Sep 2021 Heat Pumps

The urgency around climate change is spurring both governments and citizens to find ways to lower carbon emissions. A big part of that will be the ways in which we heat our homes in the future. With the government committed to banning boilers being installed in new build homes from 2025, we could all soon become more familiar with heat pumps. They are a more environmentally friendly choice than traditional gas boilers but come with their own pros and cons. 

In this article we’ll take a look at which system will work best for your home.

Heat Pumps and Boilers: What’s the Difference?

Most UK homes currently have a gas boiler to provide heating and hot water. They usually use gas as fuel for combustion, though some boilers use oil, electricity or biomass such as wood pellets. The boiler heats water by pumping it through pipes over a series of gas flames and then through your home via radiators and to water outlets such as taps. Most homes nowadays have combi boilers, which remove the need for a separate hot water tank.

Heat pumps may appear very different from traditional boilers, but ultimately perform the same function, which is to generate heat in order to produce hot water for your home. Heat pumps extract heat either from the air or the ground and transfer it to a coolant which is compressed until it reaches the correct temperature to heat the water for your home. 

How Do They Compare?

While you won’t be forced to replace your gas boiler with a heat pump after 2025 if you already have one, you may want to consider making the change anyway. The following comparisons will help you to decide.

Space Required For Installation

Air source heat pumps require you to have a small amount of outside space, as the outdoor unit is about the size of a washing machine. There is usually an indoor unit too, which houses the heat exchanger and pumps, and is about the same size as a traditional gas combi boiler. A ground source heat pump needs a lot of outdoor space, such as a garden or yard, as the heat loop, which absorbs the thermal energy, has to be buried underground. A ground source heat pump also has an internal unit, which varies in size depending on how big your home is.

Gas combi boilers are more compact as you only need a relatively small indoor unit which produces hot water on demand, plus space for the flue to exit through a wall. Combi boilers can fit in a cupboard or sit relatively unobtrusively on the wall in the kitchen or bathroom.

Cost of Installation

One of the biggest factors that stops people from installing a heat pump is the price. A new gas boiler is likely to cost between £2,000 and £3,000, including all components and labour. An air source heat pump will cost between £10,000 and £12,000, and a ground source heat pump will come in between £16,000 and £30,000. On top of this, you may have to pay more to have your house fully insulated to ensure that your heat pump is working effectively.

With up front prices like these, it is clear why many people will opt for a gas boiler instead of a heat pump. However, it is worth bearing in mind that, once installed, a heat pump is much more efficient than a gas boiler and will save you money in the long term. On top of this, heat pumps are eligible for the UK government’s Renewable Heat Incentive (RHI) scheme, where those who join receive quarterly payments every seven years for the amount of renewable energy their home produces. This means that you can recoup the cost of your heat pump within 10-15 years of having it installed.


When it comes to efficiency, heat pumps win hands down. If you have an old boiler it will generally be between 50-75% efficient, meaning that between a quarter and a half of the energy it produces is wasted. Newer boilers can achieve up to 92% efficiency, which is much better, so upgrading to a newer model could help to reduce carbon emissions.

However, when compared to a heat pump, even a brand new gas boiler cannot compare. Heat pumps can be as much as 400% efficient, because, unlike boilers, they produce a lot more energy than they consume. A heat pump can deliver 4kW of renewable energy for every 1kW of electrical energy they use, plus they emit zero point-of-use carbon, which has a hugely beneficial effect on the environment. Though gas boilers are much more efficient than they used to be, they still produce CO2 emissions, which is why the government is keen for people to change their domestic heating systems.

Running Costs

Both air and ground source heat pumps require electricity to run, which is more expensive than gas. However, due to the fact that heat pumps are so efficient, they use very little electricity so the prices are roughly comparable. Electricity prices tend to fluctuate, but, as renewable energy sources such as solar and wind power become the norm, they are likely to fall. 

Gas, on the other hand, is a fossil fuel, which means the price will only continue to rise, especially as governments become beholden to reaching their Net Zero targets, which will inevitably see price hikes on gas and incentives to greener alternatives like heat pumps.

How Long is the Lifespan?

A typical gas boiler has a lifespan of between 10-15 years, as long as it is regularly serviced. This must be done every 12 months by a Gas Safe registered engineer, which can be costly, especially if new parts are required. Heat pumps have a lifespan of 15-25 years and require little maintenance. General checks can be done by the owner on an annual basis, with a check by a professional installer needed once every three years.
The choice between a heat pump and a gas boiler is likely to depend on your budget, how suitable it is for your home and the environmental impact. However, if the financial outlay of a heat pump is too prohibitive at this stage, you can make a real difference by having a new, high efficiency boiler installed instead. For more information on having a new heating system installed in your home, get in touch and chat with one of our friendly team.