Determine collector area

If you know your daily heat demand you can enter it manually (e.g. daily heat demand = heating load * 24 h).
The daily heat demand must be entered in kWh per day!

If you do not know your daily heat demand, you can calculate it approximately with our calculation program:

Approximate calculation of the daily heat demand based on heating and hot water demand

 kWh per day

 kWh per day


The approximate calculation of the daily heat demand is for information purposes only and does not replace the heating load calculation according to standard DIN EN 12831, which is required by law for new buildings.
The daily heat demand depends on the type of building (standard EFH 24 h), average room temperature 20°C, outdoor temperature on the coldest day of the year (default -16°C or depending on the location).
Calculations of solar systems are a very complex topic and depend on very different factors. Therefore, this calculation is only an information and planning help. It does not replace the technical planning and the advice of the installer on site. The actual yield and consumption quantities may differ from the example shown depending on user behavior, wood quality and building data.

Collector area for domestic hot water

To calculate the size of the solar system for DHW heating, the collector area should be calculated depending to the number of persons or to the volume of the possibly already existing solar storage tank. At least 1 m² collector area should be installed per each person for a normal demand (approx. 50 L/person). To reach a higher solar coverage, 1.5 m²/person is also possible. If the DHW tank already exists, 1 m² is usually installed for every 50 liters of DHW tank volume.