Hybrid Heat Pumps: The Best of Both Worlds?

Not ready to ditch the gas boiler entirely? A hybrid heat pump might be the pragmatic middle ground. It pairs a smaller air source heat pump with your existing boiler, using each when it's most efficient.

How hybrid systems work

The concept is simple: the heat pump handles heating for most of the year (roughly 8-9 months), and the gas boiler kicks in during the coldest periods when the heat pump would need to work hardest and least efficiently.

A smart controller switches between the two based on outdoor temperature and energy costs. Typically:

• Above 3-5C: Heat pump provides all heating
• Below 3-5C: Boiler takes over or assists


• Hot water: Usually the boiler (faster recovery)

The crossover temperature is adjustable. If you're on a cheap heat pump tariff, you might set it lower so the heat pump runs more often.

What does it cost?

A hybrid system is cheaper than a full heat pump installation because the heat pump is smaller and you don't need to modify your existing heating system:

• Hybrid heat pump installation: £5,000 - £8,000
• Full ASHP installation: £10,000 - £15,000


• After BUS grant (hybrid eligible): Can be as low as £500 - £3,000

Yes, hybrid systems qualify for the £7,500 BUS grant, which makes them remarkably affordable.

The running cost picture

A well-configured hybrid typically:

• Reduces gas consumption by 60-70%
• Increases electricity consumption by roughly the amount the gas drops


• Results in overall heating cost reduction of 20-35% versus gas-only

The exact savings depend heavily on your tariff. On a standard dual-fuel tariff, savings are modest (gas is cheap per kWh). On a heat pump tariff with cheap off-peak electricity, savings are substantial.

Who should consider a hybrid?

Hybrid systems make particular sense if:

• Your home is hard to insulate (solid walls, listed building). A full heat pump needs the home to be reasonably well insulated. A hybrid can fall back to the boiler when needed.
• You can't fit a large enough heat pump. Limited outdoor space? A smaller hybrid unit needs less room.


• Your boiler is relatively new. If you replaced your boiler 3-5 years ago, scrapping it feels wasteful. A hybrid extends its useful life.


• You want to reduce emissions without a full commitment. 60-70% gas reduction is significant, and you can convert to full heat pump later when the boiler eventually dies.

The limitations

• You're still connected to gas, so you still pay a gas standing charge (about £113/year)
• Carbon savings are good but not as good as a full heat pump


• The boiler will still need annual servicing


• Some complexity in having two systems

Our view

Hybrids are an underrated option. They deliver most of the carbon benefit of a full heat pump at significantly lower cost and disruption. For older or harder-to-treat homes, they're often the most sensible first step.

We compared air source vs ground source heat pumps in a previous piece - hybrids sit alongside ASHPs as a third option worth considering. Get quotes that include hybrid options and compare the numbers for your specific home.