UK's cheapest heat pumps go on sale but would you ditch your boiler?

Octopus Energy has unveiled an air-source heat pump that can be installed for as little as £2,500 and aims to tackle the major objection to such devices: price.

The announcement puts the company in competition with British Gas, which recently said it would cut heat pump costs to £2,999 per customer.

Heat pumps recover heat from the air or the ground and can replace traditional gas boilers.

The government wants to install 600,000 heat pumps a year by 2028 to reduce carbon emissions in the UK. But the country currently only has about 42,000 heat pumps per year, according to the European Heat Pump Association.

The main obstacle preventing more homes from choosing a heat pump is the the cost of their purchase and assembly. Devices cost between £8,000 and £30,000 to buy and install, with the wide price range reflecting the type you buy and the type of home you have.

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Cost savings: heat pumps can reduce your heating bills by up to 25%, but can incur hidden costs

But Octopus says its heat pumps could cost as little as £2,500 per household and no more than £4,000 for most homes.

This is based on the homeowner receiving a voucher of up to £6,000 under the government’s Boiler Upgrade Scheme and then topping it up with £2,500 to £4,000.

The Octopus heat pumps will be installed later this year, but the company did not specify when exactly. The company hopes to shave £500 off an overall heat pump bill this year.

What are the advantages of a heat pump?

Experts say they can cut your energy bills by up to 25% because the appliances require less energy to operate, which also makes them greener than boilers. They can also last longer than boilers – up to 20 years.

Are there any hidden costs with heat pumps?

Getting the most out of a heat pump can involve additional costs to get the most out of it.

Poorly insulated properties will not see the same benefits from a heat pump, as the appliances operate at lower temperatures than boilers.

This means that homeowners installing a heat pump should consider choosing decent wall and attic insulation, as well as double glazing.

The cost of this can run into the thousands of pounds – but will help lower energy bills from then on.

> What you need to know about professional home insulation

You may also need larger radiators to get the most heat from a heat pump.

This is because appliances do not heat water as hot as boilers, so radiators with larger surface areas may be needed to maximize heat.

Your home must also be suitable for the installation of a heat pump.

A geothermal heat pump requires space outside to bury the pipes needed to produce heat.

Geothermal and air-source heat pumps require the installation of a hot water tank, which may not be suitable for small apartments.

Fully grounded: the most expensive heat pumps draw heat from the ground itself

How do heat pumps work?

There are two main types of heat pumps: air source and ground source.

An air-source heat pump is like an air conditioning unit that sits outside the house. They are equipped with a fan that brings in air from outside the house.

This moves over a heat exchange surface, the heat causing the evaporation of a special refrigerant liquid which turns into gas. This is compressed, increasing the pressure, increasing the temperature and is then used to produce hot water.

Hot water should be stored in a water tank inside the house, where it can supply radiators, taps and showers.

The system runs on electricity and the two units are connected by copper piping.

Geothermal heat pumps are more expensive and use pipes buried in the garden to extract heat from the ground.

This heat can then be used to heat radiators, underfloor or warm air heating systems and hot water in your home.