ᐅ Construction Project – Ventilation System, Heating – Your Experiences?
Created on: 16 Dec 2019 19:17
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Nicon1001
Hello everyone,
After researching prefab houses in this forum over two years ago and coming across several posts that introduced me to the option of a solid (masonry) house, we have now decided to build such a solid house. We purchased the corresponding plot in Rhineland-Palatinate this month. We have successfully completed the first meeting with the architect (who was recommended to us by several friends). The meeting was very pleasant, and we were able to present our ideas. The next step is for him to create an initial design, which we will then review to see if it meets our preferences and to discuss any changes we want.
Since I have spent a lot of time in the last two years reading forums and many construction websites, I have come across many opinions and have already asked the architect for his thoughts on some issues. I want to pose these questions to you as well to get some additional feedback specific to my case. By the way, the building project will be a one-and-a-half-story single-family house with a pitched roof and 145-150 sqm (1560-1615 sq ft) of living space, without a basement.
1. We would like to have a central ventilation system. He advises against it due to the high costs (apparently around 18,000 - 20,000) and recommends the traditional use of windows. Is this cost range of 18,000 - 20,000 realistic? I had read something about around 12,000.
2. Regarding the heating system... we would like 3-4 sqm (32-43 sq ft) of solar thermal collectors for domestic hot water. Personally, I would probably have chosen a gas condensing boiler for the underfloor heating. He recommends an air-source heat pump. I have read that these can consume a lot of electricity, plus I wouldn’t be thrilled about even a slight humming noise outside. I’m probably not too satisfied with the gas condensing boiler either. The ground here is heavily rocky (slate mountain range). He considers any drilling into the ground risky due to possible rapidly increasing costs. He also doesn’t favor horizontal ground loop collectors, because they might cause problems with plant roots. Somehow it feels like everything has its downsides. What heating types do you have? What were the costs, and how satisfied are you? How are the running costs?
3. We love the clinker brick look. We would like to cover the entire façade with genuine clinker bricks. He advised us to preferably involve companies from North Rhine-Westphalia or Northern Germany, where it is common and they have expertise. I agree with that. What is the current cost per sqm for clinker bricks? Has anyone recently had this done? How long did it take? Clinker slips (thin facing bricks) are not an option for us.
4. If possible, we want to aim for KfW 55 standard (energy-efficient building standard). With the ventilation system and solar thermal, I think we are pretty well set in that direction. Then there is of course the question of the building material. He recommends monolithic Poroton blocks. But one could also use presumably cheaper pumice blocks if it really is a clinker brick masonry. Would pumice plus clinker be sufficient for KfW 55? External thermal insulation composite systems (ETICS, known as WDVS in German) are not planned. What is the price difference between Poroton and pumice?
If you have any questions, I will gladly try to answer them.
Thanks in advance, and please don’t be too harsh on me.
After researching prefab houses in this forum over two years ago and coming across several posts that introduced me to the option of a solid (masonry) house, we have now decided to build such a solid house. We purchased the corresponding plot in Rhineland-Palatinate this month. We have successfully completed the first meeting with the architect (who was recommended to us by several friends). The meeting was very pleasant, and we were able to present our ideas. The next step is for him to create an initial design, which we will then review to see if it meets our preferences and to discuss any changes we want.
Since I have spent a lot of time in the last two years reading forums and many construction websites, I have come across many opinions and have already asked the architect for his thoughts on some issues. I want to pose these questions to you as well to get some additional feedback specific to my case. By the way, the building project will be a one-and-a-half-story single-family house with a pitched roof and 145-150 sqm (1560-1615 sq ft) of living space, without a basement.
1. We would like to have a central ventilation system. He advises against it due to the high costs (apparently around 18,000 - 20,000) and recommends the traditional use of windows. Is this cost range of 18,000 - 20,000 realistic? I had read something about around 12,000.
