Air Source Heat Pump Efficiency

‍In Summary:

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Air source heat pumps (ASHP) typically work at 300% efficiency. This is measured as a Coefficient of Performance (CoP) rating; 1kWh of energy consumed by your heat pump would produce 3kWh of heat energy in this example. The CoP rating here is 3.

Gas boilers are incredibly inefficient in comparison. Whilst a heat pump’s efficiency will sit at around 300%, a new gas boiler will work at around 90% and older boilers can be 70% or lower. This would translate to a CoP rating of 0.7-0.9.

CoP ratings relate to an air source heat pump's efficiency, but don’t necessarily give the full picture. A better measure of your overall system efficiency is the Seasonal Performance Factor (SPF). This accounts for total annual electricity consumption and the exact heat produced as a result. 

We take into account all efficiency ratings as well as various details about your property to suggest the best possible unit. Use our heat pump tool here to see which is the most suitable ASHP for your property.

Our favourite energy efficient air source heat pumps include: 

• Samsung EHS
• Grant Aerona³ R32
• Ideal Logic Air
• Vaillant aroTHERM Plus

To help them work as efficiently as possible, you can improve your property by installing solar panels to reduce costs, ensure your pump’s airflow isn’t blocked by a cover, regularly service your ASHP, upgrade your insulation, radiators and use smart controls.

If you have questions about heat pump installation or their energy efficiency, speak to one of our experts via phone, email or chat here. 

How Efficient is An Air Source Heat Pump?

Air source heat pumps are one of the most efficient ways of producing heat for your home, working at approximately 300% efficiency. This means for every kWh of electricity consumed, an ASHP will produce around 3kWh worth of heat. 

Heat pump efficiency is measured using a unit called Coefficient of Performance (CoP), meaning in the above example, the average heat pump will produce a CoP rating of 3. 

As air source heat pumps draw air via a fan, the outdoor temperature is going to play a big role in how efficient it actually is. The higher the outdoor temperature, the easier it is for the ASHP to keep up with heat and hot water demand. 

On the flip side, during winter months when temperatures are colder, the pump has to work longer and harder, which will bring its overall efficiency rating down. 

That said, even when running at cooler temperatures of approximately -4°C to 11°C, most modern heat pumps are still able to work at 300% efficiency, so still with a CoP rating of 3.

Are Heat Pumps More Efficient Than Gas Boilers?

Heat pumps are much more efficient than gas boilers. An A-rated gas boiler will work at around 90% efficiency, whereas an eco-friendly heat pump will run closer to 300% efficiency. 

You can see on our page covering the most efficient boilers here, leading brands are now producing boilers that work at up to 94% efficiency. 

For every kWh of gas they consume, they’ll produce 0.94kWh of energy. The efficiency here is much lower than a heat pump that would produce 3kWh of energy for every 1kWh of energy it consumes. 

Bear in mind this assumes you have a modern, A-rated and efficient gas boiler. Whilst newer gas boilers will be working at 88-94% efficiency, older boilers could be working at as low as 70% efficiency. If you have a gas boiler working at 70% efficiency, an air source heat pump would be more than 4 times more efficient than your current gas boiler.

The Most Efficient Air Source Heat Pumps

Whilst the efficiency of air source heat pumps is incredibly important when deciding which one to install, so is the likes of brand reputation, after sales care and of course, picking the most suitable unit for your property. 

The best air source heat pumps for efficiency, but that also come with a long warranty from a leading brand include the likes of:

• Samsung EHS
• Grant Aerona³ R32
• Ideal Logic Air
• Vaillant aroTHERM Plus

You can read our detailed guide covering air source heat pump brand reviews here, or get a fixed price on-screen using our ASHP calculator here. 

Improving Air Source Heat Pumps Efficiency

There are dozens of ways to increase an air source heat pump’s efficiency, and these are some of the most effective. 

Install Solar Panels

Managing your heat pump’s settings to improve overall efficiency helps to reduce energy bills. But if you want maximum efficiency in terms of reducing your monthly utility bills, fitting solar panels is the way to go.

Installing a solar panel system that’s big enough to power your ASHP as well as the other electrical appliances in your home could mean your electricity bills go to zero, or very close!

