ᐅ New Single-Family Home Built to KfW55 Standard – Which Heating System to Choose?
Created on: 19 Jul 2020 12:19
T
Traube348
Hello everyone,
I have read many articles and would now like to benefit from the extensive knowledge of the members here.
A brief overview of my building project:
- Single-family house with approximately 160sqm (1,722 sq ft) of living space
- No basement, 2 full floors with an unfinished attic
- Relatively large window areas and an open-plan design with a staircase in the living area
- Underfloor heating throughout the house with tile flooring
- KfW 55 standard with timber frame construction
- A wood-burning stove will be installed
Unfortunately, I have little experience in this area and rely on recommendations from others regarding heating.
On the ground floor, we have a utility room of 8sqm (86 sq ft) where we would like to accommodate all the technical equipment.
The builder recommends installing a central ventilation system, which we would like to do.
Now to my question:
There is a gas connection in our building area, and a friend told me we should definitely heat with a gas boiler. To meet the KfW standard, according to the energy consultant, we still need to install 9sqm (97 sq ft) of solar panels on the roof.
A heating engineer friend advises: choose an air-to-water heat pump – split system Weishaupt LS 8-BREK – so you can avoid the solar requirement.
I have requested quotes for both options from different heating engineers, and they come out roughly the same in price.
Since I have heard many statements opposing air-to-water heat pumps, I tend to prefer gas.
However, the main challenge is the limited space in the utility room. In addition to the heating system, the two-flue fireplace, and the ventilation system, the electrical control cabinet as well as the washing machine and dryer are also planned to be located there.
Is there anyone who has faced a similar space issue?
What would you recommend?
Thank you very much in advance for your help.
I have read many articles and would now like to benefit from the extensive knowledge of the members here.
A brief overview of my building project:
- Single-family house with approximately 160sqm (1,722 sq ft) of living space
- No basement, 2 full floors with an unfinished attic
- Relatively large window areas and an open-plan design with a staircase in the living area
- Underfloor heating throughout the house with tile flooring
- KfW 55 standard with timber frame construction
- A wood-burning stove will be installed
Unfortunately, I have little experience in this area and rely on recommendations from others regarding heating.
On the ground floor, we have a utility room of 8sqm (86 sq ft) where we would like to accommodate all the technical equipment.
The builder recommends installing a central ventilation system, which we would like to do.
Now to my question:
There is a gas connection in our building area, and a friend told me we should definitely heat with a gas boiler. To meet the KfW standard, according to the energy consultant, we still need to install 9sqm (97 sq ft) of solar panels on the roof.
A heating engineer friend advises: choose an air-to-water heat pump – split system Weishaupt LS 8-BREK – so you can avoid the solar requirement.
I have requested quotes for both options from different heating engineers, and they come out roughly the same in price.
Since I have heard many statements opposing air-to-water heat pumps, I tend to prefer gas.
However, the main challenge is the limited space in the utility room. In addition to the heating system, the two-flue fireplace, and the ventilation system, the electrical control cabinet as well as the washing machine and dryer are also planned to be located there.
Is there anyone who has faced a similar space issue?
What would you recommend?
Thank you very much in advance for your help.
N
nordanney22 Jul 2020 21:33DaSch17 schrieb:
So it might be possible to use it in a 40 Plus single-family house—provided the overall concept is consistent—right?Possible, but probably not practical. It’s only a 40 standard house (which is not much better than a 55 standard house), not a passive house. High desired room temperatures will come with corresponding energy consumption. You definitely won’t have warm feet. Alternatively, you’ll be stoking the wood stove regularly. Of course, it is significantly cheaper than installing conventional heating.
That’s quite adventurous, electric underfloor heating. It reminds me of storage heaters, which are no longer used for good reasons.
Consider this: a well-insulated house needs very little gas. So, it doesn’t harm the environment much, requires a small investment, and offers high flexibility. What’s the advantage of a heat pump then? With solar panels, you can also generate hot water for free and in an environmentally friendly way.
However, these systems are very cheap, have no political lobby, and have increasingly been criticized by activists like Greta.
In my experience, air-to-air and air-to-water heat pumps require excellent planning, execution, and very careful commissioning. They should only be used in houses built to KfW55 standards or better. Only then are they an ecological, economical, and comfortable way to heat a home. But there often remain noise issues, either inside the house or outside if the unit is installed outdoors. Especially in the low-frequency range, this frequently causes conflicts with neighbors.
