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Air source heat pump running costs

An air-source heat pump is a form of renewable energy technology that absorbs heat from the outside air to power heating and hot water inside a home. It is essentially a refrigerator in reverse. There are many benefits to having this type of renewable heating system installed, but its easy installation and low running costs are two key factors homeowners should consider.

What factors impact the cost of running an air source heat pump?

Installation is just one part of the cost when it comes to getting an air source heat pump. You must also take into account the monthly and annual costs of running this style of heating system. There is no guarantee of a fixed or definite cost, as it will vary from one home to another. Having knowledge of these factors will help you maximise your savings without compromising on the ability to keep your property warm. The below factors that affect the cost of operating an air source heat pump are closely interrelated.

  • Heat demand – this varies from one property to another and refers to the level of heating power needed for keeping a home at the optimal temperature.
  • Air source heat pump efficiency – this is the ASHP’s ability to effectively heat a house using as little electricity as possible. It is also referred to as the Coefficient of Performance (COP).

As well as the two factors listed above, the cost of electricity should also be thought of when installing an air source heat pump. These types of systems use a small amount of electricity to work, but the cost per unit of electricity can affect the annual cost of the pump.

Heat demand

Heat demand is the most obvious factor that can have an effect on the running cost of your air source heat pump. You should consider what is needed to heat the property, how many rooms there are, and what the desired optimal temperature is. The more energy you require, the bigger your heat pump, and the higher the cost will be of operating the system because of the increased use of electricity over time.

Air source heat pump efficiency (COP)

The efficiency of the air source heat pump is a much more complex factor than the heat demand in terms of its effect on the overall cost of your heating system. This style of heat distribution can have a direct impact on the system’s general efficiency. A useful example of this is when your heat pump is installed with an underfloor heating system. It will lower the amount of work that the pump needs to do in order to generate the desired indoor temperature.

Another important factor is the building’s insulation, you will need to invest in proper insulation for your home. If you don’t, it will increase the demand for heat and will need more electricity to produce heat. The more heat you can preserve, the lower the running cost of heat pumps because they don’t have to work as intensely. Also, where you have your air source heat pump located can also affect its efficiency. You should select an area that is free from blockages and preferably well exposed to sunlight, so it will be more effective in creating heat.

How much electricity does a heat pump use?

As previously stated, the efficiency of a heat pump is measured in COP. This unit is calculated by measuring the level of energy inputted (in this case, electricity) and the amount of energy (heat) that is outputted. An air-source heat pump that has a COP of three can produce three KW of heat from every one KW of electricity.

The average house requires roughly 12,000-kilowatt hours (Kwh) of heat per year. So, in order to achieve this, a heat pump with a COP of three would have to use 4,000 kWh of electricity each year. This figure will be based on the size of your home, how well it is insulated, how much hot water you use as well as the efficiency of your pump. A heat pump with a COP of four would use less electricity to generate the same amount of heat.

At 4,000 Kwh of electricity with the price being £0.28 per unit, it will cost you about £1,120 in your annual heating bill (based on average electricity prices as of April 2022).

In what ways can you lower your electric bill with a heat pump?

Even though your energy bills will likely reduce if you change to a heat pump, your electricity usage will increase. Fortunately, there are some ways you can limit your heat pump’s energy consumption and reduce your electricity bill.

Avoid changing the set temperature

When you regularly turn the temperature up or down depending on how hot or cold you are, the heat pump will use more power. Whereas, when it stays at the same temperature it will use less power. It would be beneficial to set the thermostat to a certain temperature and don’t alter it.

Check the water heating temperature

If this temperature is set to high, your heat pump will be using more power to get the water to the right temperature. You can lower the temperature of the water to 40 degrees or lower, which will still be enough to heat your home in an effective way.

Properly maintain your heat pump

Inadequate maintenance of your air source heat pump could result in a 25% increase in your energy bills. Dirty and blocked filters reduce the level of airflow that can move through the system and could harm the performance. Your heat pump should be serviced every year.

How much does a heat pump cost per hour?

A 2.2kw air source heat pump will create roughly about 11kw worth of hot water for radiators and use 2200 watts from the mains. With a cost of 28p per Kwh (based on average prices as of April 2022), running this system would cost you around 62p per hour in electricity, or £4.96 for an 8 hour ‘running period’. However, a bigger central system consuming about 11kw would be quite expensive, costing nearly £3.08 per hour to run, but this will create enough heat to warm an average-sized three-bedroom home.

How can you save on ASHP running costs?

There are a lot of incentives in place from the government to promote the installation of more renewable heating systems in the UK. You can qualify for these when you install renewable heating technology like air source heat pumps. You should take advantage of these schemes to help offset the cost of fitting your new air source heat pump as well as ongoing running costs.

You can also follow the below steps to increase the efficiency of your air source heat pump. 

  • Install double or triple glazing windows to prevent heat loss
  • Install cavity wall insulation to stop heat from escaping through your walls
  • Have loft insulation installed to restrict heat loss through your roof
  • Keep windows closed as much as possible to avoid drafts
  • Change to a cheaper electricity supplier or install a solar PV system
  • Fit bigger radiators
  • Install underfloor heating
  • Conduct an annual heating system check throughout the many years of life expectancy of your air source heat pump to ensure the system is running efficiently

If you get a heat pump grant the initial purchase cost of your heat pump will be significantly reduced, apply now in less than 60 seconds.

(Article updated to reflect average electricity prices as of April 2022)

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.