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Myths About Air Source Heat Pumps Debunked

Top 8 myths about Air source heat pumps debunked

Make no mistake, we love air source heat pumps! This is why we feel the need to challenge the myths we hear time and again about these fantastic machines. Some truths we spill here may surprise you; some may enlighten you, but hopefully once you’ve read this, you’ll love these big fans as much as we do. 

With a 5th of the UK’s carbon emissions coming from heating buildings, it’s clear we need to think about different ways of heating our homes.  

Air source heat pumps are a clean way to heat your home without burning fossil fuels and can play a huge role in reducing our dependency on gas and massively lower the greenhouse gases we produce.  

When combined with a solar system, they also have the potential to reduce your bills too. 

Despite their potential, there’s a lot of misinformation out there with myths spread about heat pump’s effectiveness and performance through social media and even some news outlets.  

Some of these claims are completely false and easily proved incorrect, but a couple do possess a slither of truth. That said, with a better understanding of the technology and how to live with one, even these halve truths can be debunked. 

There’s a reason that 81% of heat pump owners surveyed by Nesta last year in the UK’s largest air source heat pump satisfaction survey (over 2,500 owners), said they were as satisfied or more satisfied with their heat pump compared to their previous heating system. 


air source heat pump

Importantly, the people surveyed lived in homes of all shapes and sizes, new and old with the results finally putting to rest one argument that you need a brand-new home to benefit from a heat pump. 

These people are now enjoying gas free heating, and we’d like to think with a bit more fact-based information about air source heat pumps, people will quickly realise they are a much more attractive alternative to gas guzzling combi boilers. 

Encouragingly, in 2023 more people in the UK than ever before switched to an air source heat pump with 220,000 installations, a 20% increase. 

If you’d like to read some independent reports from heat pump owners from across the UK, this recent article in the Guardian has some insightful reviews of heat pumps in the real world and how they perform.  

Ready to change your mind about air source heat pumps? Here we go! 

Myth #1: Heat pumps don’t work in cold weather 

We hear this time and again and we can see why people may not understand how you can get heat from cold air. But it’s not too complicated.  

Air source heat pumps contain a refrigerant that absorbs the outside air, a compressor then compresses the refrigerant which raises its temperature and then circulates it around a home’s central heating and water system.  

They can do this with outside air as cold as –20°C 

Further proving this myth as an untruth is the fact that the most per capita heat pumps can be found in the world’s coldest climates.  

Despite frequent claims in parts of the media that heat pumps do not work when its chilly, in Europe, the four countries with the largest share of heat pumps are Norway (60% of households), Sweden (43%), Finland (41%) and Estonia (34%). These four nations also face the coldest winters in Europe.  

Myth #2: Heat pumps need a backup heating system to keep you warm 

No, they don’t 😁. While it is true that heat pumps can become less efficient in extremely cold temperatures, they don’t stop working, they just need more energy to produce heat just like gas boilers work harder when the temperature drops. Modern heat pumps are also extremely well suited to adapt to the cold weather and use as little energy as possible when things get chilly. 

Heat pumps come in lots of shapes and sizes just like gas boilers do to suit the home they are heating, so if your heat pump is designed for your house, you can rest assured it will be heating your home just fine on its own. 

The fact air source heat pumps have to work harder in winter has got many heat pump haters into a bit of a twist with them deciding that this increase in energy will send your electricity bills soaring, but you wouldn’t put a combi boiler designed for a 2 bed flat in a mansion as it wouldn’t be up to the job. The same goes for heat pumps. 

Of course, insulation is important to keep the heat in, but less than you’d think. More on that later. 

Myth #3 – Heat pumps use electricity, which is much more expensive than gas.  

Ready to get technical? Us too. Heat pumps generate much more heat than the electricity used to power them. Over a whole heating season, this is calculated as a Seasonal Coefficient of Performance (SCOP) and is a measure of the efficiency of heat out versus energy in.  

A modern gas boiler is 85-90%, and a heat pump is typically 350-400%, more than three times more efficient. This means that at current prices, a heat pump’s operating cost is comparable with gas boilers over a year and cheaper than others such as LPG, direct electric boilers, electric storage heaters or oil.  

When combined with a solar system and battery, that’s when you’ll really see the savings roll in as you can generate much of the power you need for your heat pump from the sun. 


airsource heat pump myths

Myth #4: Heat pumps don’t work in old or existing buildings 

Takes a breath…. This old chestnut.  As we covered in the intro, a huge independent UK survey in 2022 of people who switched to air source heat pumps showed a whopping 81% of owners were just as happy, if not happier, with their heat pumps than their old heating systems – and that’s regardless of how old or what type of house they lived in.  

In fact, 83% of owners living in Victorian or older properties were satisfied or more than satisfied with their air source heat pump. This tells us that heat pumps are effective across the range of residential property types in Britain. 

The survey also uncovered that while some people take the opportunity to insulate their homes at the same time they get a heat pump, this is not universal. Only 55% of users who had a heat pump installed also undertook insulation upgrades, such as loft insulation, wall insulation and double or triple glazing. 

Again, the success of an air source heat pump comes down to selecting the right unit for your property.  

