ᐅ Poroto T9 without external thermal insulation composite system (ETICS) and without solar thermal system

Hello everyone,

I spoke with a company today, and they said that with a single-layer masonry wall made of poroton (T9) and without solar (domestic hot water), you cannot get a building permit / planning permission. Is that correct? I was under the impression that in such a case, the building just needs to improve its insulation by 15%. So, what is actually correct?

Just take a look at the energy saving regulations. They contain all the information on what you need to do and what is required.

It depends on the heating system.
I assume you just want a gas boiler... but that's no longer allowed; it has to be renewable now, so with solar.
Or you can choose a heat pump, then you don’t need solar. That doesn't make much sense though... When it’s cold outside and the solar doesn’t produce any energy, your heat pump has to work harder... It also has a low efficiency because it’s cold.
Of course, you can also do geothermal drilling or use collector panels... All pretty expensive, and whether it works depends on the professionalism of your heating specialist.

By the way, this is what I chose for my new build:
Gas plus two solar collectors for hot water preparation.
Decentralized ventilation system
24cm (9.4 inches) Poroton brick + 12cm (4.7 inches) external thermal insulation composite system (ETICS).
24cm (9.4 inches) insulation between roof rafters
5cm (2 inches) perimeter insulation under the slab
= KfW 55 standard! ;-)

Solar power used only for domestic hot water makes little sense in my opinion. It is usually installed just to meet the legal minimum requirements. The savings are likely minimal when you consider the high initial costs... If I have no other option, I will probably go for solar to support both domestic hot water and space heating.

Why should that make little sense?
Whether you reduce the load on the gas boiler by heating the water tank through the solar system,
or reduce the load on the gas boiler by partially heating the water tank and partially the heating circuit through the solar system...
It’s essentially the same.
If you do this, please plan for twice as many solar panels as you would need just for domestic hot water support, otherwise it really won’t make much sense 😉

So, using T9 insulation is certainly more challenging, but not entirely impossible. The wall thickness will probably need to be around 42.5cm (17 inches) or more.

@Nutshell
Of course, gas heating without solar is also possible; you just need to implement compensating measures (about 15% better insulation). I am building with gas heating without solar myself and still achieve KFW70.