If your gas or oil boiler is nearing the end of its life, someone has probably already suggested a heat pump — and you’ve probably heard six conflicting opinions about them. Here’s a plain-English rundown from a local installer: how an air source heat pump actually works, what the efficiency numbers mean, what grant money is genuinely on the table in 2026, and how it all fits together with solar panels.
How an air source heat pump works
An air source heat pump (ASHP) is best understood as a fridge running in reverse. A refrigerant in the outdoor unit absorbs heat from the air passing over it, a compressor squeezes that refrigerant to raise its temperature, and a heat exchanger transfers the warmth into the water feeding your radiators and hot water cylinder.
The crucial point is that it doesn’t create heat by burning anything — it moves heat that already exists in the outside air into your home. Even cold air holds usable heat energy: official government guidance confirms heat pumps draw warmth from the air even in sub-zero weather, so a typical Kent winter sits well within their working range.
Because the electricity only powers the transfer, rather than being converted directly into heat, a heat pump can deliver more heat energy than the electricity it uses. That’s where the efficiency figures come from.
SCOP: the efficiency number that matters
A boiler can never give you more heat than the energy in the fuel it burns. A heat pump can.
Its efficiency is expressed as a coefficient of performance (COP) — units of heat out for every unit of electricity in. Because performance changes with the outdoor temperature, the figure worth comparing is the SCOP (seasonal coefficient of performance), which averages efficiency across a whole heating season. A SCOP of 3 means each kilowatt-hour of electricity delivers roughly three kilowatt-hours of heat. Government guidance puts it simply: heat pumps are around three times more energy efficient than traditional boilers.
One honest caveat from the installer’s side: SCOP depends heavily on design. Lower flow temperatures, properly sized radiators and reasonable insulation all push efficiency up; a rushed, copy-and-paste installation drags it down. Every good heat pump starts with a room-by-room heat-loss survey, not a rule of thumb.
The Boiler Upgrade Scheme: £7,500 off — £9,000 for some homes
The Boiler Upgrade Scheme (BUS) is the government grant for replacing fossil fuel heating in England and Wales, administered by Ofgem. As of August 2026, the scheme provides:
- £7,500 towards an air source heat pump (the standard air-to-water type described above)
- £9,000 towards an air source or ground source heat pump for eligible off-gas-grid properties currently heated by oil or LPG — available from 21 July 2026 until 31 March 2027
- £2,500 towards an air-to-air heat pump in residential properties
That £9,000 rate matters locally. If your home is in one of the villages that was never connected to mains gas — and you’re filling an oil tank every winter — you’re exactly who this uplift was designed for.
Who’s eligible
Under the official eligibility rules, you must own the property (that includes second homes, rental properties and business premises) and be replacing a fossil fuel heating system — oil, gas, electric or LPG. Most new-build properties, social housing, and homes that have already received government heat pump funding are excluded. Once an application is made, the heat pump must be installed and commissioned within 120 days.
How the money actually reaches you
You never claim the grant yourself. The scheme is installer-led: an MCS-certified installer applies to Ofgem on your behalf, the grant value is taken off your quote as an upfront discount, and you simply confirm your consent when Ofgem contacts you. This is why MCS certification isn’t just a badge — without it, an installer can’t access the scheme at all. Athena Solar & Electrical Solutions is MCS certified and a member of the RECC and HIES consumer codes.
Don’t forget the VAT position
Until 31 March 2027, installing an air source heat pump in residential accommodation is zero-rated for VAT under HMRC’s energy-saving materials rules; from 1 April 2027 the rate reverts to 5%. Combined with the BUS grant, 2026 is an unusually well-supported moment to make the switch.
Pairing a heat pump with solar PV
A heat pump runs entirely on electricity — so every kilowatt-hour your roof generates is a kilowatt-hour you don’t have to buy to heat your home.
We’ll be honest about the seasonal mismatch: solar output peaks in summer, while heating demand peaks in winter. But the pairing still earns its keep. Hot water is a year-round load your panels can feed daily. A battery lets you shift daytime generation — or cheap overnight electricity — into the hours the heat pump works hardest. And government modelling suggests a heat pump run on a smart electricity tariff can cost around £100 a year less than a gas boiler, before any self-generated solar power is counted.
There’s a carbon case too: the same guidance puts a heat pump’s emissions at up to 70% less CO2 than a gas boiler over 15 years.
Is your home suitable?
Most Kent homes can run a heat pump well with the right design — including older properties, provided the system is sized honestly. The deciding factors are your home’s heat loss, whether the existing radiators can run at lower flow temperatures, space for the outdoor unit, and room for a hot water cylinder. Some homes need a few radiators upsized or insulation topped up first. A proper survey will tell you all of this before any money changes hands — and a good installer will tell you plainly if a heat pump isn’t the right answer for your house yet.
