Heat Pump COP, SCOP & SPF Meaning

Below we’ll explain the meaning of efficiency ratings for air source heat pumps including the likes of: COP, SCOP and SPF. 

This is a 10-minute read. So, if you’re short on time, you can bookmark this page for later and read our quick overview below. 

Overview: Our Heat Pump COP, SCOP & SPF Guide 

A common indicator of a heat pump’s efficiency is COP (Coefficient of Performance). This highlights a pump’s efficiency at a single point in time, based on a specific outdoor temperature and pump flow temperature. 

However, a much better measure of expected efficiency (and therefore, energy bill savings) is Seasonal COP (SCOP). This measures the COP rating throughout the entire heating season and gives an average. 

Remember, this rating will change based on the flow temperature of your heat pump. The higher the flow temperature? The less efficient your heat pump will be and therefore, the lower the COP / SCOP rating. 

With any efficiency rating, the two main variables are always flow temperature and outdoor temperature. 

High outdoor temperatures help with efficiency, as does a low flow temperature. 

An average heat pump should operate with a SCOP of 3 or higher when set to a 50°C flow temperature. However, plenty of heat pumps exceed this rating, such as the Ideal Logic Air 8kW which operates at 3.96 (it's 396% efficient).

We install some of the most efficient air source heat pumps available in the UK from leading brands such as Vaillant, Ideal Heating, Viessmann, Samsung and more… 

Get prices on-screen for the most efficient heat pumps using our clickable tool here. 

What Does Heat Pump COP Mean?

A heat pump's efficiency rating is generally listed as a COP (Coefficient of Performance) value. Put simply, COP is how much heat a pump produces for every unit of electricity it consumes. 

For example, if a heat pump has a COP of 3, it would generate 3kWh of heat for every 1kWh of energy it consumes. That means this unit would be 300% efficient. 

That’s a big boost compared to a gas boiler, whereby even an A-rated unit would only be 94% efficient; 0.94kWh of heat produced for every 1kWh of gas consumed. 

The COP rating of heat pumps is based on a set of variables at a single point of time. For instance, a heat pump working at a flow temperature of 50°C, with an outside temperature of 15°C.

What Factors Affect a Heat Pump’s COP?

A heat pump’s COP is affected by a handful of variables, the most prominent being: 

• Outdoor temperature
• The heat pump’s flow temperature

When the temperature outside drops, your air source heat pump will need to work harder, and that’s going to drop its COP rating considerably. 

A pump that was working at a COP of 3 when outdoor temperature was 18°C, could easily drop to a COP of 2 when outdoor temperature is down at 12°C.

And this is simply down to the flow temperature your heat pump needs to work at to meet heat demand. The colder the temperature, the higher the flow temperature of your heat pump needs to be to maintain your central heating’s temperature.

As an example, let's look at the Ideal Logic Air, one of the most efficient heat pumps available in the UK.

The Ideal Logic Air 4kW unit operates with an extremely high COP rating of 5.34 (534% efficient) when running at 35°C. So, it uses 1kWh of electricity to produce 5.34kWh of heat. 

Bump the flow temperature on your heat pump to 55°C? 

You'll see this COP rating drop considerably to 3 (300% efficient); it uses 1kWh of electricity to produce 3kWh of heat. 

How Does COP Differ To SCOP?

Heat pump manufacturers generally list efficiency values for both COP and SCOP (Seasonal Coefficient of Performance). Of the two, SCOP is generally the more accurate measure. 

Whilst COP measures a singular point in time with fixed inputs (e.g. flow temperature of 35°C with an outdoor temperature of 15°C), SCOP measures a whole season of heating performance. 

This means it offers a clearer representation of the potential efficiency of your heat pump, as it’s taking averages as temperature fluctuates throughout the year.

However, like COP ratings, SCOP ratings are affected dramatically by flow temperature.

If we use the Ideal Logic Air again as an example, you can expect the following SCOP ratings based on your heat pump's flow temperature:

Put simply, with both COP and SCOP, the lower the flow temperature of your air source heat pump, the higher the rating and therefore, the higher the efficiency. 

What is The Average COP / SCOP For A Heat Pump?

The innovation of heat pumps means that almost every year, the average COP / SCOP rating improves. 

When looking at COP / SCOP efficiency ratings offered up by manufacturers, you’ll want to note the flow temperature. As we mentioned above, the lower the flow temperature, the higher the COP / SCOP / efficiency of a heat pump. So, make sure you compare like-for-like flow temperatures. 

We’d expect a heat pump from a leading brand to be in excess of 3 COP / SCOP, even when operating at a flow temperature of 50°C. 

Here are a few examples of SCOP ratings from top heat pump manufacturers: 

If you’re considering buying an air source heat pump with a SCOP of lower than 3 when operating at 50°C flow temperature, choose one of the above pumps instead!

We only fit heat pumps with a SCOP of above 3 when operating at a flow temperature of 50°C. To get fixed prices on-screen for these units, use our clickable heat pump form here. 

Which Heat Pump Has The Highest COP?

Of the air source heat pumps that we currently install, the Ideal Logic Air is the most efficient, offering the highest COP / SCOP ratings. 

Below are the COP / SCOP ratings for the 8kW Ideal Logic Air: 

Full specifications of the Logic Air can be found on Ideal’s site here. 

To get prices on air source heat pumps with a high SCOP rating such as the Ideal Logic Air, use our clickable heat pump installation form located here. 

What is SPF?

Seasonal Performance Factor (SPF), is very similar to Seasonal COP. Effectively, it measures COP across the full heating season, rather than at a specific point in time. 

Measuring air source heat pump efficiency based on SPF / SCOP is much more accurate than using COP…

And that’s it for our guide covering heat pump efficiency ratings. 

For further reading, check out our guide covering heat pump efficiency here. 

Or, go ahead and get prices on the most efficient units by using our clickable heat pump quote tool here.