As for planning/design of energy standard and heating concept

Hello everyone,

for days (or rather weeks) now I have been dealing with the topic of house construction.
First of all, it will be a semi-detached house and the architecture is being done by an acquaintance who is an architect. He is taking care of all the work necessary to submit the plan. Heating concept, ventilation concept, etc. are not included here.

The plot has a slight slope, which is why we are planning a 50 m^2 granny flat on the ground floor, and the area behind the flat, which adjoins the earth, is to become a basement for heating systems, etc.

In total, the house will have about 250 m² gross floor area and a roof pitch of 45 degrees.

I have also already read a lot here in the forum, which has helped me a lot, but I think that with the topic of house construction, each issue requires its own discussion ;)

My questions are certainly the absolute classics:

[*]House construction according to the Energy Saving Ordinance 2016 or going for KFW55?
I am currently not sure whether it will be a house according to the Energy Saving Ordinance 2016 or KFW55.
Ultimately, this is a question of economic efficiency. But how can I find out exactly?
Do I go to an energy consultant with my house plans, who will then calculate this for me at the end of the day?
What costs can one expect for such an assessment from an energy consultant?

Currently, I plan to build with Poroton T9 36.5. As far as I know, it will be tight anyway for KFW55 with these bricks, since the U-value is about 0.23?

[*]Ventilation system
From when is a ventilation system actually mandatory?

[*]KFW subsidies
I do not intend to take out a KFW loan. Can I still take advantage of individual KFW subsidies? Can I apply for individual subsidies myself, or does every subsidy really have to go through the bank?

As far as I know, I have to apply for all subsidies before implementation. So you cannot build first and apply later, right?

[*]How to heat?
I want to design my heating system primarily economically. It is generally not the main goal to be as green or self-sufficient as possible. It is simply to have the “most economical” system from today’s perspective with a view over 15 years (the assumption for this would be today’s prices for all necessary resources). There is a gas connection laid to the property. Currently, the new development area is advertising for fuel cells (up to 10,000 € subsidy). Are there any experiences here? The system sounds great in theory. High efficiency, etc.

After reading a lot here in the forum, I have come to the conclusion that an air heat pump with a small photovoltaic system is currently probably the most economical?

This preoccupies me a lot, as I am desperately trying to find the most suitable energy concept for my project and do not know the best way to proceed. For me, the standard according to the Energy Saving Ordinance 2016 is already not bad. Maybe you can save yourself all the effort and simply build accordingly with a gas condensing boiler?

Regards!

Have a look here:



Should be very interesting for you.

I am very concerned because I am desperately trying to find the most suitable energy concept for my project and do not know how to proceed best. For me, the standard according to the Energy Saving Ordinance 2016 is already not bad. Maybe you can save yourself the whole effort and just build according to that with a gas condensing boiler?

In the end, it depends on what prices you get for which type of heating. With heat pumps, more own work is possible; otherwise, in my opinion, prices for heat pumps are often set too high. Heat pumps are more efficient the better the house is insulated and the larger the well-planned heating surfaces are, but that does not mean that a heat pump does not make sense even with the Energy Saving Ordinance.

Where insulation is cheap, I would not save.

The only thing that can almost be said across the board is that photovoltaic is almost always worthwhile with the current subsidies if you do not wait too long.

Energy Saving Ordinance standard. That’s enough. Gas heating, with heat meters for the apartment and the granny flat. To be able to bill fairly. The renewable share is ensured by a controlled residential ventilation system with heat recovery, which also makes the granny flat mold-proof in case the tenant ventilates poorly. Advertise the granny flat accordingly, and charge 1,- more per sqm rent for fresh air and less heating. I have rented for decades, this is a different level, not sophisticated counts here but simple rugged reliable. And for your residential share, that is not wrong either.

Oh, is a part being rented out?

Decentralized ventilation for the rental apartment, test listening so that the tenants do not turn it off if it annoys them.

Separate or shared gas boiler for heating the rental apartment. A heat pump sensibly has low output and no buffer tank, which does not fit tenant behavior and room thermostats. Domestic hot water quality must be 100% and hot water always available. With a heat pump this is indeed feasible (e.g. high hot water temperature in the storage tank + solar-compatible instant water heater at the tank outlet or with fresh water station + instant water heater), but it would be less economical and more complex. And the local heating engineer should be able to repair the tenant’s heating.

One can consider a heat pump in their own residential unit. Also calculate in terms of incidental costs for the landlord with separate heating.

Ventilation instead of solar thermal works for the Energy Saving Ordinance only with a good energy consultant, possibly not even with the minimum insulation.

Can you still get KFW funding twice today for 2 residential units (granny flat plus own) ?

If yes, you should check that again......We did it but not because of the "great" conditions but to be more flexible.....with us, you could still make special repayments without limit and the loan ends after 10 years and then our monthly burden finally decreases significantly..

Think carefully about the 36.5 if you have tenants, you should actually take something filled! The tenant will not want to hear the noises you make downstairs.......and if you take something filled you are almost back at KFW 55. You have to apply for the funding beforehand.....and also be careful with the impact sound insulation.....

Take gas. See another thread and comment by BoxandProof.

I would only do decentralized in my own bathroom because of the comfort; otherwise, the things are too loud for me to run constantly in living spaces. But maybe there are better devices nowadays.