ᐅ Construction Project – Ventilation System, Heating – Your Experiences?
Created on: 16 Dec 2019 19:17
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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.
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boxandroof17 Dec 2019 10:46ludwig88sta schrieb:
Oh, and why do some general contractors install rather poor heat pumps and cut costs on insulation? Poor insulation means the heat pump has to work harder (activating the electric backup earlier, etc.), so you won’t see good consumption figures on paper anymore.The general contractor doesn’t care about your energy consumption.Take charge yourself: study the subject, avoid planning errors in hydraulics and underfloor heating (heating load and installation plans per room). Ideally, install the horizontal ground loop yourself and purchase the heat pump independently or negotiate with the heating installer, as this can save significant money. Alternatively, buy a compact air-to-water heat pump yourself. When building with an architect instead of a general contractor, this is an option if you have the time to manage it.
We were recommended the combination with ST by the energy consultant – as I said, I’m now curious to see our energy consumption once I have a better overview. At the moment, we are still working on finding the optimal setting for our heating system – that will probably take some time. Currently, our flow temperature is definitely too high (40°C (104°F)), but in the beginning, it was really cold. I believe there is still a lot of potential for optimization. However, we first need to thoroughly familiarize ourselves with our building’s technical systems overall – we haven’t had the chance to do that yet. An introduction from the installer provided by our general contractor is also still pending (it will happen), so I’m still relaxed about it.
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boxandroof17 Dec 2019 11:14With gas, it’s not as critical... but even there, you can probably optimize by a few percent to make better use of the condensing effect.
A temperature of 40°C (104°F) with a heat pump generally means roughly double the electricity consumption compared to what would actually be needed. With the current weather, we are running at around 24-27°C (75-81°F) supply temperature. This is only possible if the underfloor heating was designed for low temperatures.
A temperature of 40°C (104°F) with a heat pump generally means roughly double the electricity consumption compared to what would actually be needed. With the current weather, we are running at around 24-27°C (75-81°F) supply temperature. This is only possible if the underfloor heating was designed for low temperatures.
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ludwig88sta17 Dec 2019 11:23boxandroof schrieb:
But if you switch later from gas to a heat pump it would have been better to plan it properly from the start (underfloor heating).Since you are a fan of gas heating. If gas prices are high in 10 years and you switch now to a heat pump, that sounds like a problem. Why?
boxandroof schrieb:
A temperature of 40°C (104°F) with a heat pump roughly means double the electricity consumption compared to what would actually be necessary. With the current weather, we are at about 24-27°C (75-81°F) supply temperature. This is only possible if the underfloor heating was designed for low temperature operation.If I trust our display, we are still feeding in power even in dull weather at the moment... But as I said, we haven’t had a proper commissioning yet, and our installer is still adjusting things, so this can certainly be optimized.
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