Planning / Energy Consulting

Hi,

hope you can help me and that I am writing in the right category. We are planning to build a house and I am somewhat overwhelmed. I would like to keep the additional costs (heating, electricity, etc.) low, but still not spend too much money unnecessarily. I also find renewable resources good and therefore have my questions.

Data: - Kfw55 house with 42.5cm aerated concrete masonry. - The house has about 133sqm and 126sqm according to the Wohnflächenverordnung. - 4 people will live in the house later. - It has decentralized heat recovery with ceramic core. - The windows are triple-glazed with a U-value of 0.6 - Underfloor heating throughout the entire house. - Plastic roller shutters throughout the entire house - 24cm roof insulation WLG 035 - 5 cm slab insulation Styrodur C

Now we face several questions, hope you can help us.

1. We wanted a brine/water heat pump (Vaillant flexocompact-exclusive-vwf-118-4) with 2 drillings, but maybe an air/water heat pump (Rotex HPSU 508) is enough after all

2. A photovoltaic system with storage is planned. How many kWp should it have?

3. Is a water-bearing fireplace for the underfloor heating worthwhile with/without chimney?

4. Is solar thermal still worthwhile?

5. We wanted to install a 2kW small wind turbine, is that sensible?

6. The roof pitch is 45°, should we adjust it to 35° or 40°?

Thank you very much for your help. Best regards David

1. We also have the brine-water heat pump; however, 58-4 for 190 sqm living space. - the 118-4 is FAR too big for 130 sqm - the 58-4 is enough (I say this even though I don't know your construction project in detail); air-water heat pump is also sufficient - a fireplace inside the house is also enough. The question is rather what you want. I would base the choice between air-water heat pump or brine-water heat pump on the specific offers. For 130 sqm KFW55, the difference in energy costs is in the 10 to 20 € range per month. 2. As much as the wallet allows - or not at all. It is a nice gimmick but has a moderate return (if bought expensively, possibly none at all); but you usually don’t burn money with it either 3. No 4. No 5. No 6. I would have this determined by the house planner, not by the renewable energies

Just as info: For my KfW55 house construction planning with 141m², the heating load calculation is just finished: 3.6kW + hot water = 4kW. 1.6km underfloor heating with a supply temperature of 27°C at -12°C outside. It will probably be 1 deep borehole.