ᐅ Which type of heating system is recommended for a KfW 55 energy-efficient house?
Created on: 28 Aug 2011 21:12
A
amazingbee
Hello! We are currently planning a house and, since this is not something you do often, we have many questions. Due to the development plan for our plot, we are required to build a KfW 55 energy efficiency house and are now unsure about what type of heating system we need. Builders have given us different advice!
Is it possible to install a standard gas condensing boiler combined with solar water heating, or do we have to use geothermal or air-source heat pumps?
I would appreciate any answers!
Is it possible to install a standard gas condensing boiler combined with solar water heating, or do we have to use geothermal or air-source heat pumps?
I would appreciate any answers!
L
Lebensprojekt31 May 2015 23:45Hello,
I would like to revive this older thread.
We also aim for around KFW 55 standard, but without an air-to-water heat pump; instead, we plan to use a gas boiler. Our design includes a monolithic construction with Poroton T9 blocks, 36.5cm (14.4 inches) thick. Passive house windows (triple glazing with a U-value of 0.83) and insulated ground slab/floor ceiling.
We are not interested in external thermal insulation composite systems (ETICS). In any case, we do not want any polystyrene in our house.
Now the question is, what else would we need to do to achieve this? The building envelope should be sufficient, but maybe increasing the wall thickness to 42.5cm (16.7 inches) would help?
Best regards
I would like to revive this older thread.
We also aim for around KFW 55 standard, but without an air-to-water heat pump; instead, we plan to use a gas boiler. Our design includes a monolithic construction with Poroton T9 blocks, 36.5cm (14.4 inches) thick. Passive house windows (triple glazing with a U-value of 0.83) and insulated ground slab/floor ceiling.
We are not interested in external thermal insulation composite systems (ETICS). In any case, we do not want any polystyrene in our house.
Now the question is, what else would we need to do to achieve this? The building envelope should be sufficient, but maybe increasing the wall thickness to 42.5cm (16.7 inches) would help?
Best regards
B
Bauexperte1 Jun 2015 00:12Lebensprojekt schrieb:
The building envelope should be fine, maybe increase the wall thickness to 42.5 cm (17 inches)? "Believing" won’t get you anywhere; ask your energy consultant, they need to do the calculations.
I’m sure that even with an additional 42.5 cm (17 inches) and mechanical ventilation with heat recovery, you won’t even come close to meeting KfW 55 standards.
Regards, Bauexperte
L
Lebensprojekt1 Jun 2015 00:48I forgot to mention, a controlled residential ventilation system with heat recovery is, of course, included in the plan....
L
Lebensprojekt1 Jun 2015 10:16The main issue probably remains the absence of a heat pump, which, upon closer examination, isn’t really environmentally friendly due to its high electricity consumption. Still, heat pumps are subsidized.
Of course, we are in contact with an energy consultant, who is currently revising the floor plan. Since the energy consultant costs money, we need to wait for the details.
That’s why I’m asking here in the forum: who has achieved KFW 55, or who knows how it can be achieved?
Regards
Of course, we are in contact with an energy consultant, who is currently revising the floor plan. Since the energy consultant costs money, we need to wait for the details.
That’s why I’m asking here in the forum: who has achieved KFW 55, or who knows how it can be achieved?
Regards
S
Sebastian791 Jun 2015 10:39It depends on the heat pump when you refer to high electricity consumption – a ground source heat pump, when properly sized, does not have high consumption. In terms of operating costs, it can even be cheaper than gas.
We have a house equivalent to KfW 56 standard with calcium silicate bricks and 14 cm (5.5 inches) of mineral wool insulation, windows with U-values of 0.6, 24 cm (9.5 inches) of rafter insulation (pitched roof at 35°), 10 cm (4 inches) of perimeter insulation on the basement, no floor slab insulation, and of course a ground source heat pump and a mechanical ventilation system with heat recovery.
Just as a rough outline...
We have a house equivalent to KfW 56 standard with calcium silicate bricks and 14 cm (5.5 inches) of mineral wool insulation, windows with U-values of 0.6, 24 cm (9.5 inches) of rafter insulation (pitched roof at 35°), 10 cm (4 inches) of perimeter insulation on the basement, no floor slab insulation, and of course a ground source heat pump and a mechanical ventilation system with heat recovery.
Just as a rough outline...
L
Lebensprojekt1 Jun 2015 13:12Sure, a ground source heat pump will definitely have lower energy consumption. However, the additional investment costs of about 20,000 euros more are quite significant, and from what I’ve learned, there is high maintenance effort and corresponding costs to consider with heat pumps.
Our main goal is to achieve this with a small and reasonable investment. If that’s not possible, we’ll have to stick with the KfW 70 standard.
Apart from the KfW aspect, low energy consumption of our future house is our top priority, which is why we are also considering the KfW 55 standard if we already plan for a good building envelope.
Best regards
Our main goal is to achieve this with a small and reasonable investment. If that’s not possible, we’ll have to stick with the KfW 70 standard.
Apart from the KfW aspect, low energy consumption of our future house is our top priority, which is why we are also considering the KfW 55 standard if we already plan for a good building envelope.
Best regards
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