In practice (I know dozens of heat pump owners), the situation is quite different. Most heating contractors fail to meet all these prerequisites. What remains is a frustrated customer who has invested a lot of money in a modern heating system, faces high running costs, and is cold in the bathroom during winter. Then the old fan heater gets dragged out again.
The environment also suffers in this case. Only the heating contractor and energy provider are happy—they make a fortune.
Consider this: a well-insulated house needs very little gas. So, it doesn’t harm the environment much, requires a small investment, and offers high flexibility. What’s the advantage of a heat pump then? With solar panels, you can also generate hot water for free and in an environmentally friendly way.
However, these systems are very cheap, have no political lobby, and have increasingly been criticized by activists like Greta.
In my experience, air-to-air and air-to-water heat pumps require excellent planning, execution, and very careful commissioning. They should only be used in houses built to KfW55 standards or better. Only then are they an ecological, economical, and comfortable way to heat a home. But there often remain noise issues, either inside the house or outside if the unit is installed outdoors. Especially in the low-frequency range, this frequently causes conflicts with neighbors.
In practice (I know dozens of heat pump owners), the situation is quite different. Most heating contractors fail to meet all these prerequisites. What remains is a frustrated customer who has invested a lot of money in a modern heating system, faces high running costs, and is cold in the bathroom during winter. Then the old fan heater gets dragged out again.
The environment also suffers in this case. Only the heating contractor and energy provider are happy—they make a fortune.
Bookstar schrieb:
Just think about it: a house that is so well insulated requires very little gas. So, it doesn’t really harm the environment much, involves low investment, and offers high flexibility. What is the advantage of a heat pump? With solar you can also produce your hot water for free and in an environmentally friendly way.I completely agree with you. Personally, I would also prefer gas. However, in most new housing developments—like ours—gas lines are unfortunately no longer being installed.
So, the only options left are air-source heat pumps, air-to-water heat pumps, or ground-source (geothermal) heat pumps...
Regarding the cost advantage of using the additional heating element of the Proxon, we are now not so sure.
Despite extensive research, there are no real calculation examples available online. We have only found consumption calculations assuming that the electric underfloor heating is used exclusively as a heat source in the bathroom, requiring 0.15 kWh/sqm (0.015 kWh/sqft).
The calculation of the monthly costs is as follows:
- 21 sqm (226 sqft) bathroom (15 sqm and 6 sqm), of which only 13 sqm (140 sqft) is to be heated (the rest includes shower, bathtub, toilet, etc.)
- Consumption 0.15 kWh/sqm (0.015 kWh/sqft)
- Heating duration including preheating time: 1 hour in the morning; 2 hours in the evening
This means:
13 sqm x 0.15 kWh x 3 hours = 5.85 kWh/day x 0.30 €/kWh = 1.76 €/day
Assuming the additional heating of the bathroom is required for 6 months (=183 days).
This results—in a scenario without considering photovoltaics with battery storage— in 1.76 €/day x 183 days = 322.08 €/year or 26.84 €/month.
Does this seem accurate? Or are the costs lower because the electric underfloor heating only needs to temporarily raise the Proxon’s 21°C (70°F) to 23-24°C (73-75°F)?
Despite extensive research, there are no real calculation examples available online. We have only found consumption calculations assuming that the electric underfloor heating is used exclusively as a heat source in the bathroom, requiring 0.15 kWh/sqm (0.015 kWh/sqft).
The calculation of the monthly costs is as follows:
- 21 sqm (226 sqft) bathroom (15 sqm and 6 sqm), of which only 13 sqm (140 sqft) is to be heated (the rest includes shower, bathtub, toilet, etc.)
- Consumption 0.15 kWh/sqm (0.015 kWh/sqft)
- Heating duration including preheating time: 1 hour in the morning; 2 hours in the evening
This means:
13 sqm x 0.15 kWh x 3 hours = 5.85 kWh/day x 0.30 €/kWh = 1.76 €/day
Assuming the additional heating of the bathroom is required for 6 months (=183 days).
This results—in a scenario without considering photovoltaics with battery storage— in 1.76 €/day x 183 days = 322.08 €/year or 26.84 €/month.
Does this seem accurate? Or are the costs lower because the electric underfloor heating only needs to temporarily raise the Proxon’s 21°C (70°F) to 23-24°C (73-75°F)?
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