We fit air source heat pumps alongside solar panel systems, and utilise government grants to reduce the overall cost; up to £7,500 in government grants in some cases. 

‍Use our heat pump tool here, and once you’ve chosen your heat pump, click the option to “Add a solar panel system”. 

Check Your Heat Pump’s Cover

A lot of households cover their heat pumps in various forms to make them look more aesthetically pleasing, and other times simply to help reduce noise. 

However, sometimes these covers mean that the fan isn’t exposed or is partially blocked, this could reduce airflow. 

Airflow restrictions lead to your pump having to work harder to heat up hot water and radiators, reducing efficiency. 

Regularly Maintain Your Heat Pump

The efficiency of a heat pump is directly correlated to its service schedule. Don’t get your heat pump regularly serviced? You’ll see a huge drop in efficiency over time. 

Typically, we’d suggest servicing a heat pump every year. Pumps that aren’t serviced regularly could see a drop in efficiency that’s as high as 25%.

A service will usually include:

• Filter cleaning, with a replacement fitted where necessary
• Checking your ASHP for any leaks, as well as refrigerant levels
• Visual check of the fan blades, as well as a quick clean
• Ensuring airflow is at maximum capacity and any blockages (partial or full) are removed

Insulation

Whilst heat pumps work at a CoP rating of around 3 and are incredibly efficient, if the property they are fitted in isn’t, much of this efficiency / energy will be lost. 

The homes that work best with heat pumps are those that are adequately insulated. If your home has insulation that is decades old, it might be worth considering an upgrade. This will ensure that the energy / heat the pump produces is kept within your property, in turn, reducing your bills dramatically. 

Radiator Upgrades

Like insulation, if you have old radiators, it’s likely they’re inefficient. New radiators tend to offer around a 50% increase in efficiency compared to old ones which means your air source heat pump won’t need to work as hard to heat up your home. 

And generally, when you upgrade radiators to be used with an air source heat pump, you should buy bigger ones. 

Heat pumps work low and slow, compared to a gas boiler that works in short sharp blasts. Upgrading to newer, bigger and more efficient radiators will allow your heat pump to work at its optimal efficiency level. 

Use our heat pump tool here to get a fixed price on a suitable pump, as well as recommendations on radiator upgrades where necessary. 

Or, if you have any questions you can speak to our heat pump experts via phone, chat or email here. 

Use Smart Controls

Most heating systems nowadays come complete with WiFi compatibility, smart controls and relevant apps. 

Not only are these features designed for convenience (you can adjust your heating remotely and track usage), they’re there to help improve energy efficiency. Using smart controls alongside a relevant app can contribute to helping your air source heat pump work at maximum efficiency. 

What Does Coefficient of Performance (COP) Mean?

Coefficient of Performance (CoP) rating is the most common way to determine a heat pump’s efficiency. The simple calculation for a heat pump’s CoP rating is:

Heat produced (kWh) / Electricity consumed (kWh) = CoP rating

So, 3kWh of heat produced by 1kWh of electricity consumed by an air source heat pump would mean it has a CoP rating of 3. This equates to 300% efficiency.

As a comparison a gas boiler working at 90% efficiency would only produce 0.9kWh of heat, consuming the same 1kWh of energy (gas in this case). This leads to a CoP rating of 0.9.

What Does Seasonal Performance Factor (SPF) Mean?

When measuring the efficiency of air source heat pumps, you’ll see both CoP and SPF (Seasonal Performance Factor) ratings listed. 

CoP focuses on the efficiency of an air source heat pump at any given moment and will depend on the outside temperature. The Seasonal Performance Factor (SPF) takes into account the energy (kWh) consumed by your property on an annual basis, and in turn, what your heating system manages to produce in terms of heat (kWh). 

So, whilst the CoP rating is important when determining how efficient an individual unit is at a certain point in time, the SPF rating of your overall heating system annually is a much more realistic figure.

For example, a 5kW air source heat pump that has a CoP rating of 3, might actually have a terribly low SPF rating if it’s fitted to a property that’s too large. It will have to work overtime to keep up with demand and that will reduce the SPF rating. 

When suggesting a suitable setup and specific ASHP unit, we take all efficiency ratings into account. 

Remove the confusion when picking your air source heat pump using our 2-minute clickable heat pump installation tool here.