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How does a heat pump work?

‘How does a heat pump work?’ is one of the most common questions we are asked. Air source heat pumps work in a very similar way to your fridge, with air extracted from outdoors used to heat your home and to create hot water.

In this article, we’ll explore how an air source heat pump works in more detail, including discussing the temperatures at which heat pumps are most effective. We’ll also investigate whether a heat pump can really heat a whole house, helping you to make the decision as to whether a heat pump is right for your home.

What is a heat pump?

Heat pumps are often seen as a modern and environmentally friendly alternative to a traditional gas boiler. They are powered by electricity rather than gas and use refrigeration technology to heat a home.  

A heat pump is usually combined with a thermostat which detects the temperature inside your home and automatically triggers the heat pump to heat your home to the desired temperature. This helps to keep your home at a consistent temperature that is comfortable for you and your family.

But how do air source heat pumps work and how do you know if a heat pump is right for your property? Read on to find out.

Wondering if a heat pump is right for your property? Contact us to find out

How do air source heat pumps work?

Air source heat pumps work similarly to a refrigerator, except they heat rather than cool. Let’s take a look at the process that a heat pump goes through to heat your home or your hot water.

  1. Air is drawn in from outdoors and passes over pipes containing liquid refrigerant.
  2. The refrigerant will begin to heat up, transforming into a gas.
  3. The refrigerant gas will flow into a compressor, where the pressure will be increased. This will heat the refrigerant gas further, increasing the temperature.
  4. After being compressed, the gas will progress into a heat exchanger. Here, the hot refrigerant gas will transfer its heat to the surrounding air and water. The heated air and water then circulate around your home to provide both heat and hot water.
  5. As the heat is transferred from the refrigerant to the cold air and water, the refrigerant gas will condense back into a cool liquid. The cycle will then begin again.
Do heat pumps work in winter

Do heat pumps work in winter?

Many people are concerned that air source heat pumps will not work during the winter months, when the temperature is cooler outside. This is a valid concern, as the heat pump extracts the warm air from outdoors to bring it inside your home.

Despite the air outside feeling cold in winter, there is still some ambient heat in the air, even when temperatures are below freezing. Your heat pump works by extracting this heat from the air and using it to heat the refrigerant liquid.

When the temperatures are lower, your air source heat pump will need to work harder. This means that your heat pump may be less efficient during the winter months. However, your heat pump should still be effective even at temperatures as low as -20 oC.

So, your air source heat pump doesn’t just rely on outdoor temperatures, but it will need to work harder to heat the air if the temperatures outdoors are lower. This means that it will become less efficient during the winter months.

Considering an air source heat pump? Find out if it’s right for your home here

What temperature is a heat pump not effective?

The temperatures at which an air source heat pump is able to operate will depend on the brand and model of heat pump that you choose. However, the majority of heat pumps will be able to operate in outdoor temperatures as low as -20 oC.

In the UK, it is rare for outdoor temperatures to drop below -10 oC. This means that your heat pump should still be effective in heating your home in even the coldest of British winters.

Pros and cons of a heat pump

Pros and cons of a heat pump

The decision of whether to invest in a heat pump can feel overwhelming. It’s important to carefully consider the pros and cons of installing a heat pump before making your decision.

To help you to make the right choice for your property, we’ve put together a list of the key advantages and disadvantages of installing an air source heat pump in your property. After all, you need to understand both sides before you can make an informed decision.

Advantages of heat pumps

Air source heat pumps are currently soaring in popularity in the UK, thanks to their many advantages. Here are just a few of the benefits of installing a heat pump in your home.

  • Reduced running costs: Heat pumps are typically cheaper to run than an average gas boiler, meaning that you could see a significant reduction in your energy bills by installing a heat pump in your home.
  • Increased safety: Gas boilers can be dangerous if they are not maintained properly. If a gas boiler malfunctions, it could lead to carbon monoxide leaks, causing a health hazard. Heat pumps do not have this issue, as they operate solely on electricity rather than gas, enhancing safety in your home.
  • Reduced carbon emissions: It’s essential to consider the environment in today’s modern world. Luckily, heat pumps prioritise the environment, reducing carbon emissions and allowing you to do your part in helping the environment.
  • Extended life span: Whilst many boilers only last for an average of 10 years, heat pumps typically last for an average of 20 years. In fact, a properly maintained air source heat pump could last for up to 25 years.
  • Reduced maintenance: A gas boiler needs to be serviced by a professional every 12 months to ensure its safety. In contrast, a heat pump can be checked by a professional less frequently (typically every 3-5 years) as there are no safety concerns with air source heat pumps.

