Having a solar heated loop for radiated heating in the floor is definitely a setup I want to get going.
Wouldn’t places with good conditions for solar heating generally not need the underfloor heating for the season when the solar heating is most effective?
This has been my impression, and why solar heating is most useful for heating water.
The question is: is it efficient enough during the cold season? Cyprus, situated in the middle of the Mediterranean heat reservoir and with plenty of daylight during the off season seems to be well situated.
As for the need: I’m from up north, our houses are built to keep heat inside as that is most positive for our energy consumption. In the south, houses try to limit the need for cooling. The effect of which became very clear to me when I went to the Mediterranean in November. Heating? Yea please.
Pretty much all houses in Greece have this and no, it is only good for the summer or sunny days. But still it is a no brainer, unlimited free hot water during the summer and limited free hot water during most days.
The tricky part is calculating whether it was sunny enough(during the winter) to produce enough hot water for your shower or if you need to turn on the electric water heater.
Some greeks pre-emptively turn on the electric heater for 15-30 mins, other more financially stressed greeks prefer to gamble.
So I actually have experience with these in the north of Sweden - they are definitely more efficient in summer, but do provide some amount of hot water as well in winter on days with clear sky (of which there are few).
On the topic of using this for heating in the Mediterranean - I don’t think that’s where you want to invest, installing underfloor heating in one of those houses. That will cost some serious money. It’s probably wiser to spend it making the home less prone to get cold/hot using insulation in that case. I will admit to being out of my depth when it comes to optimizing buildings for hot climates though
