How long does a boiler or heat pump last

The decision turns on three things: how long the part was built to last, how hard yours has been used, and whether it has started warning you. The built-to-last number is the easiest to find and the least useful on its own, so start there and then adjust for the other two.

What each part of your heating system lasts

The boiler is almost always the first thing to go. The pipes, radiators, and underfloor loops around it outlast it two to three times over, which is why a failing heating system rarely needs replacing whole.

Part of the system	Typical lifespan	What usually ends it
Gas combi boiler	15–20 years	heat exchanger, pump, or control-board failure
Air-to-water heat pump	15–20 years	compressor failure, refrigerant leak, defrost-cycle degradation
Air-to-air heat pump	around 15 years	compressor failure, refrigerant leak, defrost-cycle degradation
Exhaust-air heat pump	around 15 years	compressor failure, refrigerant leak, extract-fan failure
Ground-source heat pump	15–25 years	compressor failure, ground-loop degradation, circulator pump
Steel panel radiators	20–35 years	internal corrosion, valve failure, sludge buildup
Wet underfloor heating	40–60 years	manifold failure, pipe leak, actuator failure
District heating substation	20–30 years	heat-exchanger fouling, valve failure, sensor drift

These ranges come from the RVB/BOEI durability handbooks, national and international energy-agency figures (the IEA and Finland’s Motiva), and the manufacturer and installer field data the planning model is built on. The gas-boiler figure is well established; the heat-pump figures are softer, because the inverter-driven market is still maturing and field data on the newest units is thin, especially for air-to-air.

For a ground-source system, the lifespan is the pump unit, not the hole in the ground. The borehole and its buried loop outlast the pump by decades, so when the pump reaches the end of its life you replace the unit and reuse the existing borehole. That is why the second ground-source pump costs far less than the first: the expensive drilling is a one-time cost, and the pump is the only part on a replacement cycle.

Age is not the same as remaining life

A 12-year-old boiler serviced every year can have more life left than an 8-year-old one nobody has touched. Components do not wear out on a straight line; they age on a two-inflection curve. They hold steady to about half their rated life, decline faster through the next quarter, then drop off a cliff past 75 percent. Annual servicing flattens the early part of that curve and pushes the cliff back; skipped servicing pulls it forward. Age is a weak predictor on its own. The real measure is wear: how hard the unit has worked and how well it has been kept.

The signs your unit is past 75 percent

Once a boiler needs its second non-routine repair in two years, you are paying for a replacement in instalments. The failure modes announce themselves before the unit dies. A boiler short-cycles or keeps losing pressure. A heat pump runs longer for less warmth or ices up in mild weather. Radiators develop cold spots where sludge has settled. Rising service frequency is the single most reliable signal; a part coming back on backorder is the quiet one, because it means the manufacturer is winding the model down and spares are about to get scarce.

When to start planning the replacement

Start planning once a heat pump passes three-quarters of its expected life, and at year 12 for a boiler, not the week it fails in January. For a short-lived air-to-air unit that three-quarter mark comes around year 11; for air-to-water or ground-source it is later. A heating system that dies in the cold gives you no time to compare quotes, so you take the first emergency rate offered.

Jussi’s air-to-air heat pump in Tampere is 14 years old, the most common type in Finnish homes. Air-to-air units run around 15 years, and in year-round Nordic heating duty often less, so at 14 Jussi is at the end of the curve rather than the three-quarter mark. The question is not whether it needs replacing but when. He gets quotes now, in summer, when installers compete for the work, rather than taking the first emergency rate when it fails in January.

What this means before you call anyone

The cheapest heating replacement is the one you saw coming. Knowing where your boiler sits on its curve turns a January emergency into a summer decision with three comparable quotes and a price you set in advance. That is the difference between paying an emergency rate and setting one.

appkeep tracks where each component in your house sits on its lifespan curve and flags the replacement before it becomes an emergency, and the mandate calculator caps what an installer can charge before you sign. When you are ready to price it, the boiler replacement cost guide has the current installed ranges for gas boilers and the cost structure for Nordic heat pumps. How much of the labour you claim back depends on where you live: Sweden’s ROT-avdrag and Finland’s kotitalousvähennys each take a share off the labour line before you pay.