How efficient is an ASHP?

Air source heat pumps are incredibly efficient, but getting the system design right is crucial.

The minimum efficiency for an MCS-compliant installation is 280%. But the national average? That’s around 340%. A skilled installer, using top-quality design practices, can push that up to an impressive 400% or even 500%.

These efficiency figures are annual averages, meaning they account for the fact that heat pumps perform better in warmer weather and less efficiently when it’s cold. This efficiency is often measured as SCOP—Seasonal Coefficient of Performance. For example, SCOP 3 is 300%, and SCOP 5 is 500%.

Now, let’s compare this to traditional fossil fuel boilers. They typically operate at around 80 to 95% efficiency, so heat pumps are already looking pretty great.

You might be thinking, ‘But electricity is more expensive than gas,’ and you’re right. However, when you factor in the efficiency, a heat pump running at a SCOP of 3.5 can cost roughly the same as gas and even be a little cheaper than oil.

The real game-changer? By using time-of-use tariffs, solar PV, and battery storage, you could see significant savings.

And here’s the big environmental takeaway: As of today, the carbon intensity of the electrical grid is similar to burning gas. But thanks to the high efficiency of heat pumps, you can reduce your carbon emissions by around 75%, making a real difference for the planet.