Disadvantages of heat pumps

Whilst there are many advantages of heat pumps, there are also some disadvantages that you need to be aware of. After all, you can only be sure that you’re making the right decision if you have weighed up both the pros and cons.

Here are the disadvantages of installing an air source heat pump in your home.

  • Higher upfront cost: Air source heat pumps typically have a higher upfront cost than a gas boiler. However, this is offset by the extended life span and the reduced maintenance requirements, as well as the energy savings over time. There are also government grants available to help to reduce the initial costs of installing a heat pump in your home.
  • Difficult to install: Heat pumps are more complex to install than a standard gas boiler, which means that the installation time for your heat pump is likely to be longer than if you were directly replacing your boiler.
  • Lower efficiency in cold weather: As air source heat pumps extract heat from the air outdoors, they are less efficient during the cold winter months. However, they are still capable of heating a house, even at temperatures as low as -20 oC – they just have to work a bit harder.
  • Planning permission sometimes required: In the majority of cases, you will not require planning permission to install an air source heat pump. However, there are some cases where planning permission may be required, for example if your property is listed. Choosing a reputable and knowledgeable company to install your heat pump is the best way forward, as they will be able to advise you on whether you will need planning permission for your installation.

Contact a heat pump professional to discuss your heat pump installation here

Can a heat pump heat a whole house?

If you’re thinking about installing a heat pump in your home, you might be wondering whether a heat pump is really capable of heating a whole house. This is a common question amongst homeowners with larger properties, who may be worried about the capacity of a heat pump.

Luckily, heat pumps are suitable for almost any property, providing it has sufficient insulation. For larger properties, you may find that you require a larger heat pump, but in most cases this shouldn’t impact your installation or prevent you from making the change to a heat pump.

How warm can a heat pump get your house?

Heat pumps typically work in conjunction with a thermostat. You will be able to programme this thermostat with a minimum and maximum temperature for your property. When the thermostat registers that the temperature of your home has dropped below the minimum level, it will send a signal to the heat pump to begin heating your home.

It’s important to note that heat pumps typically operate at a lower temperature than gas boilers. Whilst a gas boiler will heat hot water to a temperature of around 75 oC, a heat pump will usually heat to around 55 oC. However, this shouldn’t be a problem, as you’d never use water at 55 oC out of the tap – a shower of this temperature would cause significant burns! Instead, a heat pump delivers lower levels of heat over a longer time period.

One benefit of this is that your home is likely to be at a more consistent temperature with a heat pump, as a lower level of heat is emitted throughout the day, rather than bursts of more intense heat from a gas boiler, which are followed by a drop in temperature.

Are heat pumps worth it

Are heat pumps worth it?

One question that we are asked on a regular basis is whether an air source heat pump is worth the investment. After all, heat pumps do require a higher initial investment than a replacement gas boiler, so you need to be sure that your investment will pay off in the long run.

Heat pumps are considered to be an environmentally friendly investment. Not only will using a heat pump help to reduce your carbon emissions, but you can also expect to see a considerable reduction in your energy bills. The environmental benefits of a heat pump can be further enhanced by combining your heat pump with a renewable energy source such as solar panels to power your heat pump during daylight hours. This will further reduce your energy bills whilst minimising your environmental impact.

Opting to install a heat pump in your property will also reduce your maintenance requirements. You’ll no longer need to shell out for an annual boiler service, as the components within a heat pump require less maintenance, as well as removing the safety concerns that are associated with gas boilers. As heat pumps can last for up to 25 years, you can relax after the installation, with a service required only every three to five years.

So, if you’re looking for a way to do your part for the environment, keep your carbon emissions to a minimum and reduce your energy bills, installing an air source heat pump might be the right decision for your household.

In summary

The world is quickly moving towards air source heat pumps as a sustainable way to heat homes and to provide hot water. Not only is this an eco-friendly initiative which can reduce your carbon footprint significantly, but it can also help to reduce your energy bills and give you peace of mind for the future.

In this article, we’ve answered the question ‘how does a heat pump work?’, as well as talking you through some of the pros and cons of installing an air source heat pump in your property. It’s important to carefully weigh up both the advantages and disadvantages of heat pumps so that you can make an informed decision for your home.

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Clive Whyte

I'm Clive, a sustainability advocate and green energy expert. I have over 25 years of industry experience and now I spend my time sharing my knowledge online with the hope of educating Britain towards a more sustainable future.