Your boiler's on its last legs. Or you're fed up watching your heating bills climb every winter. Or you just want to stop burning fossil fuels in your home but don't know what replaces a gas boiler.

Heat pumps are the answer for most homes. They're 3-4 times more efficient than boilers, they work with your existing radiators in most cases, and the government grant covers most or all of the cost for many installations. Your heating bills drop, your home's more comfortable, and you've cut your fossil fuel use substantially.

But they're not right for every situation. Here's what you need to know.

The Main Options

Air source heat pump (ASHP) - air to water: This is what we recommend for most homes. Takes thermal energy from outside air and uses it to heat water for your radiators and taps. Works reliably down to -15°C and captures 3-4 kWh of heat for every 1 kWh of electricity used.

Works with your existing radiators in most homes. Government grant covers £7,500. Your cost: typically £0-£10,000 after the grant.

Ground source heat pump (GSHP): Same principle but extracts thermal energy from the ground via buried pipes. Slightly more efficient (3.5-4.5 times) but costs about £10,000 more to install. Only makes sense if you have the land and budget.

Air to air heat pump: You've probably come across this - we usually call it air-con. Heats and cools air directly. Good for homes without radiators or where overheating is a concern. No government grant yet. Can't provide hot water, so you need a separate solution for that.

Efficient gas boiler: Sometimes this is still the sensible choice - we'll be honest about when that applies.

We don't often recommend biomass boilers, infrared panels, electric boilers, or storage heaters - they don't make economic sense for most homes.

Who Should Get a Heat Pump

Heat pumps work brilliantly if:

You have or want solar to lower your bills - this is where heat pumps really shine. Heating with your own power during the day (and at night with a battery) makes the economics excellent

You're fed up with fossil fuels - heat pumps cut your home's fossil fuel use substantially

You want better comfort - consistent warmth throughout your home, fewer cold spots

Your home has reasonable insulation - at least loft insulation and cavity walls filled. Doesn't need to be perfect, but can't be terrible

You have space for the outdoor unit - about the size of a large suitcase, goes on an external wall or in the garden

You're doing other work anyway - renovating, extending, or improving insulation makes it an ideal time

Most homes with decent insulation are good candidates. Straightforward installations with existing radiators typically cost £0-£5,000 after the government grant.

How They're Different From Boilers

Boilers blast hot water through your system at 60-70°C for short periods. Heat pumps run at lower temperatures (35-50°C) for longer - low and slow, providing consistent gentle warmth throughout the day.

Most people find their homes more comfortable with a heat pump. No more waiting for the heating to kick in, fewer cold spots, just even warmth.

They work efficiently even when it's freezing outside - there's plentiful thermal energy in the air down to around -15°C that heat pumps can capture.

Will They Work With Your Existing Radiators?

Usually yes. Most existing radiators work fine with heat pumps - the system just runs at lower temperature for longer.

You might need to upgrade a few radiators to larger sizes if the existing radiators are small relative to the room they're in. A heat loss assessment (which happens before installation) identifies which rooms need this.

If you're doing major renovation work, underfloor heating is ideal for heat pumps - large surface area, low temperatures, perfect match.

What It Costs

Air source heat pump (most common):

• System cost: £7,500-£17,500 installed

• Government grant: -£7,500

• Your cost: £0-£10,000

Straightforward installations with existing radiators fall towards the lower end. If you need new radiators, a hot water cylinder, or complex pipework, it can cost more.

Ground source heat pump:

• System cost: £18,000-£30,000

• Government grant: -£7,500

• Your cost: £10,500-£22,500

Only worth it if you have the land and value the extra efficiency.

Efficient gas boiler (for comparison):

• £2,000-£4,500 installed

• No grant

What You'll Save

If you have solar: Significant savings. You're heating with your own power during the day. Add a battery and you're doing it at night too. This is where heat pumps make brilliant financial sense.

Replacing oil heating: £400-£800/year typically. Oil is expensive and prices swing wildly.

Replacing electric storage heaters: £600-£1,000/year typically. Storage heaters cost a fortune to run.

Replacing an old gas boiler (no solar): £100-£300/year typically. The bigger benefits are comfort (consistent warmth, no cold spots) and cutting fossil fuel use. If you're replacing a modern efficient boiler and don't have solar, the financial case is about future-proofing and comfort rather than dramatic savings.

Running costs at current prices: heat pumps cost slightly less than gas in a well-insulated home. With solar, costs drop dramatically.

The Insulation Factor

Heat pumps work best in well-insulated homes. That doesn't mean perfect - it means at least loft insulation topped up and cavity walls filled (or solid wall insulation if your walls are solid).

If you're planning insulation anyway: Do that first. You'll need a smaller, cheaper heat pump afterwards.

If insulation is too expensive: You can still get a heat pump - it just needs to be larger. The grant still applies and you're still cutting fossil fuel use.

This isn't all-or-nothing. A heat pump in a reasonably insulated home is still better than an old boiler.

When a Gas Boiler Makes More Sense

Sometimes a heat pump isn't right:

Your home has very poor insulation and you can't afford to improve it - a heat pump would need to be oversized and expensive, even with the grant. An efficient gas boiler might be the pragmatic choice until you can insulate.

You're planning major renovation in 2-3 years - better to do insulation and heating together than twice.

Listed building or conservation area restrictions - external units may not be permitted.

A modern condensing gas boiler is 20-30% more efficient than some old ones. It's not the future, but it might be the sensible solution for your situation.

The Government Grant

£7,500 towards an air source or ground source heat pump. The grant goes directly to the installer, reducing your bill.

You qualify if:

• You're replacing a fossil fuel heating system (gas, oil, LPG)

• You have an EPC for your property (we can arrange this)

• The installer is MCS-certified (all ours are)

This grant makes heat pumps genuinely affordable for most homes.

Air to Water vs Air to Air

Most homes suit air to water - heats water for radiators, provides hot water, eligible for the £7,500 grant, works with existing infrastructure.

Air to air (essentially air-con) suits specific situations:

• Homes without radiators

• Modern homes that overheat in summer

• Want cooling as well as heating

• Can't provide hot water (need separate solution)

• No government grant yet

The Installation

Takes 2-3 days typically. External unit installed, pipework connected, hot water cylinder added if needed (combi boilers don't have them, heat pumps do), controls fitted, system commissioned.

Main disruption is installers in the house for a few days and some pipework changes. Nothing like a full renovation.

Once it's in, it's largely fit-and-forget. Heat pumps need minimal maintenance.

What to Know Before Deciding

What are you replacing? Old gas boiler, oil, electric? This massively affects your savings.

Do you have or want solar? Changes the economics completely - heating with your own power rather than expensive grid electricity.

What's your insulation like? Reasonable insulation means a smaller, cheaper, more efficient system.

What matters most to you? Bills? Comfort? Cutting fossil fuels? Future-proofing? This affects whether a heat pump is right now or later.

How We Approach Heating

We recommend air source heat pumps for most homes - they're the most cost-effective way to cut heating costs and fossil fuel use whilst improving comfort.

Sometimes ground source makes sense if you have land and budget. Sometimes air to air works for specific situations. And sometimes an efficient gas boiler is the pragmatic choice if a heat pump doesn't fit right now.

Planning your heating as part of wider improvements? We help you work out what heating system makes sense for your home, how it fits with insulation and solar, and whether to do everything now or phase the work over time. See how Furbnow works.