Heat pump capacity and buffer tank size(s) for new build single-family house

Hello everyone,

we would like to order our components for the heating system as soon as possible.
The following data is the basis:
- New build single-family house according to legal standards
- heated living area: 193m² ([Floor plans attached])
- planned heat pump: ground source heat pump Bosch CS 7800iLW 8 F 8kW
- planned buffer storage tank: Stora WH 370 LP1B
- drilling depth will be determined according to the system
- designed for a household of 4 people

Questions: do you consider the 8kW ground source heat pump sufficient? Do you consider the buffer storage tank with 350L content sufficient? Is a second buffer tank for the heating water not necessary?

Thank you very much and best regards

Remove the buffer if one is planned. What you mean is the hot water storage tank. Have a room-by-room heating load calculation done, design for a maximum flow temperature of 32 degrees. Then adjust the heat pump’s capacity to the heating load with a tendency to choose the smaller heat pump. Afterwards, have the required drilling meters determined, use improved grouting material. Ideally, only one borehole and not several – this can also go deeper than 100m.

Do without / free / disobey / disconnect the individual room control.

Congratulations on the cost-efficient heat pump system.

Don't you need a second buffer for the heating water?

That used to be done when the oil/gas burner ran at full power for a while and was then turned off again. The thermostat on the radiator then controlled how much of the water circulated through the heating system. Nowadays, the flow temperature is controlled by an outdoor temperature sensor, and the heat pump modulates accordingly. Smaller interruptions are buffered by the screed. The thermostats on the walls react far too late to be really useful. Accordingly, I have most of the heating circuits set to manual open. It's better anyway because there are people in this household who fiddle with them and then again after 10 minutes...

The critical point has already been mentioned, don't let your heating be designed in the cheap version at 35 degrees.

Hello everyone,

thank you for your responses, that means we are on a good path.
And how do you set different temperatures for the rooms if you don’t have a thermostat? Manually open/close?

Best regards

You won't achieve gigantic temperature differences in a new building anyway. A hydraulic balancing is done, i.e., via the flow rate and the control at the heat pump, the rooms are brought once to the desired temperature level and the setting is kept that way.

Hello everyone,

thanks for your answers, that means we are on a good path.
And how do you set different temperatures for the rooms if you don't have a thermostat? Manually open/close?


Best regards

What does the path look like then?
Instead of room-specific heating load calculations, I only see floor plans. ;-)