Heat pumps at work

Everything you need to know about heat pumps

The spotlight has been placed firmly on heat pumps for homes in the UK, as a way to tackle the cost of living crisis, rising utility bills and concerns about climate change in one fell swoop.

With a nil rate of VAT introduced on heat pump prices for the next five years, as well as grants of up to £5,000 from the government to cover the cost of a heat pump boiler upgrade, the incentives are in place to make now the time to switch.

So how do heat pumps stack up in terms of energy cleanliness, cost and security – and are they really a silver bullet for household energy bills and carbon emissions?

What is a heat pump?

A heat pump system works by capturing heat from outside your property and bringing it inside where it can be used for central heating or to heat your hot water.

There are several types of heat pump including air source heat pumps and water source heat pumps, although the most commonly known are ground source heat pumps, which draw up thermal energy from deep below the ground.

Heat pump systems need a small amount of electricity to run. However, the heat they bring in is recovered from the environment and has no intrinsic carbon footprint, and heat pump running costs are generally very low.

How does a heat pump work?

In general, heat pumps work by compressing a refrigerant gas, which increases its pressure and temperature. As this heat is released into your property, the gas expands again, and the cycle begins once more.

This simple principle is at the heart of ground source heat pumps, air source heat pumps and water source heat pumps alike, as well as powering your heat pump water heater or your heat pump central heating.

A key difference depends on the source of the thermal energy brought into your premises, and we’ll look in more detail at this below when we list the different types of heat pump system.

Is a heat pump better for the environment?

While heat pumps are currently being discussed in terms of energy prices, they have been around for a long time as a supposedly eco-friendly alternative to conventional boilers.

As the Energy Saving Trust explains, heat pumps are very efficient. For every unit of electricity they use, they typically give out several units of thermal energy – a ratio called the heat pump system’s Coefficient of Performance, or CoP.

The best heat pump in theory is the one with the highest CoP. There are seasonal variations in the CoP, but heat pumps work all year round, even in the winter.

Because of this, the best heat pump central heating will usually be significantly better for the environment in terms of carbon emissions and fossil fuel consumption, making them a more sustainable long-term option for warmer homes and eco-friendly heat pump water heaters.

The boiler upgrade scheme

In April 2022, the government launched the Boiler Upgrade Scheme, offering grants of up to £5,000 for homeowners to install low-carbon heating systems including heat pump boilers.

To qualify, homeowners must have a newly installed eligible low-carbon heating system commissioned (i.e. completed and turned on for the first time) on or after April 1st 2022, with applications for grants and payments starting about seven weeks later on May 23rd.

Under the scheme, homeowners can qualify for:

    • £5,000 to install a biomass boiler in a rural property with no mains gas connection
    • £5,000 to install an air source heat pump in any property
    • £6,000 to install a ground source heat pump in any property

Eligibility is open to people:

    • who own a property in England or Wales
    • with an installation capacity of up to 45kWth (most domestic properties)
    • and an Energy Performance Certificate to show the property meets recommended standards of loft and cavity wall insulation.

There are some exceptions. Some properties are exempt from the insulation requirement, for example, and new-build properties (other than self-build projects) normally will not qualify.

If you are building your own home or plan to install a heat pump system as part of refurbishment work, we have a range of skip sizes available to hire, giving you a safe, secure and eco-friendly way to get rid of any materials you no longer need.

The different types of heat pump system

There are several main types of heat pump systems. Here are the three most common kinds of heat pumps overall:

Air source heat pump

Air source heat pumps move thermal energy from the open air outside into your property by blowing the air over a heat exchanger.

Because they can extract small amounts of thermal energy from very large volumes of air, they can work even in cold weather.

Ground source heat pump

Ground source heat pumps use underground pipes to bring thermal energy up from deep below the ground.

Because underground heat levels are less affected by changes in weather conditions, this is a good option for reliability and consistent output.

Water source heat pump

Large bodies of water store heat well – that’s why the UK is warmed by North Atlantic sea currents in the winter months, and it’s the same principle that powers water source heat pumps.

If your property is close to a lake, aquifer or even flooded mineshafts, a water source heat pump can extract thermal energy from it in winter, and can even transfer heat into the water in summer to act as a kind of air conditioning system for your home.

How much does a heat pump cost?

Heat pump prices vary depending on the type of heat pump you install, and of course you can expect to pay more for the best heat pumps on the market.

As a rule of thumb, the upfront heat pump cost before any government incentives are applied can be in the region of:

    • £20,000 – £40,000 for ground source heat pumps
    • £20,000 – £30,000 for water source heat pumps
    • £8,000 – £18,000 for air source heat pumps

Heat pump installation costs are lower for air source heat pumps because the process is less complicated, compared with installing the underground pipework needed for ground source and water source systems.

There is a heat pump operating cost to consider, as all heat pumps need an electricity supply to operate. Running costs can be a little higher than the cheapest tariffs for electricity, gas and heating oil BUT when wholesale energy prices rise, heat pumps really come into their own.

Overall, if you want to be protected against the highest part of the wholesale energy price cycle and you want more consistent domestic energy costs, heat pumps are a good option.

Where can I buy a heat pump?

It’s a great time to buy a heat pump, with the incentives available to cover your heat pump installation costs and the reduced rate of VAT in the coming five years.

To qualify for the Boiler Upgrade Scheme, search for an MCS certified installer. You can contact multiple installers in your area and compare quotes to get the best heat pump installation prices from an accredited installer.

What does MCS stand for in heat pumps?

MCS is a government-supported, nationally recognised quality assurance scheme. It stands for Microgeneration Certification Scheme and covers small renewable energy systems like domestic heat pump installations.

If you’re applying for the Boiler Upgrade Scheme, it’s the best place to start looking. An accredited installer should know if you’re eligible for the grant and can handle the application – you’ll just need to confirm they are acting on your behalf when contacted by the energy regulator Ofgem.