2. Regarding the heating system... we would like 3-4 sqm (32-43 sq ft) of solar thermal collectors for domestic hot water. Personally, I would probably have chosen a gas condensing boiler for the underfloor heating. He recommends an air-source heat pump. I have read that these can consume a lot of electricity, plus I wouldn’t be thrilled about even a slight humming noise outside. I’m probably not too satisfied with the gas condensing boiler either. The ground here is heavily rocky (slate mountain range). He considers any drilling into the ground risky due to possible rapidly increasing costs. He also doesn’t favor horizontal ground loop collectors, because they might cause problems with plant roots. Somehow it feels like everything has its downsides. What heating types do you have? What were the costs, and how satisfied are you? How are the running costs?
3. We love the clinker brick look. We would like to cover the entire façade with genuine clinker bricks. He advised us to preferably involve companies from North Rhine-Westphalia or Northern Germany, where it is common and they have expertise. I agree with that. What is the current cost per sqm for clinker bricks? Has anyone recently had this done? How long did it take? Clinker slips (thin facing bricks) are not an option for us.
4. If possible, we want to aim for KfW 55 standard (energy-efficient building standard). With the ventilation system and solar thermal, I think we are pretty well set in that direction. Then there is of course the question of the building material. He recommends monolithic Poroton blocks. But one could also use presumably cheaper pumice blocks if it really is a clinker brick masonry. Would pumice plus clinker be sufficient for KfW 55? External thermal insulation composite systems (ETICS, known as WDVS in German) are not planned. What is the price difference between Poroton and pumice?
If you have any questions, I will gladly try to answer them.
Thanks in advance, and please don’t be too harsh on me.
Our mechanical ventilation system (for 180sqm (1,938 sqft)) cost about 12,000 euros, definitely not more, and I would never want to go without it again. To ventilate properly, you would need to open all the windows about five times a day, but then in winter the house gets freezing cold, and in summer you get the heat along with about 30 flies inside. Also, people usually have some kind of decoration on the windowsill, so you can’t just quickly open every window, or like in our case, all the window locks are secured.
It’s simply a huge gain in comfort to have mechanical ventilation, with fresh air constantly coming in that is even preheated.
When it comes to heating, it’s a matter of personal preference. We have gas because the noise from an air-to-water heat pump bothers me, and we didn’t want to disturb our neighbors either.
Best regards,
Sabine
It’s simply a huge gain in comfort to have mechanical ventilation, with fresh air constantly coming in that is even preheated.
When it comes to heating, it’s a matter of personal preference. We have gas because the noise from an air-to-water heat pump bothers me, and we didn’t want to disturb our neighbors either.
Best regards,
Sabine
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Daniel-Sp17 Dec 2019 08:25kaho674 schrieb:
Why not? Is it that expensive?
My dad has it on the roof and he’s enthusiastic about it. Ok, he’s always been interested in technology anyway. But he says he gets boiling water from the roof on sunny winter days. Investment costs minus expected savings.
If you decide to use a heat pump, there are other reasons to avoid this. You then mix a high-temperature system with a low-temperature system. To make that work, you need a system with a mixing valve. This complicates the control, and most heating installers already struggle with heat pumps without solar thermal systems. You can imagine the outcome. The efficiency of the heat pump also suffers even with an optimally controlled system, which brings us back to the first sentence.
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boxandroof17 Dec 2019 08:42Solar thermal systems are nowadays mostly installed just to meet energy saving regulations for gas heating. In that case, they might be cost-effective since it’s the cheapest way to support gas. Some general contractors opt for mediocre heat pump solutions instead because they are cheaper than combining gas and solar thermal, and because heat pumps help present consumption figures more favorably on paper, even though real insulation standards might be compromised.
Controlled ventilation is purely a comfort decision for us, costing around €11,000. It doesn’t save energy but was the best choice for us to install.
Heat pumps are suitable for new builds. However, the planning—including the design of underfloor heating—must be closely supervised by the homeowner.
Whether the heat pump pays off compared to gas depends on the purchase price. The more the homeowner manages the process, the more savings can be realized compared to gas. See the notes on trench collectors by Daniel.
Gas has the advantage that planning mistakes have little impact on operational costs, meaning you don’t have to manage much yourself and can expect moderate consumption. However, if you later switch from gas to a heat pump, it would have been better to plan properly from the start (underfloor heating).
