ᐅ Solar Thermal vs. Photovoltaics

Good morning, we have some questions. We are building a semi-detached house with a Dimplex Law9 IMR. The conduit for photovoltaic systems has been planned.

Would it be more practical to prepare for solar thermal systems in a semi-detached house instead? We have limited available roof space (two windows are installed on the roof).

We called Dimplex yesterday, but their answer was somewhat vague and seemed to favor photovoltaic systems (I had forgotten to mention the windows and the semi-detached house). Their reasoning was that the heat pump runs efficiently in summer and you mostly need the electricity then, which is generated by photovoltaics. In winter, a photovoltaic system is also more practical because it is more efficient.

What is your opinion?

Photovoltaics make more sense than solar thermal systems.

As long as the roof is reasonably suitable, it’s possible to install a photovoltaic system.

Solar thermal systems produce "only" hot water. In summer, they generate a lot—even more than you need; in winter, rather little. Photovoltaic systems produce "only" electricity. In summer, a lot—so you can use it or sell it. In winter, rather little.

Photovoltaics offer you more.

nordanney schrieb:

Solar panels only generate electricity. In summer, there’s plenty – you can use it or sell it. In winter, not so much.

It’s not that bad in winter either. As of today, we have produced 368 kWh this December despite several gloomy foggy days and not even having a south-facing roof. Of course, this doesn’t make the system profitable yet, but it’s still better than (almost) nothing. On clear days, we have repeatedly generated more than 25 kWh per day (28 kWp, east/west/south-west roof).

PS: If you have excess electricity, you can use it to heat water; the other way around is more difficult at home 😉

Fuchur schrieb:

It’s not that bad even in winter.

I know – but this way it’s easier to explain more vividly 😉 😎