ᐅ Self-Managed Construction Project: Simple Single-Family Home
Created on: 22 May 2016 18:40
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theoretikerT
theoretiker22 May 2016 18:40Hello, we are planning to build a single-family house on our own......
Planned size 150 sqm (1,615 sq ft) without a basement, gable roof with raised knee wall.
To achieve KfW 55 standard, my understanding is that a U-value of 0.20 is required. How can I most cost-effectively achieve this with a single-layer wall of 365mm (14 inches) thickness? Noise protection can largely be neglected.
Regards from Franconia
Planned size 150 sqm (1,615 sq ft) without a basement, gable roof with raised knee wall.
To achieve KfW 55 standard, my understanding is that a U-value of 0.20 is required. How can I most cost-effectively achieve this with a single-layer wall of 365mm (14 inches) thickness? Noise protection can largely be neglected.
Regards from Franconia
Hello,
I used 36cm (14 inches) aerated concrete blocks with a thermal conductivity of 0.07 for the exterior walls. For me, this was the ideal block. It is easy to work with (I’m a self-builder), and I constructed all the interior walls with 24cm (9.5 inches) sand-lime bricks.
The roof insulation consists of 120mm (4.7 inches) PUR foam on a shed roof with a 6° pitch.
Under the foundation slab, there is a 50cm (20 inches) layer of glass foam gravel (no basement).
I would definitely build this way again.
My calculated annual energy consumption is about 40 kWh per square meter.
Best regards from Middle Franconia
Thomas
I used 36cm (14 inches) aerated concrete blocks with a thermal conductivity of 0.07 for the exterior walls. For me, this was the ideal block. It is easy to work with (I’m a self-builder), and I constructed all the interior walls with 24cm (9.5 inches) sand-lime bricks.
The roof insulation consists of 120mm (4.7 inches) PUR foam on a shed roof with a 6° pitch.
Under the foundation slab, there is a 50cm (20 inches) layer of glass foam gravel (no basement).
I would definitely build this way again.
My calculated annual energy consumption is about 40 kWh per square meter.
Best regards from Middle Franconia
Thomas
T
theoretiker22 May 2016 20:08Would a 0.08 W/(m²·K) thermal transmittance value including plaster be sufficient for KfW 55 standard?
Well, the bricks are just one part of the whole picture. Everything has to work together.
Since I am building without financing, I don’t care about the ‘KfW value’. However, I want to keep heating costs as low as possible, so I pay close attention to that. The building envelope is only one factor. There are other aspects like ventilation, heating, etc., that also influence the primary energy demand in the end.
Thinking ‘I use this or that brick and then I get KfW-55’ is the wrong approach!
There are many ways to achieve KfW standards. You either need to find a professional to support you or invest A LOT of time. Ultimately, if you need the certification, you will have to hire someone to officially confirm everything.
Best regards,
Thomas
Since I am building without financing, I don’t care about the ‘KfW value’. However, I want to keep heating costs as low as possible, so I pay close attention to that. The building envelope is only one factor. There are other aspects like ventilation, heating, etc., that also influence the primary energy demand in the end.
Thinking ‘I use this or that brick and then I get KfW-55’ is the wrong approach!
There are many ways to achieve KfW standards. You either need to find a professional to support you or invest A LOT of time. Ultimately, if you need the certification, you will have to hire someone to officially confirm everything.
Best regards,
Thomas
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nightdancer23 May 2016 08:40theoretiker schrieb:
Hello, we are planning to build a detached house on our own.......
Bold, I must say.
I would recommend adding at least one professional to inspect the construction, airtightness, thermal bridges, building defects, workmanship, and so on.
Otherwise, good luck!
The Energy Saving Ordinance (Energieeinsparverordnung), which is also used to calculate the so-called KfW rating, roughly speaking, takes into account two parameters.
1) Transmission heat loss: (heat lost through the building envelope)
A metaphor for building defects: (compare this to a person wearing a thick jacket in winter.)
If this person wears a thick jacket and is well bundled up, they won’t feel cold. However, if they don’t wear a scarf and the jacket is not windproof at the waist, the thickest jacket won’t help and they may freeze. It’s the same if the jacket is wet (keyword: dew point...).
2) Primary energy demand: (this depends on the heating system)
With a less well-insulated house but equipped with an ecological heating system (renewable raw materials/renewable energy), it is still possible to achieve a good KfW rating.
Other factors included in the calculation are, for example, the size of glazed areas, presence of a conservatory/sunroom, the shape of the floor plan, building orientation...
Otherwise, good luck!
The Energy Saving Ordinance (Energieeinsparverordnung), which is also used to calculate the so-called KfW rating, roughly speaking, takes into account two parameters.
1) Transmission heat loss: (heat lost through the building envelope)
A metaphor for building defects: (compare this to a person wearing a thick jacket in winter.)
If this person wears a thick jacket and is well bundled up, they won’t feel cold. However, if they don’t wear a scarf and the jacket is not windproof at the waist, the thickest jacket won’t help and they may freeze. It’s the same if the jacket is wet (keyword: dew point...).
2) Primary energy demand: (this depends on the heating system)
With a less well-insulated house but equipped with an ecological heating system (renewable raw materials/renewable energy), it is still possible to achieve a good KfW rating.
Other factors included in the calculation are, for example, the size of glazed areas, presence of a conservatory/sunroom, the shape of the floor plan, building orientation...
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