ᐅ Building a Monolithic KfW55 Home with a Basement – A Practical Approach!
Created on: 25 Aug 2017 13:23
Z
Zaba12
Hello everyone,
I already feel a bit sorry for asking this question, as it has been indirectly discussed multiple times here in the forum. I am not concerned with whether KfW 55 is worthwhile or not; I have moved past that with the idea of a controlled mechanical ventilation system.
Originally, I did not want to build to the KfW 55 standard because of the basement. However, since we plan to build from the start with a controlled mechanical ventilation system, a heat pump is mandatory, and I am considering a photovoltaic system (without battery storage) due to owning an electric car, our architect mentioned that aiming for KfW 55 as a building standard would make sense (especially as the south-facing orientation is ideal).
We also plan to include a small fireplace (similar to a Plewa Classic).
Since we still have at least four months before consulting an energy advisor, I would like to ask the following question.
What do you think we would need in addition to meet the KfW 55 requirements effectively?
The draft plan currently shows a 36 cm (14 inch) masonry wall. Would we have to increase this to 42 cm (16.5 inch)? Or would triple-glazed windows suffice? Does the basement need to be heated? It is not intended as a living space, but it should be comfortable to spend time in.
Has anyone here already built a monolithic house with a basement to the KfW 55 standard? Surely, someone must have?
I already feel a bit sorry for asking this question, as it has been indirectly discussed multiple times here in the forum. I am not concerned with whether KfW 55 is worthwhile or not; I have moved past that with the idea of a controlled mechanical ventilation system.
Originally, I did not want to build to the KfW 55 standard because of the basement. However, since we plan to build from the start with a controlled mechanical ventilation system, a heat pump is mandatory, and I am considering a photovoltaic system (without battery storage) due to owning an electric car, our architect mentioned that aiming for KfW 55 as a building standard would make sense (especially as the south-facing orientation is ideal).
We also plan to include a small fireplace (similar to a Plewa Classic).
Since we still have at least four months before consulting an energy advisor, I would like to ask the following question.
What do you think we would need in addition to meet the KfW 55 requirements effectively?
The draft plan currently shows a 36 cm (14 inch) masonry wall. Would we have to increase this to 42 cm (16.5 inch)? Or would triple-glazed windows suffice? Does the basement need to be heated? It is not intended as a living space, but it should be comfortable to spend time in.
Has anyone here already built a monolithic house with a basement to the KfW 55 standard? Surely, someone must have?
Apart from the fact that the land survey has not yet been completed and the plot is not fully developed, there is the issue of funding. The energy consultant will only take action once payment is secured. It may sound strange, but the house financing has not been finalized yet either.
D
daniels875 Sep 2017 07:50We achieved KfW55 efficiency with minimal extra effort. Around 500€. I think it was slightly thicker perimeter insulation.
Otherwise, standard.
-Unheated utility basement (except for the stairwell) and two full floors (T9 bricks)
-Triple glazing
-Controlled mechanical ventilation system
-Air-to-water heat pump
I consider heating in the (utility) basement unnecessary for us. It’s actually an advantage for the workshop and gym room to be a bit cooler, and it doesn’t matter for the storage room. The heating room is always a bit warmer anyway, so I just leave the door to the workshop open.
Otherwise, standard.
-Unheated utility basement (except for the stairwell) and two full floors (T9 bricks)
-Triple glazing
-Controlled mechanical ventilation system
-Air-to-water heat pump
I consider heating in the (utility) basement unnecessary for us. It’s actually an advantage for the workshop and gym room to be a bit cooler, and it doesn’t matter for the storage room. The heating room is always a bit warmer anyway, so I just leave the door to the workshop open.
That all sounds quite good. The option with an unheated basement also seems pretty reasonable. It would be my favorite if my wife didn’t have the silly idea of heating a room (playroom or hobby room with 30m² (323 ft²)).
Could there be issues with moisture and mold if the basement is heated unevenly? I’m a bit concerned about that.
Could there be issues with moisture and mold if the basement is heated unevenly? I’m a bit concerned about that.
D
daniels875 Sep 2017 11:17We don’t even have a mechanical ventilation system in the basement. However, it is completely dry now. For the first 3-4 months, I kept the doors to the stairwell open, which was enough.
If the room is not used regularly (as is often the case with basements), I would only install an electric heater. If you include the basement area in the heating load calculation, the heating system might be oversized, which reduces efficiency at low load. In short, if the basement heating is off, an air-to-water heat pump will consume more energy compared to a smaller heat pump sized without the basement.
If the room is not used regularly (as is often the case with basements), I would only install an electric heater. If you include the basement area in the heating load calculation, the heating system might be oversized, which reduces efficiency at low load. In short, if the basement heating is off, an air-to-water heat pump will consume more energy compared to a smaller heat pump sized without the basement.
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