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.
H
hampshire20 Jul 2020 13:24exto1791 schrieb:
Is the heat pump really so electricity-intensive that a photovoltaic system pays off very quickly? Are there any statistics or figures from your experience with single-family homes? Yes, the heat pump consumes electricity but, when properly configured, it has good efficiency. In winter, it uses more energy because more heating is needed and efficiency decreases with lower outdoor temperatures. Still, it’s a good system. The only downside is that you generate very little photovoltaic electricity during winter.
exto1791 schrieb:
Since the feed-in tariff is currently very low, I’m wondering if I should install photovoltaic panels on the roof right away or hold off for now and just have the conduits laid for it. Nowadays, the system no longer pays off primarily through the feed-in tariff (or export tariff), but through self-consumption. You produce electricity at 6-8 cents and replace grid electricity that costs 27-33 cents. That’s where the benefit lies, and that’s how a photovoltaic system pays off, with or without a heat pump.
Ybias78 schrieb:
What are the costs for such a system?A reasonable price is about 1000€/kWp. But you first have to find that. For us, it will be 1600€, but we have a storage system included, and unfortunately, I don’t know what that costs.You don’t need to be a prophet to predict that after the next election, every position related to the environment will be held by a Green Party minister. And they are not exactly known for being particularly rational. Personally, I wouldn’t install a fossil fuel heating system anymore.
We have produced 6,200kWh of electricity with a 9.2kWp system from January 17th until now, of which 1,500kWh were generated between January 17th and April 1st, during the heating season. Even in winter, the roof produces a significant amount of power. So far, we have generated 55% of our electricity demand ourselves, without any storage.
@Traube348, with solar systems, you usually have a buffer tank of 400–800 liters (105–210 gallons), which also requires some space.
We have produced 6,200kWh of electricity with a 9.2kWp system from January 17th until now, of which 1,500kWh were generated between January 17th and April 1st, during the heating season. Even in winter, the roof produces a significant amount of power. So far, we have generated 55% of our electricity demand ourselves, without any storage.
@Traube348, with solar systems, you usually have a buffer tank of 400–800 liters (105–210 gallons), which also requires some space.
Correct. The storage tank is sized not according to the number of people, but based on the size of the solar thermal system.
It needs to be large enough because especially in summer, the water heats up very quickly and the system stagnates. This puts significant stress on the heat transfer fluid in the system.
However, the storage tank should not be too large either, as during transitional seasons, this can prevent the system from operating effectively.
Additionally, there must be sufficient space for connecting and maintaining all components.
Furthermore, there are regulations from the utility provider.
I am skeptical about manipulating solar thermal system designs to look better on paper. There are cases where the requirements can be met through controlled residential ventilation, but a professional must perform the calculations.
It needs to be large enough because especially in summer, the water heats up very quickly and the system stagnates. This puts significant stress on the heat transfer fluid in the system.
However, the storage tank should not be too large either, as during transitional seasons, this can prevent the system from operating effectively.
Additionally, there must be sufficient space for connecting and maintaining all components.
Furthermore, there are regulations from the utility provider.
I am skeptical about manipulating solar thermal system designs to look better on paper. There are cases where the requirements can be met through controlled residential ventilation, but a professional must perform the calculations.
Joedreck schrieb:
Correct. The storage tank is not sized based on the number of people, but rather on the size of the solar thermal system.
It needs to be large enough because, especially in summer, the water heats up very quickly, causing the system to stagnate. This puts significant stress on the heat transfer fluid in the system.
However, the storage tank should not be too large either, as during transitional seasons, nothing will happen at all.
Additionally, there must be enough space to connect and maintain everything.
There are also regulations from the utility provider.
I am not a fan of "optimizing" solar thermal systems on paper. There are cases where the necessary conditions are met through controlled residential ventilation, but a professional must perform the calculations. We wanted to have a 175-liter (about 46 gallons) storage tank because, in my opinion, a 300-liter (about 79 gallons) tank is not necessary for a family of three. Now you say that it depends on the system. Could you please explain this in more detail?
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