How Much Does It Cost To Replace A Boiler With A Heat Pump?

Cost To Replace a Gas Boiler With a Heat Pump 

The cost of replacing a gas boiler with a heat pump varies from property to property. An average UK property will need an air source heat pump in the 5kW-10kW range. Replacing a gas boiler with a unit like this could cost anywhere from £10,000-£15,000.

However, most households will qualify for a £7,500 government grant (the Boiler Upgrade Scheme). Essentially, the cost to upgrade your old gas boiler with a modern and efficient heat pump, could be as low as £2,500 after this funding. 

As an example, we can replace your gas boiler with a Vaillant aroTHERM 5kW unit for well under £3,000. This assumes you utilise your existing hot water cylinder. 

Below, we'll explain in detail what can affect the exact cost of upgrading your boiler to a heat pump.

You can also see heat pump replacement costs using our clickable form here. 

Government Grants

The biggest thing that affects the cost of a heat pump replacement, is whether or not your household qualifies for a government grant. Of all the grants available, the Boiler Upgrade Scheme is the most commonly used. This is specifically designed for households replacing their boiler with a heat pump to make their property more energy efficient. 

Originally, the Boiler Upgrade Scheme offered consumers up to £5,000 in funding. The revised grant scheme offers up to £7,500 per household. 

Most UK households are eligible, but you can confirm this by checking out our grant eligibility page here. 

So, what does the installation cost for a heat pump look like when replacing a gas boiler after the £7,500 government grant? For a 5kW high quality system like the Vaillant aroTHERM, we fit these for under £3,000. 

This is the price when utilising your current hot water cylinder. If you have a gas combi boiler (which doesn’t utilise one) a cylinder will need to be installed, bumping the cost to just over £4,000.

You can also investigate other ways to get funding and reduce costs for a heat pump replacement over at our heat pump grants page. 

These include the likes of: 

• Warmer Home Scotland: Up to £10,000 in funding
• Nest, Wales: Perfect for those receiving a means tested benefit
• ECO4: Grants available for households in England and Wales for eco-friendly upgrades, including air source heat pumps

Heat Pump Brand, Size & Efficiency

The exact heat pump (brand, size and efficiency) is going to have a huge bearing on the overall cost of replacing your gas boiler. You’ll want a heat pump from a leading brand. As you can see over at our heat pump reviews page, stick to the likes of: Ideal Heating, Vaillant, Daikin, Samsung and Grant. 

Choosing one of these brands could increase cost by £500 over a no-name brand. However, what you’ll get is a high quality unit with a long warranty (7-10 years in general). Heat pumps are expensive to replace, so a long warranty is incredibly important.

Alongside this, top brands such as these have a much higher SCOP (Seasonal Coefficient of Performance). Many leading manufacturers offer pumps that are 400% efficient, helping you to save huge amounts on your energy bills.

And of course, remember that the bigger the heat pump you need, the more it’s going to cost. There’s likely to be a £1,500-£2,000 difference in cost between a 5kW and 10kW heat pump replacement. 

Looking for specific recommendations? The most popular units we install include the likes of the:

• Ideal Logic Air
• Vaillant aroTHERM Plus
• Daikin Altherma
• Grant Aerona³ R32

And if you’re looking for larger units, we’ve got guides covering 8kW and 16kW heat pumps here.

Radiator Size & Efficiency

The majority of the efficiency gain with heat pumps comes from correctly sizing radiators. Essentially, heat pumps work at much lower temperatures than gas boilers. 

Whilst the average gas boiler will operate at a flow temperature in the region of 60°C to 70°C, a heat pump will operate at a flow temperature of approximately 35°C to 55°C. This puts a lot less strain on the heat pump, improving efficiency. In order for it to work efficiently at these lower temperatures, heat pumps rely on larger radiators. 

As part of our install, we’ll upgrade one of your radiators to a larger one for free. However, in order to maximise the efficiency of your heat pump, you may need to upgrade more radiators in your property.

