Energy Saving Ordinance 2016 or KFW 55 for bungalow with air-water heat pump & controlled residential ventilation, optional photovoltaic

Fundamentally, the planner must point out the circumstance of the loss of value, because in about 1-2 years the Passive House standard applies in the Energy Saving Ordinance.

The loss of value is probably marginal; almost no buyer is familiar with it and even fewer base their decision on nuances in insulation. For the operating costs, it is more relevant in practice whether the heating system was properly planned and operated. The result can then be seen – also when selling – in the consumption certificate, where some places are better than other Passive Houses.

The question is only how the house is proven, i.e., how good the building envelope really is. So without a high primary energy factor as with electricity or even with photovoltaics.

The H't value provides information about the quality of the building envelope.

Porous concrete is at least according to the offer

: I didn't find it quickly from Vaillant, but the Nibe F730 has exactly this exhaust air heat pump, why should it be worse than outdoor air? The system is the same

You make it easiest for everyone involved if you simply internalize as given "no exhaust air heat pump in a non-passive house."

I will sit down with customer service for a consultation.

Exhaust air heat pumps with central exhaust air and decentralized supply air
This solution uses the system-induced slight negative pressure in the apartment. It ensures that fresh air flows in through exterior wall vents in the supply air areas. The room-warm exhaust air is directed from sensitive areas such as the kitchen, bathroom, or guest toilet to the heat pump through ventilation pipes. Before being discharged outside through a roof hood or ventilation wall grilles, most of the contained heat energy is extracted. The exhaust air thus serves as a heat source for the integrated heat pump to generate hot water for heating and domestic water. Usually, these systems are designed as compact units with an integrated domestic hot water storage tank.

Exhaust air heat pumps with central exhaust air and central supply air
These heat pumps operate on the same principle as the previous system, but the supply air is preheated via the heat pump and directed through ventilation pipes into supply air areas such as bedrooms, children's rooms, or living rooms.

Air/water heat pump with crossflow heat exchanger <-- maybe this model here!?
Here, the exhaust air, after transferring most of its energy to the supply air via a cross-counterflow heat exchanger, is discharged and disposed of outside. Depending on the heat demand, it still flows over the surface of the air/water heat pump evaporator. There it transfers additional residual heat to the heat pump's refrigerant cycle. If additional energy is needed for heating or domestic hot water preparation, it is obtained from the outside air supplied additionally to the heat pump.

In addition, I will look at the consumption values from the online database, although unfortunately they have only been recorded since 2018/2019.

Ultimately, the consensus seems to be: if heat pump, then better insulation as well. But without precise calculation, it probably remains a rough estimate.

Best regards,
Michael

Ultimately, the consensus seems to be that if you have a heat pump, then you also need better insulation

Better insulation increases the efficiency of the heat pump, but at some point insulation also becomes uneconomical. There are also plenty of people who heat their old buildings economically with a heat pump. Energy Saving Ordinance houses are already reasonably well insulated. Controlled residential ventilation in addition, improving insulation here and there (with or without KFW) and it will work. More important is the planning of the surface heating and the hydraulics overall, as well as making sure not to install any nonsense.

It always depends on the framework conditions: The cost factor for timber frame construction without a basement is marginal. Solid with brick without ETICS but with a basement is a completely different matter to get from the Energy Saving Ordinance 2016 to KFW55.

Good, I cannot judge the timber frame part, we only have a standard double-shell masonry. That was enough for KFW55. The consideration is very individual, that's true. For us in 2016, the KFW loans had such good conditions that we saved a lot on interest, and together with the 5000€ the whole thing pays off. However, because of only about 10% equity, we did not have the best interest conditions.

@boxandroof

Precisely because a layperson cannot assess the depreciation, a planner can possibly also be held liable. The running costs are directly related to this. A heat pump is only doing well at the moment because the primary energy factor has been raised accordingly by politics. Which does not change the cost per kWh.

The Energy Saving Ordinance is not being replaced by the Building Energy Act after EnEV2019 for no reason.

If it were actually a passive house from 2020/21, we would possibly only speak of an electric heating coil in the ventilation system with heat recovery.

Better insulation also does not increase the efficiency of a heat pump, which is generally equally poor in air-source heat pumps. An annual performance factor of at least 4.0 is an illusion. VDI 4650 is not a practical assessment, which would also be pointless, as then every manufacturer could calculate an annual performance factor as they please.

In addition to the higher operating costs, there is also the short lifespan of the air-source heat pump; the necessary reinvestments go directly into the ROI. (assuming normal hot gas temperatures)