FAQ - Questions about technology

Solar thermal energy is an option worth considering if it is to be used both for warm water and as a heating aid in a new building.

A retrofitted solar thermal plant for the warm water supply, however, affects only a small part of energy consumption within a household. In this case, such a plant pays itself off either very slowly or not at all. With a photovoltaic plant on the other hand, the high procurement costs are offset by the prospect of a considerable profit. In short: unlike a solar thermal plant, a photovoltaic plant will have completely paid itself off in eleven to thirteen years due to the state-guaranteed feed-in remuneration and will then yield a definite foreseeable profit.

Therefore potentially “valuable” roof surfaces facing south should preferably be used for highly-economic PV plants than for solar thermal plants especially since the latter does not really essentially contribute to a reduction in CO₂ because of its restriction to a small part of the daily energy requirements.