Myths about heat pumps

Heat pumps will be a critical technology to get us to net zero by 2050 but social media is full of myths about heat pumps. Dr Jan Rosenow busts 25 of those myths.

Heat pumps are playing a major role in the electrification of everything and are increasingly being used to replace gas heaters and boilers. 

Most modelling suggests they will be the critical technology to get us to net zero by 2050.

The International Energy Agency predicts a huge global boom in the sale and uptake of heat pumps, as consumers seek out more energy efficient – and less costly – ways to heat water and their homes.

2022 saw record growth in heat pump sales in Europe and in the US with the sale of heat pumps surpassing the sale of gas heaters for the first time.

Heat pumps can be used for both water heating and space heating. Reverse cycle air conditioners which are commonly used in Australia are a type of heat pump.

Heat pump technology allows for the efficient transfer of heat from one location to another. Water heat pumps extract heat from the surrounding air, ground, or water and transfer it to heat the water stored in a tank, using an electric compressor. Heat pumps designed for space heating extract heat from the outdoor air or the ground and transfer it into a building to provide heating, or remove heat from indoors and transfer it outdoors for cooling (air-conditioners).

But social media and mainstream media are flooded with myths about heat pumps.

One of the world’s leading experts on heat pumps and the energy transition is Dr Jan Rosenow, the Director of the Regulatory Assistance Project, an independent global team of highly skilled energy experts.

Here he busts 25 myths about heat pumps.

Myth 1: “Heat pumps don’t work in cold climates.” 

False. The majority of heat pumps can be found in the coldest climates. More than half of all households in Norway have one.

Myth 2: "Heat pumps don't perform when it's cold." 

Mainly false. Even at temperatures below freezing heat pumps still perform well as field data shows. For very cold temperatures well below freezing hybrid systems may be needed.

Myth 3: “Heat pumps don’t work in existing buildings.” 

False. From long-standing research: “The research results clearly show that heat pumps as heating source function reliably also in existing buildings. As a rule, the units worked flawlessly.”

Myth 4: “Heat pumps don’t work in old buildings.” 

False. Recent results from the UK indicate that there is no significant variation in performance based on house age. I also had a heat pump in my home built in 1880 since 2019 performing very well.

Myth 5: “Heat pumps cost more to run & increase heating bills.”

This depends on energy prices in your country. The IEA produced a handy interactive calculation tool that allows you to explore and compare the economics of different residential heating systems.

Myth 6: “A heat pump needs to stay on all the time.” 

You never switch the heat pump off manually but this does not mean the heat pump is operating all the time. The system automatically adjusts to outside and indoor temperatures and ramps down when it is warmer.

Myth 7: “Heat pumps work with underfloor heating only.” 

Heat pumps work well with radiators too. In some cases radiators may need upgrading. But it has been common practise in recent years for heating installers to 'oversize' radiators.

Myth 8: “Heat pumps won’t keep you warm.”

Households who installed a heat pump report that they are as comfortable or more comfortable than before the installation in a survey by @CoolproductsEU – 81% have seen the level of comfort improve.

Image: Cool products for a cool planet

Myth 9: “Heat pumps are noisy.” 

Ground source heat pumps make very little noise. Air source heat pumps can be quiet too as this video shows. Also remember: in the summer when you're out in the garden heat pumps usually don't run as no heating is required.

Myth 10: "Heat pumps only work in highly insulated buildings." 

False. Houses do not have to be extensively renovated in order to allow for an installation of a heat pump. But good fabric efficiency offers energy system benefits and keep costs down.

Myth 11: "Turning gas to electricity to heat via a heat pump is less efficient than burning gas in a boiler." 

False. At SCOP 3 a heat pump even if running 100% on gas electricity needs ~1/3 less gas to make the same amount of heat than a boiler. Heat pumps reduce gas even if they use electricity from 100% gas. Professor Sir David MacKay said this already in 2008: "Heat pumps are superior in efficiency to condensing boilers, even if the heat pumps are powered by electricity from a power station burning natural gas."

Myth 12: “Heat pumps devalue properties.”

False. The evidence suggests the opposite. Heat pumps increase the value of properties. “Residences with an air source heat pump enjoy a 4.3-7.1% (or US$10,400-17,000) price premium on average.”

Myth 13: "Heat pumps are unaffordable." 

Partially true. But many countries offer subsidies for heat pumps & with running costs included heat pumps can offer lifetime savings over fossil fuel systems. But it depends on the country. Some examples.

Myth 14: "The grid cannot cope with heat pumps." 

Partially true. In many places there is capacity in the grid to supply electricity for more heat pumps. But with significant heat pump uptake electricity demand will grow and grid investment is needed.

Myth 15: "Heat pumps are the only low carbon solution for heating." 

False. Better fabric efficiency (building insulation) and district heating are very important too and can offer large system benefits in terms of flexibility and system benefits.

Myth 16: “Heat pumps cannot be installed in small apartments.”

False. There are projects where tower blocks use ground source heat pumps, for example, from @KensaHeatPumps and large heat pumps can fuel district heating networks connecting apartments.

Air to air heat pump for heating and hot water outside an apartment block (Image: Perytskyy, iStock)

Myth 17: "Heat pumps will just run on fossil fuel electricity." 

False. It is true that most power grids still include a lot of fossil generation. But every year substantial amounts of renewables are added to the grid driving out fossil generation.

Myth 18: "You will freeze during a power cut and be better off with a gas boiler." 

It is true that during a power cut heat pumps cannot function. But the same is the case for a gas boiler.

Myth 19: "There is no consumer demand for heat pumps." 

False. 2022 saw record growth in heat pump sales in Europe and in the US for the first time more than 4 million heat pumps were sold surpassing gas furnaces for the first time.

Myth 20: “Heat pumps don’t work with microbore piping.”

Only partially true. Microbore piping (any piping smaller than 15 mm diameter) is not ideal but as @heatgeek points out it can work with a heat pump under certain conditions.

Myth 21: "Heat pumps are new and untested technology." 

False. The first heat pump as we know it today was built by Peter von Rittinger in 1856. Heat pumps were put in peoples' homes already many decades ago.

Myth 22: "You can just plug in heat pumps and forget about insulation." 

Mainly false. Yes, heat pumps can heat any building even if uninsulated. But at significant cost. Modest building efficiency improvements always make sense also for fossil heating.

Myth 23: “Heat pumps don’t last long.” 

False. Heat pumps have long lifetimes and can exceed 15 or even 20 years if well maintained.

Myth 24: "Heat pumps will never offset carbon emissions from making them." 

Mainly false. It depends on local electricity mix. In most of Europe after short period of time embodied carbon will be offset by operational emission savings. Here is an example from the UK:

Jan Rosenow, @janrosenow

Myth 25: “Heat pumps will always need a backup heating system to keep you warm.” 

False. 79% of homes monitored under the UK’s electrification of heating trial have no backup heating system installed and use a heat pump to provide all of the hot water and space heating needs.

Originally published on Twitter @janrosenow

Dr Jan Rosenow
October 15, 2023
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