The expected additional cost? Depending on the size and complexity of the install, each radiator upgrade could cost £250-£350. Of course, if your system already uses large and efficient radiators with your gas boiler, you might not need any radiator upgrades.

We’ve got a full guide to radiators and heat pumps here. 

Reusing An Old Cylinder

Unlike a combi gas boiler (that heats water on demand), a heat pump heats it over time, storing it in a hot water cylinder. If your central heating system uses a gas combi boiler, it won’t have a cylinder; you’ll need one installed as part of replacing your boiler with a heat pump. 

The exact cost of cylinder installation varies depending on size, brand and installation complexity. 

As a guideline, expect the price difference between using your current hot water cylinder (if you have one) and having one installed, to be in the region of £1,500.

What's Included

Heat pump replacement that involves switching from a gas boiler is much more complicated than simply swapping to a new boiler. 

A typical installation will include the likes of: 

Our base price for heat pump installations doesn't include a hot water cylinder. This is simply due to the fact that some heating systems use a cylinder that we can then re-use. 

The base price for a heat pump replacement (reusing an existing cylinder) starts at £2,699 for a 5kW unit. Expect this cost to rise to around £4,400 (after the government's £7,500 grant) if we need to fit a new cylinder. 

To get prices on upgrading your boiler to a heat pump, use our clickable heat pump quote form here. 

Is Replacing a Gas Boiler With a Heat Pump Worth it?

Deciding whether replacing a gas boiler with a heat pump is worth it depends on a few things including: energy prices, installation costs and the overall efficiency of your property. 

Heat pumps typically have a higher upfront installation cost, but their efficiency rating is also much higher and environmental impact is much lower. 

Benefits: 

• 300-400% efficient, compared to gas boilers that are up to 94% efficient
• Cuts carbon emissions in the average property by approximately 60%
• Cheaper to run for those on competitive electricity tariffs
• Can be coupled with solar panels to reduce energy bills

Drawbacks: 

• Higher upfront cost to install
• High running costs for old and inefficient homes
• System upgrades may be required (larger radiators for instance)

So, what type of property would benefit from upgrading from a gas boiler to a heat pump?

Households that have the following will benefit: 

• New builds
• High quality insulation, including new windows and doors
• Properties using an old and inefficient boiler
• Households that qualify for the £7,500 Boiler Upgrade Scheme grant

If you live in an old property that's poorly insulated (such as a country cottage), it's unlikely you'll see the full benefit of installing a heat pump.

For everyone else, you can get a free quote here. There you’ll be able to spec a heat pump replacement specifically for your property, upgrading your gas combi, system or regular boiler in the process.

FAQ

Who qualifies for the Boiler Upgrade Scheme grant? 

Via the Boiler Upgrade Scheme, if you own your home (it can be a Buy-to-let) and haven't received this grant before, you could get up to £7,500 in funding. 

How much does a heat pump replacement cost? 

After accounting for the government's £7,500 grant, prices start at around £2,600 for a small 5kW air source heat pump that's replacing a gas boiler.

Can a heat pump be cheaper to run than a gas boiler?

Typically, heat pumps cost slightly more to run than a gas boiler. However, heat pumps can be cheaper to run if: 

• Your home is well insulated
• The heat pump has a high SCOP (4 or higher)
• Your electricity tariff is highly competitive
• The boiler your replacing isn't A-rated

Why is heat pump installation more expensive than gas boiler replacement?

Upgrading a boiler to a heat pump is a complicated job which involves: system redesign, heat loss survey, radiator upgrades and on many occasions, a hot water cylinder installation. 

However, with the rising cost of boiler installation (£2,000-£3,000), heat pumps are becoming more and more cost effective. 

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

Yes. For households that have high quality insulation, an inefficient boiler and have access to the £7,500 Boiler Upgrade Scheme, a heat pump replacement is worth it. 

And that’s it for our heat pump replacement cost guide. 

Ready to get prices on-screen? Use our clickable heat pump quote form here.