Solar and heat pumps: A match made in heaven?

‍As many householders know, a heat pump works by using energy from the outside air or the ground as its “fuel” to produce heating and hot water for our homes or businesses.

It converts this “fuel” into renewable energy using electricity. An air source heat pump can produce 3KW or more energy from 1KW of electricity, and a ground source heat pump can produce 4KW or more.

Householders also know that solar PV panels generate electricity by using the sun’s energy. So, we might naturally assume (or are sometimes told) that the electricity generated by solar PV can run our heat pumps.

Free heating! It sounds like the perfect combination.

However, the fly in the ointment is that PV panels produce a relatively small amount of electricity in winter when we need our heating and hot water most. And furthermore, that electricity is generated during restricted daylight hours, when typically we are running our heat pump system in the mornings and evenings.

As you can see from the graph above, the times of the year you need your heating most don’t match with the times that solar PV works best.  

Solar PV panels, therefore, have less impact on lowering costs for running a heat pump in the winter months than we might think. And during the summer we won’t be using the heat pump much, other than to heat hot water - although with the correct timings this can give you near-free hot water for 3-4 months of the year.

Don’t get us wrong, both heat pumps and Solar PV can each provide great environmental and financial benefits in their own right – it’s just that together they may not be such a match-made-in-heaven as we might assume.