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.
B
boxandroof17 Dec 2019 16:46HVAC planner, but that costs money. Otherwise, study the knowledge yourself (specialist forums on building services engineering, including some good posts here in this forum for some time now) and work together with skilled craftsmen. They can definitely handle it if you give them some guidelines.
Plan the underfloor heating with a maximum supply temperature of 30-32°C (86-90°F) based on room-by-room heat load calculations. All circuits about 80 meters (260 feet), maximum 100 meters (330 feet). Avoid very small circuits. If you manage this early on, you are on a good path.
Heat pump without a buffer tank.
Plan the underfloor heating with a maximum supply temperature of 30-32°C (86-90°F) based on room-by-room heat load calculations. All circuits about 80 meters (260 feet), maximum 100 meters (330 feet). Avoid very small circuits. If you manage this early on, you are on a good path.
Heat pump without a buffer tank.
L
ludwig88sta17 Dec 2019 19:02Thank you. But I find it surprising that the heating engineer is not familiar with these "standards." They also want to maintain a good reputation, ensuring customers are satisfied and recommend them further. He should be well-versed in this subject.
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boxandroof17 Dec 2019 19:12Heating engineers (HBs) are often hired by general contractors (GCs), where reputation matters less and the focus is on low cost. They tend to provide quick estimates and minimize pipe lengths.
The heating engineer I hired was very competent; I provided him with plans and was able to discuss them thoroughly. However, I don’t know how he would have designed the system on his own initiative.
If the manufacturer states that a buffer tank is mandatory, the heating engineer will install it accordingly—unless you specifically request otherwise.
When building, it doesn’t help to be surprised by anything.
The heating engineer I hired was very competent; I provided him with plans and was able to discuss them thoroughly. However, I don’t know how he would have designed the system on his own initiative.
If the manufacturer states that a buffer tank is mandatory, the heating engineer will install it accordingly—unless you specifically request otherwise.
When building, it doesn’t help to be surprised by anything.
L
ludwig88sta17 Dec 2019 19:24boxandroof schrieb:
And if the manufacturer states that a buffer tank is mandatory, the heating installer will install it accordingly—unless you specifically request otherwise.
A buffer tank only makes sense with a conventional heating system, not with purely underfloor heating. Well, the general contractor basically wants to sell their contracted equipment, and the uninformed homeowner or buyer ends up with the buffer tank anyway...
I understand.
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boxandroof17 Dec 2019 19:43The heat pump manufacturers sometimes require this. It is understandable to some extent because individual room control is mandatory (Energy Saving Regulation).
Heat pumps need a certain flow rate, which is incompatible with individual room control. When all thermostats are closed, the heat pump can charge the buffer tank. An alternative to the buffer tank are bypass valves, which should also be avoided or closed when the individual room control is removed. For the heating installer, it is also easier: with an overheated buffer tank and individual room control, the occupants can continue to adjust the thermostats as usual. It becomes warm, and everyone is happy for the time being.
Heat pumps need a certain flow rate, which is incompatible with individual room control. When all thermostats are closed, the heat pump can charge the buffer tank. An alternative to the buffer tank are bypass valves, which should also be avoided or closed when the individual room control is removed. For the heating installer, it is also easier: with an overheated buffer tank and individual room control, the occupants can continue to adjust the thermostats as usual. It becomes warm, and everyone is happy for the time being.
The heating specialists are very familiar with gas because it is a well-known technology that has been used for decades. However, if someone now tries to simply replace heat source 1 (gas) with heat source 2 (heat pump), that’s when the whole drama begins. That was our impression!
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