Should I Replace My Gas Boiler with a Heat Pump?

If your gas boiler is over 10 years old, the answer is almost certainly yes — especially with the £7,500 BUS grant reducing the net cost to as little as £4,000. Running costs match gas today and will beat it as electricity prices are rebalanced. A heat pump also future-proofs your home against the 2035 gas boiler phase-out.

This is one of the most common questions we hear from UK homeowners. The answer depends on your boiler's age, your home's insulation, your budget, and your long-term plans. This guide walks you through the key questions honestly, building on our heat pump vs gas boiler pillar guide.

The Quick Answer

For most UK homeowners, replacing a gas boiler with a heat pump will save money over the system's lifetime, reduce your carbon footprint, and future-proof against the 2035 gas boiler phase-out. With the £7,500 BUS grant, the economics are increasingly compelling. But "most" is not "all."

When You Should Definitely Switch

• Your boiler is 12-15 years old or failing: You would spend £2,500-£4,000 on a new gas boiler anyway — redirect that towards a heat pump
• You are planning renovations: Adding a heat pump during building work reduces disruption and cost
• Your home is reasonably insulated: Loft insulation, cavity walls, double glazing — you do not need perfection
• You want to future-proof: A heat pump lasts 20-25 years, well beyond the 2035 deadline

When It Makes Sense to Wait

• Your boiler is under 5 years old and working well: The financial case is weaker since you have years of use remaining
• You are planning to move soon: Unless a heat pump adds value to the sale price (it often does for eco-conscious buyers)
• Major insulation work is needed first: Address the worst heat loss before installing a heat pump

When a Heat Pump Might Not Suit

• Very small flat with no outdoor space: Some properties genuinely cannot accommodate the outdoor unit
• No space for a hot water cylinder: If you have a combi boiler and absolutely no room for a cylinder

These situations are rare. Most homes can accommodate a heat pump with creative solutions. Use our suitability checker to assess your property.

The Cost Comparison

25-year comparison includes two gas boilers vs one heat pump. Running costs at 2026 prices with 3% annual inflation.

Over 25 years, the heat pump typically costs less because you need two gas boilers versus one heat pump. With solar panels powering the heat pump, the savings are even greater.

Practical Considerations

Radiators: Many existing radiators work fine with a heat pump. Your installer will assess this during the survey. See our radiator guide for detail.

Hot water cylinder: If you have a combi boiler, you will need to add a cylinder. If you already have a system boiler with a cylinder, conversion is simpler.

Disruption: A typical installation takes 3-5 days. See our installation guide for what to expect.

Frequently Asked Questions

Is it worth replacing a working gas boiler with a heat pump?

If your boiler is over 10 years old, getting quotes now makes sense so you are prepared. The strongest case is when your boiler needs replacing anyway, as the additional cost is modest after the £7,500 grant.

How much does it cost to switch from gas to a heat pump?

After the £7,500 BUS grant, a typical installation costs £4,000 to £8,500. Compared to a new gas boiler at £2,500-£4,000, the extra outlay is modest — and running costs are comparable or lower.

Will I save money with a heat pump versus gas?

Running costs are roughly equal at standard tariff rates. With a heat pump tariff or solar panels, the heat pump is clearly cheaper. Over the 20-25 year lifespan, total costs favour the heat pump.

Do I need to change my radiators?

Not always. Many existing radiators work at lower heat pump temperatures. Your installer assesses during the survey and recommends upgrades only where needed.

What about the gas boiler ban in 2035?

From 2035, no new gas boilers will be installed. Switching now means your heat pump lasts well beyond that date. Waiting risks missing grant funding and facing a rush of demand.

Can I keep my gas boiler as backup?

Yes — hybrid systems use both. However, most well-installed heat pumps do not need a backup. A standalone heat pump is simpler and qualifies for the full BUS grant.