ᐅ Passive House instead of KfW 70 with Heat Pump?

Hello,

Mörtelkännchen schrieb:
...and the plan is a brine/water heat pump...
Just asking, a ground source heat pump costs quite a lot overall, significantly more than, for example, a gas system with solar support for hot water, but it is also a great solution.

KfW 70 and brine heat pumps match quite well. The focus here is on replacing the somewhat higher demand with renewable energy, which is available year-round. The costs for source development (vertical drilling) are quite high. This can be reduced, for example, by using a narrower trench collector or a slinky-type collector (with a high share of self-performance!).
Well-designed brine heat pump systems achieve an annual performance factor of >= 4.5. Possibly complemented by a photovoltaic system. Sometimes a complete energy balance can be achieved annually.
One common heat generator can be used for both heating and hot water.

With gas condensing boilers, the connection costs can be quite high depending on the region. Consumption (kWh/a) is higher. Solar thermal is usually not very economical in single-family homes, but it helps on paper ;-) Solar radiation availability follows an annual and daily cycle, so it is not constantly available throughout the year.

Mörtelkännchen schrieb:
...Would it generally be better invested to consider building a passive house instead of a KFW 70 house? ..

A passive house follows a different concept. Heating energy demand is lowered by very good insulation. The demand for hot water remains unaffected. Heating loads are extremely low. Solar and internal gains intentionally play a major role in the energy balance. Ventilation losses represent a relatively large percentage. The ventilation system becomes significantly more important. Heating load fluctuations are therefore much greater, albeit at a low level. Whether underfloor heating, which is slow to react, is still sensible here should be examined.
For heat generation for heating and hot water, two separate heat generators of smaller capacity are often required.

Reliable values can, as always, only be established after the actual demand (capacity, energy) for heating and hot water has been determined beforehand (basic assessment).

Regardless of the solution considered, careful system planning and sizing is essential in every case.

Best regards.

Hmm, true, I hadn’t even considered the hot water since it’s always the same... Solar gains are naturally difficult to calculate. For example, if you close the roller shutter to avoid glare from the sunlight reflecting on the floor in the living room, the situation changes again.

Mörtelkännchen schrieb:
Hmm, that’s true, I didn’t even consider the hot water since it’s always the same...

Exactly, thermal insulation does not help with hot water demand at all!

Mörtelkännchen schrieb:
...Solar gains are, of course, difficult to estimate; for example, if you close the blinds to avoid glare from sunlight reflecting off the floor in the living room, the situation changes again

During the cold season and transitional periods, solar gains in a passive house are quite beneficial, usable, and even essential. However, in the hot season, these gains must be significantly reduced through appropriate measures. ;-) Cooling load calculation!

Best regards.