specific extras. Trane, Lennox, Bryant and InterNACHI all put the range at 10 to 15 years.
Newer cold-climate inverter heat pumps run at variable speed, which is easier on the compressor than the on-off cycling of older single-stage units. They have not been in homes long enough to show whether that stretches the lifespan.
Find the serial number and decode it: Rheem · Ruud · Goodman · Amana (heating and cooling) · Daikin · Carrier · Bryant · Payne · Day & Night · Heil / Tempstar / Comfortmaker / Arcoaire / KeepRite · Lennox · Armstrong Air / AirEase / Concord / Allied · Ducane · Aire-Flo · Trane · American Standard (heating and cooling) · York · Luxaire · Coleman / Evcon · Fraser-Johnston / Champion / Guardian · WeatherKing · Nordyne / Intertherm / Miller / Maytag / Frigidaire / Tappan / Westinghouse / Kelvinator / Gibson / Broan · Comfort-Aire / Heat Controller / Century · Bosch (heat pumps and geothermal)
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