Oct 2021 Heat Pumps

As we become more aware of climate change and the need for clean, green energy, many people are considering air source heat pumps as an alternative to traditional gas or oil boilers. In this article we’ll explore the pros and cons of choosing an air source heat pump when making the choice about the best way to heat your home.

How Do Air Source Heat Pumps Work?

Traditional heating systems either burn fuel or convert electricity into heat, but heat pumps are different as they don’t actually generate heat. Instead, they collect existing heat energy from outside your home and move it inside. This makes them an efficient method of heating, as they deliver more heat energy than the electrical energy they consume. 

Air source heat pumps are often described as working like a refrigerator in reverse. Air from outside is blown over a network of tubes filled with a refrigerant. As the refrigerant warms it is changed from a liquid into a gas, which is then passed through a compressor to increase its pressure. As well as adding pressure, compression adds more heat, and these hot gases travel into a heat exchanger, where the refrigerant transfers its heat to the cool air or water within it, depending on the kind of heat pump you have. This air or water is then circulated around your home to provide heating and hot water, while the refrigerant condenses back into a liquid and the whole process starts again.

Air-to-water heat pumps are the most common model used in the UK. This type of system distributes heat via your wet central heating system, which means they fill radiators and underfloor heating systems with water and heat the water in your taps, the same as a gas boiler would. Air-to-air heat pumps require a warm air circulation system to move the heat around your home, and they don’t provide hot water. Air-to-air heat pumps aren’t eligible for the government’s Renewable Heat Incentive scheme, which provides financial support to people installing heat pumps, so they may not make practical or financial sense for many households.

What are the Pros of Having an Air Source Heat Pump?

Having an air source heat pump installed in your home provides some excellent benefits that you don’t get with traditional boiler systems. These include:

  • Save money on energy bills. Having an air source heat pump fitted means you will spend less money on energy bills as you are using the outside air for heating, rather than buying energy from a company. Air source heat pumps do require a small amount of electricity to run, but the cost of this will be easily recouped by having lower heating bills.
  • Lower carbon footprint. Air source heat pumps are a form of low carbon heating, because they don’t rely on the burning of fossil fuels to produce energy. 
  • Eligible for financial aid. You can receive payments from the government through the Renewable Heat Incentive scheme, which has been extended to March 2022. This can help you to recoup the initial financial outlay for the heat pump.
  • Easy to install. Compared to ground source heat pumps, which require digging up your garden, air source heat pumps are very easy to install. It doesn’t require planning permission and can be done in as little as two days. 
  • Low maintenance. Air source heat pumps require servicing by a professional installer once a year, but aside from that most maintenance tasks can be done yourself. This will include jobs such as cleaning filters, checking for leaks, checking refrigerant levels and clearing leaves, dirt and debris from your pump.
  • Long lifespan. Air source heat pumps last a long time and, with proper maintenance, can last 20+ years. Most pumps also come with a five year warranty. 
  • Can be used for cooling too. If you choose an air-to-air heat pump you can use it to cool and circulate air around your home during the summer months. With temperatures on the rise, this could be a big benefit.

What are the Cons of Having an Air Source Heat Pump?

Of course, there are also some down sides to having an air source heat pump fitted. These include:

  • Lower heat supply than traditional boilers. Air source heat pumps supply less heat than traditional boilers, so larger radiators may need to be fitted. Water from boilers tends to reach a higher temperature than that from a pump, so a larger heat emitting surface area may be required to reach the same temperatures.
  • Extra cost due to the need for underfloor heating. Due to the lower heat supply, air source heat pumps work best when used with underfloor heating. This is because underfloor heating doesn’t need to reach high temperatures, like radiators do. If you don’t already have underfloor heating you’ll need to pay extra to have it installed.
  • Extra insulation may be necessary. In order to reap the full benefits of a heat pump, your home needs to be very well insulated. If heat is escaping from windows, doors, walls or the roof, it will be difficult to heat your home to a high enough temperature to be comfortable.
  • Air source heat pumps can be noisy. When in operation, a heat pump can be noisy, comparable to an air conditioning unit or heavy rain. If you have trouble with noise or are a light sleeper, having one in your home could pose a problem.
  • Lower efficiency below 0 degrees C. Air source heat pumps can operate at temperatures as low as -20 degrees C, however once you get below 0 they begin to lose efficiency. If you live in a particularly cold area a ground source heat pump may be a better option as the pipes are buried underground which maintains a more stable temperature.

Having an air source heat pump installed comes with both positives and negatives but overall there are far more benefits to outweigh any minor problems, not least the fact that they don’t rely on gas, which is a fossil fuel. Air source heat pumps are becoming a mainstream choice that can both save you money and help us all fight climate change.