Myth #5: Your house needs to be completely insulated.  

Clearly, the less energy needed to warm your home the better, and if your home retains heat through insulation then your heating source doesn’t have to work so hard, so good insulation to reduce heating energy demand always make sense.  

But this applies to all heating systems, not just heat pumps. A brand-new gas boiler in a draughty uninsulated house will need to work very hard to get rooms comfortably warm and maintain that temperature. 

Fortunately, houses do not have to be extensively renovated before installing a heat pump. Of course, the lower the heat losses, the more efficient a heat pump can operate so the efficiency of the heat pump can be increased dramatically with the help of additional, relatively inexpensive short-term measures.  

Easy upgrades include replacing older radiators and installing loft insulation.  

Radiators are important to understand as heat pumps have a lower operating temperature than boilers, it’s one of the reasons they are so energy efficient. So, to make sure a room is warm, larger radiators are sometimes needed. Remember a larger radiator running at a cooler temperature will still perform as well in heating a room as a smaller one at a higher temperature but will need less energy to maintain that temperature. 

The key to success is using an installation company that conducts a room-by-room survey to calculate each room’s heat loss. Then the heat pump chosen should be sized to provide all the heat required for the house, along with making sure the radiators have enough surface area to provide the necessary amount of heat.  

This process is specified under the Microgeneration Certification Scheme (MCS), which all reputable installers should hold, and you should not use a company that doesn’t adhere to the MCS guidelines. 

Understanding how your home is losing heat is crucial to any plans you have to make your home more efficient. Heat pumps, and radiators if correctly sized and installed, will give you all the heat you need.  

Avoiding unqualified companies that install the wrong size heat pump or do not conduct a room-by-room survey to assess if new radiators are needed is often the reason people feel their heat pump is not performing.  

Myth #6: Heat pumps need to run for long periods 

This is partly true, but you need to hear the whole story. Let us explain. 

It’s important to remember that air source heat pumps are not the same as gas boilers, even though both share the common goal of maintaining a warm living space. Understanding the unique way heat pumps work is key to maximising their efficiency.  

Unlike the rapid heating process, you get with firing up a gas boiler, heat pumps operate at a lower flow temperature, taking slightly more time to get a room warm.  

This deliberate pace is key to their design and contributes significantly to their energy efficiency. Air source heat pumps deliver a consistent, steady flow of warmth to radiators, which, while slower than the rapid cycles of a gas boiler, is markedly more efficient providing adequate insulation is in place.  

The traditional inefficiency of gas boilers, is seen by how they heat to high temperatures, shut down, and then restart when temperatures drop. Compare this to the continuous monitoring and adjustment capabilities of heat pumps.  

Heat pumps never fully power down; instead, they adapt to outdoor and indoor temperatures, maintaining a stable climate within the house. This operational continuity, coupled with the energy-efficient performance of modern air source heat pumps, ensures a consistently warm home with minimal energy consumption.  

So, even if you’re away all day, rest assured that the heat pump will efficiently ensure a cosy home upon your return. 

Myth #7: Heat pumps are noisy  

Not true. Remember heat pumps have been around for over 100 years and older units were a little noisy, unfortunately that image has stuck for some people. The reality is that modern heat pumps are designed to run almost silently, with sound levels similar to a fridge or a desk fan.  

Myth #8: Heat Pumps Are High Maintenance   

Sorry, no they’re not. Once installed, your heat pump requires very little maintenance. They are safer than gas, oil, or LPG systems because they don’t use flammable fuels, and there is no risk of carbon monoxide accumulation. They also have fewer moving parts so there is less to go wrong. 

They require an annual check-up just like your boiler but other than that, they are pretty self-sufficient. 

In addition, a modern air source heat pump has an expected service life of 25 years which is double that of a traditional gas boiler.   

Still not convinced? Here are a few more facts about air source heat pumps. 


  • A qualified Heat pump engineer can install a heat pump in virtually any home in the UK and connect directly to the existing central heating system.
  • They’re simple to use and combine smart technology meaning you can control all aspects of your heat pump from your phone. 
  • In a recent survey by Octopus Energy of their customers, 79% said it costs the same to run or less than their old gas boiler 
  • Thanks to the government’s boiler upgrade scheme, everyone can get a £7,500 grant towards a heat pump installation meaning they cost about the same to you as a combi gas boiler 
  • Heat pumps don’t take up much space, you’ll need roughly 1m x 1m x 2m (or to help you visualise – the size of a moped) outside and around a meter in-front and to each side to breathe. 
  • Inside you need space for a hot water tank – 2m x 1m x 1m (the size of a modern fridge freezer), on the ground or first floor of your home (the closer to the outside the better). The cylinder can also be installed in a garage, outdoors in a purpose-built store 

Interested? Give us a call, one of our experts can answer any further questions you have and also tell you about some of the other amazing heat pump grants that are available. 

Alternatively, just click below to see if you could qualify for an air source heat pump grant along with solar and insulation upgrades. 

See if you're eligible for free air source heat pump grant
See if you're eligible for free air source heat pump grant
Athira Harish

Athira Harish