Where is it most worthwhile to exceed the requirements of the Energy Saving Ordinance?

Hello,

we are currently planning a solid house, and there is still some financial leeway. Now the question for me is whether it would be possible to improve the energy standard of the house in any direction, compared to the originally planned "just barely" compliance with the Energy Saving Ordinance 2016 requirements. This is not necessarily about return on investment; I assume that in most cases it will be negative anyway. However, it is about where it would make the most sense to "upgrade" the house so that it is not a complete waste of money and maybe also offers a few comfort advantages (e.g. cooler climate in high summer or similar). The common KfW subsidies are unattractive to us, so fulfilling a KfW standard is not the goal.

Conditions planned so far:
- 2 full floors, without a basement
- solid 36.5 Poroton air-filled blocks (condition: the walls should not become thicker if possible)
- central controlled residential ventilation with heat recovery (for comfort reasons)
- gable roof with insulation of the roof instead of the ceiling of the upper floor
- solar system probably rather unfavorable, as roof surfaces are oriented at 22° to the west and east
- heating with air-water heat pump

What would be the "most sensible"?
- Poroton bricks filled with something?
- Better insulation under the floor slab?
- Ground-source heat pump? (the ground has a fairly high groundwater level, is that even possible then?)
- Modulating/power-controlled air-water heat pump?
- Better windows?
- Better insulation of the roof?
- Other suggestions?

Or to ask differently, what would be for you the most sensible mix of the Energy Saving Ordinance and the KfW 55 requirements?

Looking forward to the answers.

Best regards

and there is still some financial leeway.

Don't you need a buffer for earthworks or equipment?

If photovoltaic or solar thermal systems are not worthwhile (we still have the compulsory solar thermal system on the east roof), I would choose an air conditioning system and a patio cover in the wish list, provided there is enough electrical comfort and enough windows installed in the house. Otherwise, I don't think anything will pay off. For savings of €5-10/month, you don't have to invest thousands.

But I'm not an expert at all and therefore look forward to further suggestions.

As long as the feed-in tariff for photovoltaics is still available, it is worth it, even with a North/South roof. Whether the tariff will expire is unclear, but it could happen.

The most sensible investment I see here alongside photovoltaics is investing in good planning of the heat pump and the surface heating: have a room-by-room heating load calculation done and google a lot yourself to avoid mistakes with heat pumps in order to be able to give specifications to the craftsmen. That brings more than the next better energy standard.

Insulate more where it is cheap or where you cannot access it later. Is insulation under the floor slab planned?
Strong imbalances between the heating loads of individual rooms should also be avoided. That means, for example, that the ground floor and upper floor should be insulated similarly well/poorly. With the usual floor plan, this is probably the case.

Sole: look for [Ringgrabenkollektor]

what would be the most sensible combination of the Energy Saving Ordinance and the KfW 55 requirements for you?

None at all. Subsidies are, secondly, a bonus, meaning they are only supposed to cover the additional investments but not overcompensate; and firstly, they are either fully available or not at all. "Almost KfW55" is subsidy-wise like "no KfW55".

we are currently planning a solid house, and there is still some financial leeway.

Don't worry: when planning turns into building, the leeway evaporates effortlessly as if by magic.

- Better insulation of the roof?

I would start here, together with controlled residential ventilation or air conditioning, so that it is nice and cool in the roof during midsummer.

Upgrade to geothermal energy and/or photovoltaics, possibly air conditioning - but first external (intelligent) shading.

"Upgrading" monolithic wall constructions is quite expensive and the added value is not that great anyway.

You could also upgrade the windows to aluminum. Although it has no energetic advantage, it has a qualitative one.