Set your boiler's age and fuel below to see how the next ten years of carbon stack up: gas versus heat pump.
9 yr
brand new10 yr20 yr
get-ready zone
Breakdown odds are climbing. Get your ducks in a row.
Roughly a 10% chance of a sudden breakdown this year. The odds keep climbing every year you wait.
Next 10 years of carbon
For a typical UK home (7,790 kWh/yr of heat).
Stick with gas17.3 t
Switch to a heat pump2.9 t
embodied (1,200 kg)operational, falls as grid cleans up
Saved by switching14.4 t
Today's gas emits 1.73 t/yr. A heat pump emits 0.36 t/yr now, falling toward 0.06 t/yr by 2035 as the grid cleans up.
My gas bills are…
Lock-in lottery if your boiler dies before you're ready
A panic-swap to gas locks in another 12+ years of fossil heat. Versus a planned heat-pump path, that costs roughly 18 extra tonnes of CO₂.
The chance of a breakdown rises with age: on our assumed curve, about 11% a year at age 10 and 19% at 15. If it fails first, a rushed swap means a decade locked in to gas.