In my opinion, the best concept is:
- Insulation roughly to KfW55 standard, depending on costs
- Trench collector + government subsidy (BAFA) or an air-to-water heat pump, ideally purchased and/or strongly coordinated by yourself
- Roof filled with photovoltaic panels as much as possible
- Controlled ventilation as an option
Our architect had only opinions regarding the technology. Had we followed those, we would have ended up with higher initial costs and consumption.
Controlled ventilation is purely a comfort decision for us, costing around €11,000. It doesn’t save energy but was the best choice for us to install.
Heat pumps are suitable for new builds. However, the planning—including the design of underfloor heating—must be closely supervised by the homeowner.
Whether the heat pump pays off compared to gas depends on the purchase price. The more the homeowner manages the process, the more savings can be realized compared to gas. See the notes on trench collectors by Daniel.
Gas has the advantage that planning mistakes have little impact on operational costs, meaning you don’t have to manage much yourself and can expect moderate consumption. However, if you later switch from gas to a heat pump, it would have been better to plan properly from the start (underfloor heating).
In my opinion, the best concept is:
- Insulation roughly to KfW55 standard, depending on costs
- Trench collector + government subsidy (BAFA) or an air-to-water heat pump, ideally purchased and/or strongly coordinated by yourself
- Roof filled with photovoltaic panels as much as possible
- Controlled ventilation as an option
Our architect had only opinions regarding the technology. Had we followed those, we would have ended up with higher initial costs and consumption.
L
ludwig88sta17 Dec 2019 10:42boxandroof schrieb:
Today, solar thermal systems are mostly installed just to fulfill energy-saving regulations for gas heating. In that case, they might make sense economically, as it can be the cheapest way to support gas use. Some general contractors (GCs) install mediocre heat pump systems instead, because it’s cheaper than combining gas and solar thermal, and because the heat pump helps to make the energy consumption look better on paper, while allowing savings on actual insulation.
Heat pumps are suitable for new builds. However, the planning, including the design of the underfloor heating, definitely needs to be closely monitored by the homeowner.
Whether a heat pump is cost-effective depends on the price paid for it. The more the homeowner is involved, the more can be saved compared to gas. See the notes on the horizontal trench collector from Daniel.
Gas has the advantage that planning mistakes rarely affect operating costs, meaning you don’t have to manage it closely and can expect moderate energy use. But if you switch from gas to a heat pump later, it would have been better to plan properly from the start (including underfloor heating).
Good post!
Still, I have a few questions for clarification: why do planning mistakes in a gas heating system hardly affect energy consumption? What do you mean by planning mistakes? Like choosing a heating system that’s too large or too small? I imagine it’s also difficult to select the right capacity/size for a heat pump.
But since you mentioned underfloor heating — I assume that can be used effectively with both a gas boiler and an air-water heat pump, right?
Also, why do some general contractors install lower-quality heat pump systems and save money on insulation? Poor insulation means the heat pump has to work harder (like using the electric backup heater more often), so how would they then achieve “good” consumption figures on paper?
When you say the homeowner should “oversee” the heat pump, do you mean being involved in the proper configuration afterwards or in the selection process?
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boxandroof17 Dec 2019 10:45There are many pitfalls with heat pumps. Buffer tanks and especially poorly designed underfloor heating systems. Just search online—there are hundreds of discussions on this topic.
With gas heating, you simply raise the temperature of the heating system, and that’s it. With heat pumps, however, every degree costs efficiency. Additionally, heat pumps are often operated incorrectly: electric heating elements, incorrect heating curves, and so on. These are all risks that don’t usually exist with gas heating.
I am absolutely pro-heat pump, but heat pumps are unfortunately not a simple solution.
With gas heating, you simply raise the temperature of the heating system, and that’s it. With heat pumps, however, every degree costs efficiency. Additionally, heat pumps are often operated incorrectly: electric heating elements, incorrect heating curves, and so on. These are all risks that don’t usually exist with gas heating.
I am absolutely pro-heat pump, but heat pumps are unfortunately not a simple solution.
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