ᐅ Y-Tong vs. Concrete Without Additional Insulation in Practice (Heating Costs)
Created on: 28 Feb 2019 17:02
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Keishadow
We are about to start building a house using Ytong blocks without additional insulation, with underfloor heating and a heat pump.
Nevertheless, I am interested in this comparison and roughly how much higher heating costs in percentage terms could be expected, if that can even be calculated.
Energy saving is a big focus nowadays. That’s why Ytong was recommended to us, suggesting that extra insulation might not be necessary. The walls can breathe, and the U-value is sufficient. However, the problem with the U-value is that it is a "laboratory value." In practical situations, the sun shines outside, even in winter! Materials with high density like concrete, calcium silicate blocks, etc., are warmed by the sun and can transfer that heat inside the house. Ytong heats up less strongly but retains the interior heat for longer. The same issue applies to triple-glazed windows. They keep the heat inside better but don’t allow the interior space to warm up as much when the sun shines. This puts the U-value into perspective and makes calculating the actual energy consumption for heating somewhat complicated.
If you also factor in air conditioning, which is used in summer to cool a Ytong house, it gets even more complex. Concrete, on the other hand, could keep the interior cooler in summer, potentially allowing one to avoid air conditioning altogether, which saves energy again.
So, it could well be that the difference in heating costs is not as significant as expected in the end. However, with concrete, you might enjoy significantly more comfortable temperatures during the summer.
Does anyone have experience with this? Perhaps someone lives in a concrete house without insulation and can share insights about the indoor climate and heating costs? I would be really interested to hear what comes out of it...
Nevertheless, I am interested in this comparison and roughly how much higher heating costs in percentage terms could be expected, if that can even be calculated.
Energy saving is a big focus nowadays. That’s why Ytong was recommended to us, suggesting that extra insulation might not be necessary. The walls can breathe, and the U-value is sufficient. However, the problem with the U-value is that it is a "laboratory value." In practical situations, the sun shines outside, even in winter! Materials with high density like concrete, calcium silicate blocks, etc., are warmed by the sun and can transfer that heat inside the house. Ytong heats up less strongly but retains the interior heat for longer. The same issue applies to triple-glazed windows. They keep the heat inside better but don’t allow the interior space to warm up as much when the sun shines. This puts the U-value into perspective and makes calculating the actual energy consumption for heating somewhat complicated.
If you also factor in air conditioning, which is used in summer to cool a Ytong house, it gets even more complex. Concrete, on the other hand, could keep the interior cooler in summer, potentially allowing one to avoid air conditioning altogether, which saves energy again.
So, it could well be that the difference in heating costs is not as significant as expected in the end. However, with concrete, you might enjoy significantly more comfortable temperatures during the summer.
Does anyone have experience with this? Perhaps someone lives in a concrete house without insulation and can share insights about the indoor climate and heating costs? I would be really interested to hear what comes out of it...
Y
yellow_ms1 Mar 2019 10:17Yes, sometimes the tone on construction sites can be quite harsh. But does it really have to be the same way here in the house building forum? A forum is a place to ask questions. Yes, there are sometimes questions that don’t seem very well thought out, or that could maybe be answered with a 5-minute Google search, and so on. But you can still respond in a normal, respectful way, can’t you?
Edit: By the way, I don’t see this question fitting into any of those categories.
Edit: By the way, I don’t see this question fitting into any of those categories.
Keishadow schrieb:
I don’t understand why so many people here are upset or don’t understand the question. It’s simple...
A very straightforward question. Are the heating costs here then twice as high as with a usual KfW55 build? This is a visible facade with insulation in between, which costs a fortune. Buildings without any insulation haven’t been constructed for about 100 years.
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nordanney1 Mar 2019 10:38It doesn’t look like solid construction but rather like a ventilated facade. And yes, insulation is ALWAYS necessary with concrete construction. Either as a sandwich panel (for example, with precast elements; there is a Nordic supplier that only builds this way but is not represented in Germany) or with exterior-applied insulation.
A very simple answer (which you can also figure out yourself): It depends. The same house built with monolithic Ytong or double-layered sand-lime brick with cavity insulation and brick cladding, or however (e.g., concrete) using the same heating technology, will have comparable heating costs if the occupants follow the same heating behavior.
You can also build to KfW 40 standard and still have higher heating costs than a "normal" efficiency house. That then depends on the occupants or the favorable calculation methods used for KfW classifications.
P.S. If you want to invest in the order of €5 million as in your example house, you should rather look for good architects and craftsmen instead of worrying about minor details like €100 more or less in annual heating costs.
Building this way won’t be cheap since you are essentially an enthusiast or niche buyer. Niche buyers typically pay much more. It’s the same with electric cars—they are simply too expensive in terms of price/performance ratio.
Keishadow schrieb:
2. very simple question. Are the heating costs then twice as high as, for example, with the usual KfW55 construction standard?
A very simple answer (which you can also figure out yourself): It depends. The same house built with monolithic Ytong or double-layered sand-lime brick with cavity insulation and brick cladding, or however (e.g., concrete) using the same heating technology, will have comparable heating costs if the occupants follow the same heating behavior.
You can also build to KfW 40 standard and still have higher heating costs than a "normal" efficiency house. That then depends on the occupants or the favorable calculation methods used for KfW classifications.
P.S. If you want to invest in the order of €5 million as in your example house, you should rather look for good architects and craftsmen instead of worrying about minor details like €100 more or less in annual heating costs.
