ᐅ Solar for hot water and heating, or is photovoltaic better for electricity?

Pädda schrieb:
Thank you very much for your support! This is how I will proceed.
If, in the end, solar thermal systems must be installed on the roof, they will only be as large as necessary to meet the energy saving regulations. Would such a small solar thermal system then be used to support the heating system, for hot water, or for both? Are there any recommendations?

It’s primarily a cost issue. What is the cost difference between option 1 and option 2? And what heating support can realistically be expected in winter? Are any additional expenses justified?
This depends on the location, as well as the planned tilt and orientation of the solar thermal system....

Have the energy saving regulation requirements become that strict nowadays?

An independent energy consultant should be able to provide a solution. As far as I know, if you use gas, solar thermal systems are still uneconomical for single-family homes.

From an economic standpoint, a heating system is never profitable. Solar thermal systems are not either. Controlled mechanical ventilation is also not profitable. This is not the aim of the energy saving regulations, which are not meant as an economic tool but to save energy.
Alternative measures to avoid using solar thermal plus gas would be:
- Reducing transmission losses by 15% (--> KfW 55 standard; higher investment costs for a better building envelope tend to be more expensive than a small solar thermal system; uneconomical like all other measures, costs for insulation versus energy saved)
- Possibly controlled mechanical ventilation, if at least 50% of the heat demand is supplied from waste heat (--> controlled mechanical ventilation tends to be more expensive than a small solar thermal system; equally uneconomical, but provides increased comfort)

The most important factor is still insulation.
In 2014, I paid €258,000 for a turnkey passive house with 176 sqm (1,895 sq ft). It had upscale finishes. A standard gas boiler combined with mechanical ventilation with heat recovery saved me around €21,000 compared to expensive heat pumps and similar systems. The energy demand ranges between 3,200 and 5,000 kWh. Two people live in the house and shower daily. There are few windows on the north side. The average room temperature is 22.5°C (72.5°F).
Although various heating technologies receive subsidies, they are not necessarily economical. Monthly costs are about €80 for electricity and €32 for gas. Annual maintenance for the gas boiler is €105.
There will still be people who spend €30,000 to €35,000 on a heating system and then wonder about their electricity bills.
With the savings of approximately €21,000, I can heat for a very long time—I don’t care about subsidy programs.