Heating, ventilation, and air conditioning systems require proper and regular maintenance in
order to work efficiently, but even in the best case scenarios most components of such systems only
last 15 to 25 years. Furnaces on average last 15-20 years, heat pumps 16 years, and air conditioning
units 10-15 years. Tankless water heaters last more than 20 years, while an electric or gas water
heater has a life expectancy of about 10 years. Thermostats usually are replaced before the end of
their 35-year lifespan due to technological improvements.