Heat Pump vs Gas Boiler: How Do They Compare?

April 27, 2022 | Gas Boilers, Heat Pumps

Heat Pump vs Gas Boiler: How Do They Compare?

If you’re considering which way to heat your home, you may be wondering whether you should stay with traditional gas boiler technology or go for the more modern heat pump.

When it comes to heat pump vs gas boiler, the technologies are extremely different, although in theory at least, the result is the same – central heating and hot water. Here, we take a closer look at both of these options so you can make a well-informed decision about which one you should choose to warm your home.

The Key Differences Between Gas Boilers And Heat Pumps

Gas boilers and heat pumps produce different kinds of heat. Boilers produce lots of heat very quickly that has a high temperature difference. Therefore, boilers work with radiators at a high temperature.

Conversely, heat pumps produce heat quite slowly and the temperature difference is smaller. As the heat pump produces lower temperatures, emitters or radiators require a far bigger surface area so that it in effect becomes a convector instead of a radiator. Emitters like underfloor heating are perfect with a heat pump since they run at lower temperatures than regular radiators.

Boiler systems run with average flow temperatures of 70 degrees Celsius however there is a difference in temperature between the water entering and existing the radiator of 10 degrees Celsius. So, in effect, the water exiting the radiator is 10 degrees Celsius cooler than the water entering the radiator.

Heat pump systems, on the other hand, ideally have a typical temperature of about 37.5 degrees Celsius. The temperature difference is only around 5 degrees Celsius. Therefore, the water leaving the emitter is only 5 degrees cooler than the water that entered it.

If you go for a heat pump instead of a boiler, the radiators must be very precisely sized. Also, you have to have the ability to control the water’s speed inside the circuit together with the heat delivery to the circuit.

This balance is vital and may not be possible in an energy-hungry or older property. If you decide to get rid of your existing gas boiler and get a heat pump instead, your existing pipework and radiators are almost certainly going to need updating too.

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Which Kind Of Property Is Best Suited To A Heat Pump And Which To A Gas Boiler?

To optimise heat pumps, a property needs a lot of good insulation. Ground source heat pumps are best for larger homes, while air source heat pumps are most suited to properties under 300 square metres.

A gas boiler is best for producing fast heat in less efficient, older buildings (like many of the residential properties in the UK).

In new-build properties, installing a heat pump isn’t too challenging, but in existing properties, retrofitting a heat pump is far more expensive and more complicated.

What About Cost?

If you are installing an air source heat pump at a new-build home, it will cost between £8000 and £16000. To install one at an existing home it will cost as much as £28,000 since much of the pipework and radiators will require replacing. A ground source heat pump will cost about £14000 – £25000 to install, and even more if a large borehole collector is required.

On the other hand, a regular combi boiler will only cost around £1000 – £2000 depending on which make and model you choose. With installation coming it at around £1000, the total cost comes in at about £2000 – £2000. Needless to say, that is far cheaper than a heat pump.

Space Requirements

Gas boilers don’t take up a lot of space in a home. They can usually fit easily into a cupboard or on a wall inside the home. Heat pumps, on the other hand, require different equipment. An air source heat pump has a large box which must be fitted outside the property containing a compressor and fan. It will require about 2m of empty space in front.

You’ll also require space inside your property for a control box, hot water cylinder, and maybe an additional buffer tank. If you opt for a ground source heat pump, you’ll need pipework to be buried under the ground outside your home (but not under any tree roots, near services, or underneath any buildings).

This will take up around 50-100 square metres of space per kW, so on average, you’ll need around 400-800 metres squared for a typical 8kW ground source heat pump. The GSHP’s engine will be inside the property and can be similar in size to an under-counter fridge or an American-style fridge freezer depending on which brand and capacity you choose. Furthermore, there is a buffer cylinder and hot water cylinder to consider.

As you can see from the above, at the moment, gas boilers represent the best option for most homeowners in the UK. To find out more about choosing the most energy efficient and cost-effective boiler for your needs, get in touch with the Rowlen team today.

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