Building this way won’t be cheap since you are essentially an enthusiast or niche buyer. Niche buyers typically pay much more. It’s the same with electric cars—they are simply too expensive in terms of price/performance ratio.
Because today is Friday:
Solar heat gains are indeed lower with triple glazing compared to double or even single glazing. However, the reduced gains are more than compensated by the saved heat losses. In summer, it can even help prevent excessive overheating to some extent.
Concrete alone also heats up very quickly in summer, and the house would warm up rapidly when exposed to sunlight because any heat arriving at the exterior transfers quickly inside. Avoiding air conditioning is possible with intelligent design regardless of concrete. This involves roof overhangs, window orientation and size, and for design mistakes, external shading devices (such as blinds or shutters) are available.
The difference between NO insulation and current new construction standards is substantial, no matter if the building is made of concrete, wood, or clay. Current standards and energy requirements for accessory buildings may be somewhat strict, but a building made purely of concrete is pointless in every respect.
Without asking anyone individually, I’m willing to bet that nobody does. “Modern” living (warm, without mold and frost on the walls) is not possible in a pure concrete structure (above ground). Due to poor thermal protection, the interior walls would be very cold, causing constant condensation from the humidity in the air, which would also freeze in winter. Heating would need to be very high because of this. Additionally, a huge air exchange would be required to remove humidity and minimize condensation, which again leads to higher heating demand. This is clearly seen in old brick buildings without insulation, built with 24cm (10 inches) solid bricks. There you have to ventilate and heat a lot to avoid condensation and mold. To achieve the same thermal protection as 24cm (10 inches) bricks, you would need concrete walls about 70–80cm (28–31 inches) thick—and that still wouldn’t be good.
By the way, concrete is a first-class vapor barrier. It is not diffusion-open; after about 20cm (8 inches) thickness, almost nothing passes through.
As has already been answered: they may have concrete on the outside or inside, but there is always insulation in the middle.
Keishadow schrieb:
The same problem applies to triple-glazed windows. They keep heat inside better, but in the sun, the interior also doesn’t warm up as much.
Solar heat gains are indeed lower with triple glazing compared to double or even single glazing. However, the reduced gains are more than compensated by the saved heat losses. In summer, it can even help prevent excessive overheating to some extent.
Keishadow schrieb:
With concrete, the interior would stay cooler in summer, and you might even be able to skip air conditioning altogether
Concrete alone also heats up very quickly in summer, and the house would warm up rapidly when exposed to sunlight because any heat arriving at the exterior transfers quickly inside. Avoiding air conditioning is possible with intelligent design regardless of concrete. This involves roof overhangs, window orientation and size, and for design mistakes, external shading devices (such as blinds or shutters) are available.
Keishadow schrieb:
So it might well be that in the end the difference in heating costs is not that big
The difference between NO insulation and current new construction standards is substantial, no matter if the building is made of concrete, wood, or clay. Current standards and energy requirements for accessory buildings may be somewhat strict, but a building made purely of concrete is pointless in every respect.
Keishadow schrieb:
? Does anyone here perhaps live in a concrete house without insulation
Without asking anyone individually, I’m willing to bet that nobody does. “Modern” living (warm, without mold and frost on the walls) is not possible in a pure concrete structure (above ground). Due to poor thermal protection, the interior walls would be very cold, causing constant condensation from the humidity in the air, which would also freeze in winter. Heating would need to be very high because of this. Additionally, a huge air exchange would be required to remove humidity and minimize condensation, which again leads to higher heating demand. This is clearly seen in old brick buildings without insulation, built with 24cm (10 inches) solid bricks. There you have to ventilate and heat a lot to avoid condensation and mold. To achieve the same thermal protection as 24cm (10 inches) bricks, you would need concrete walls about 70–80cm (28–31 inches) thick—and that still wouldn’t be good.
Keishadow schrieb:
That’s what diffusion-open means
By the way, concrete is a first-class vapor barrier. It is not diffusion-open; after about 20cm (8 inches) thickness, almost nothing passes through.
Keishadow schrieb:
Or are the exposed concrete houses perhaps made from lightweight concrete?
As has already been answered: they may have concrete on the outside or inside, but there is always insulation in the middle.
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Keishadow1 Mar 2019 12:05nordanney schrieb:
P.S. If you plan to invest around €5 million (about $5.5 million) like in your example house, it’s better to focus on finding good architects and skilled craftsmen rather than worrying about minor details like an extra €100 ($110) in annual heating costs.
Building this way won’t be cheap because you’re essentially creating something unique or custom. Unique builds tend to cost significantly more—it's similar to electric cars, which are also priced higher relative to their performance. The question isn’t whether you can afford it or not. If it costs an extra €200 ($220) per month, that’s manageable. But using more energy means greater environmental impact, which increases proportionally with the energy costs. It might have been possible here that there was a design that, although expensive upfront, saves heating energy in the long run and thus benefits the environment. You never know how advanced technology really is. Besides, the discussion also involved the combination of winter heating and summer air conditioning. But anyway, I consider this thread closed. Decades ago, if someone had claimed you could cut stone with water, no one would have believed it was possible with the right method. You just need to ask questions to get information.
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Keishadow1 Mar 2019 12:07Lumpi_LE schrieb:
This is an exposed facade with insulation in between; it costs a fortune. Completely uninsulated construction hasn’t been done for about 100 years. Cool. Thank you very much! That’s exactly the information I was looking for. So there is something in between after all...
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