ᐅ Biogas as an Alternative to Solar Thermal Systems in New Construction

This year, we are building a new house with approximately 170 m² (1830 sq ft) of living space. Natural gas is planned as the energy source. According to the Renewable Heating Act, at least 15% of the energy must come from renewable sources using solar thermal systems.

170 m² (1830 sq ft) * 0.04 m² (solar collector area) / m² (living space) = 6.8 m² (73 sq ft) solar collector area, which means at least 3 panels.

Now I have read that by using biogas (at least 30%), the solar thermal requirement can be replaced.

Is that correct? Has anyone had any experience with this?

What size should the domestic hot water storage tank be for a household of four (2 adults, 2 children)?

Thank you.

Do you mean district heating from a biogas plant? Do you already have district heating available at your property boundary?

Alternatively, heat pumps can also be installed.

or simply more insulation

Hello, thanks for the answers. By biogas, I meant certified gas with at least 30% biogas content, which also costs more (probably about 1/3 more). The law mentions something about combined heat and power.

According to the architect, adding more insulation does not seem to be that simple.

We have now decided on a gas condensing boiler and a 1000-liter (264-gallon) energy buffer tank, supplied by the boiler and the solar system (4 panels with a total area of 10m² (108ft²)). Domestic hot water is stored in a 160-liter (42-gallon) hot water buffer tank.