Thus the solar panels. So long as the installation proves to make financial sense, the PV production offsets the heat pump efficiency, even in winter months.
The point is that custom solar/geothermal installs seem neat and efficient —- waste not, want not — but probably have a hard time competing with the economies of scale and low maintenance of PV panels and air source heat pumps.
Additionally, winter months are usually the cloudy ones. It's not very uncommon to have just a couple of sunny days per month in European winters, driving down solar gains even if there's no snow cover.
In climates where you will have a bed of snow during the winter months, your optimum tilt angle for a fixed solar panel is something like 30° off of vertical or steeper. I find that on mine the snow falls off since it is a south facing, steep, dark surface.
You engineer to make sure you have enough energy captured each month to meet that months needs. That might lead you to a tilting mount, or just a fixed angle and having surplus energy most months.
In my case, panels were much more expensive when I designed my system, I initially roof mounted them, but when replacing the roof under them I moved them to a pole and went with a tilting mount and manually move the panels twice a year. My load is much higher in the summer, but I still need some power in the winter. And northern winters can be cloudy a lot and have limited sun even on a clear day. At my location there is about a factor of 5 difference in solar energy per square meter per month. So you design for each month and then pick a solution that is best. In my case the summer load is so high that even though I get 5 times the energy, it is still the driving force on sizing the system.
During summer months the production mostly covers and partly exceeds their use, but the sell price is so much lower that it doesn't even begin to pay for the rest of the year. But that of course then relates to the installed capacity.
https://www.pv-magazine.com/2020/03/18/heating-solar-panels-...
If the commenter’s house doesn’t have gas, then it doesn’t seem to make sense to install it, and the price differential in the US isn’t as great as in the UK (how’s that Brexit thing working out?).
I don’t think this is true in many areas. In our area, during the summer the neighborhood is running A/C when the sun is at its peak. During the winter, heating. Also the transport loss from a power station is nothing to sneeze at - my understanding is that locally produced power often just results in reduced demand on the larger grid.
Here in the Sierra foothills, it's been a blazing hot summer. About 90% of our PV generation powered our home air conditioning. We shipped very little energy to the grid on hot days. And it was awesome to have a comfortable environment without sucking grid power on the days when it hit 113°F.
Obviously in many parts of the world, market distortion means the buy price and sell price for electricity is very different, and in that case a heat pump might make sense to combine with PV.