What are heat pumps? How the gas boiler alternatives work, what they cost and how help fight climate change

Next month the government is set to release a new strategy likely to set a deadline for the UK gas boiler’s demise.

This means that over 80 percent of UK households will have to switch to a new heating system in the next 15-20 years. For most, the move will be from a gas boiler to a heat pump.

What is a heat pump?

A heat pump works by taking heat from a renewable source – either heat from the earth or the air – and transferring it into a liquid, compressing it to further increase the temperature. Then the heat is transferred from the liquid to water and pumped around your home to keep the rooms at a stable, comfortable temperature.

There are two main types of heat pumps.

A geothermal heat pump uses a network of underground pipes to extract heat from the subsurface into a liquid. That is then pumped into a heat exchanger where a bit of complicated chemistry will help raise the temperature. The heat is then converted back into water and the hot water is then pumped around your house by radiators or underfloor heating.

An air heat pump follows essentially the same process, but instead of extracting heat from the soil, heat is extracted from the air. It doesn’t have to be a warm day outside to work – heat pumps can even draw heat from the air at temperatures as low as -15 ° C.

What is the climate benefit?

Households are responsible for around 15 percent of the UK’s greenhouse gas emissions, with most of the pollution being caused by the gas millions of us use for heating and cooking. Climate experts agree that it is important that we switch to a carbon-free heating source as soon as possible in order to meet our climate goals.

Air and geothermal heat pumps both run on electricity and not fossil fuels. If this electricity is generated using wind turbines, solar panels, or other renewable technologies, then they are an environmentally friendly way to heat (and cool) your home.

How much do they cost?

The bad news is that heat pumps are currently significantly more expensive than a gas boiler. An air source heat pump will start at around £ 6,000 while a ground source heat pump will cost from £ 10,000.

Geothermal heat pumps require a decent piece of land to install the plumbing, so most homes will switch to an air source heat pump when switching.

The good news is that industry experts believe the price will drop rapidly in the years to come as the industry grows. Octopus Energy, which invests heavily in heat pumps, believes it can bring the average price down to £ 5,500 in the next 18 months.

Once installed, the operating costs are comparable to those of a gas boiler.

How easy are they to install?

Heat pumps work well if your home is already well insulated. If you install one in a large, draughty house, it has to use a lot of electricity to keep it cozy, making it inefficient and expensive to run.

Underfloor heating and larger radiators may also be required – the larger surface area helps to dissipate the heat better.

Once your house is ready for the heat pump, it takes just a few days for a technician to install the device. Once started, heat pumps work best by keeping the house at a constant temperature so it will likely run longer than a gas boiler, but at a lower temperature.

Do I have to get one?

It is possible. The only other way to decarbonise heating is to switch from gas boilers to hydrogen. This could be a solution for some households, but climate experts warn that in the future the UK will need its hydrogen supply to refuel ships, trucks and industrial sites so that there may not be much left for heating at home.

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