Hello dear readers,
We are currently making concrete plans for our new build next year. Key details: single-family house, about 130sqm (1400 sq ft), with a basement.
Bien-Zenker has made it to our shortlist. The price-performance ratio seems reasonable, we like the floor plan, and it is also a well-established large home builder.
For heating, we were offered a brine-to-water heat pump with underfloor heating (which we wanted) and a controlled mechanical ventilation system with heat recovery.
Our budget is limited, and we would go for the so-called Efficiency House 55 thermal wall with a U-value of 0.142 W/(sqm·K).
Overall, the house would meet the Efficiency House 70 standard.
I’m no expert, but compared to other manufacturers, this value is average. The "standard wall" from Kampa, for example, would be better.
What do you think about this building services offer overall?
Is the heat pump cost-effective over the years compared to the standard gas condensing boiler?
Many thanks from a beginner for your support and answers.
We are currently making concrete plans for our new build next year. Key details: single-family house, about 130sqm (1400 sq ft), with a basement.
Bien-Zenker has made it to our shortlist. The price-performance ratio seems reasonable, we like the floor plan, and it is also a well-established large home builder.
For heating, we were offered a brine-to-water heat pump with underfloor heating (which we wanted) and a controlled mechanical ventilation system with heat recovery.
Our budget is limited, and we would go for the so-called Efficiency House 55 thermal wall with a U-value of 0.142 W/(sqm·K).
Overall, the house would meet the Efficiency House 70 standard.
I’m no expert, but compared to other manufacturers, this value is average. The "standard wall" from Kampa, for example, would be better.
What do you think about this building services offer overall?
Is the heat pump cost-effective over the years compared to the standard gas condensing boiler?
Many thanks from a beginner for your support and answers.
Cascada schrieb:
... We have now also been offered another alternative: gas boiler, underfloor heating, and ventilation/heat recovery.
If you exclude the ventilation, this option would be about 14,000 euros cheaper than the ground source heat pump. Considering only the investment costs is not really sufficient. You need to look at the total costs. Check my profile; there is an image about this. Whether the ventilation might be the deciding factor from a primary energy perspective I cannot assess from a distance, but I suspect that, from a primary energy point of view, a solar thermal system might become necessary. After all, the Renewable Energy Heat Act (EEWG) sets requirements regarding the use of alternative energy sources. Unless there are compensatory measures or exemptions! The underfloor heating should definitely be optimized for a heat pump, even if currently a gas condensing boiler is planned as the heat generator.
Cascada schrieb:
... In my opinion, ventilation should be included for indoor ecological and comfort reasons (no mold, no incorrect airing during the heating period, etc.), even if the electricity bill is somewhat higher. I have written quite a bit here already about the pros and cons of ventilation, for example: https://www.hausbau-forum.de/klima/3571-kfw-70-ohne-lüftungsanlage-2.html#post23614 Cascada schrieb:
... Would the gas boiler be an adequate alternative to the ground source heat pump? Gas and air source heat pumps often compete very closely. The ground source heat pump becomes interesting despite higher costs when the conditions require an exceptionally high annual performance factor (seasonal efficiency). As long as these conditions are unknown, it remains guesswork. 😉 Best regards
Thank you €uro.
So, it is now almost certain that we will use gas with underfloor heating and KWB/heat recovery.
What does it mean that the underfloor heating must also be optimized for a heat pump? I had thought so far that underfloor heating runs at low temperatures and is therefore suitable for a heat pump. From our perspective, this would make us future-proof, meaning that even in about 15 years a heat pump could be retrofitted without any problems because the "hardware"—the underfloor heating—is already installed, and only the geothermal drilling and heat pump would need to be added.
We want the KWB/heat recovery system for several reasons. OK, mold and humidity during the heating period are also a concern (though we are not overly worried), but also a certain level of comfort, which is affordable considering the ongoing costs. There would also be no ventilation heat losses in winter. And retrofitting later would practically not be feasible.
After reading various posts in this forum, we are also moving away from a solar thermal system on the roof, although I used to think that it would cover all hot water supply in summer and save a few euros on sunny days in winter (heating support).
But apparently, the investment costs are difficult to recoup...?
Another option to consider (but I will probably have to ask the banker) is a photovoltaic system on the roof. I’m not sure whether, due to reduced feed-in tariffs, it still pays for itself and covers our own electricity consumption after 15 years...?
What do you think about this?
Best regards...
So, it is now almost certain that we will use gas with underfloor heating and KWB/heat recovery.
What does it mean that the underfloor heating must also be optimized for a heat pump? I had thought so far that underfloor heating runs at low temperatures and is therefore suitable for a heat pump. From our perspective, this would make us future-proof, meaning that even in about 15 years a heat pump could be retrofitted without any problems because the "hardware"—the underfloor heating—is already installed, and only the geothermal drilling and heat pump would need to be added.
We want the KWB/heat recovery system for several reasons. OK, mold and humidity during the heating period are also a concern (though we are not overly worried), but also a certain level of comfort, which is affordable considering the ongoing costs. There would also be no ventilation heat losses in winter. And retrofitting later would practically not be feasible.
After reading various posts in this forum, we are also moving away from a solar thermal system on the roof, although I used to think that it would cover all hot water supply in summer and save a few euros on sunny days in winter (heating support).
But apparently, the investment costs are difficult to recoup...?
Another option to consider (but I will probably have to ask the banker) is a photovoltaic system on the roof. I’m not sure whether, due to reduced feed-in tariffs, it still pays for itself and covers our own electricity consumption after 15 years...?
What do you think about this?
Best regards...
B
Bauexperte12 Apr 2011 10:30Hello,
If the building envelope is already designed to KfW 70 standards, your assumption is indeed correct 🙂
Decentralized systems can be retrofitted anytime with minimal mess. However, if the budget allows, I would recommend installing a ventilation system during new construction. These systems are not very expensive, although without heat recovery they are not really advisable in conventional building construction.
Kind regards
Cascada schrieb:
So, in our opinion, we would be future-proof, meaning that even in about 15 years a heat pump could be easily retrofitted because the "hardware" of the underfloor heating is already in place, and "only" the deep drilling and heat pump would need to be installed.
If the building envelope is already designed to KfW 70 standards, your assumption is indeed correct 🙂
Cascada schrieb:
And a retrofit later would basically not be feasible.
Decentralized systems can be retrofitted anytime with minimal mess. However, if the budget allows, I would recommend installing a ventilation system during new construction. These systems are not very expensive, although without heat recovery they are not really advisable in conventional building construction.
Kind regards
We have now read quite a bit about brine-to-water heat pumps with trench collectors instead of deep drilling. The price is roughly comparable to gas plus solar.
I know that no concrete statements are possible without a heating load calculation, but in general, it sounds interesting. The performance is said to be similar to those with deep drilling.
Any statements or experiences?
Best regards...
I know that no concrete statements are possible without a heating load calculation, but in general, it sounds interesting. The performance is said to be similar to those with deep drilling.
Any statements or experiences?
Best regards...
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