Zero-energy Attefall. How would you have done it?

[Ulltand]

I am a trained civil engineer, so I would say I have pretty good knowledge in building physics.

The problems are the same for large and small projects.
A window is not more airtight just because it is installed on a small wall?

But then you should be able to understand that, for example, thermal bridges have a limited impact.

I have simulated the house we are talking about here in BIM-energy. If I remove all thermal bridges completely in the model (which should hardly be possible technically), the transmission losses decrease by about 400 kWh per year. And that can in turn be compensated with 4 sqm of solar panels.

 

[oliven1]

But then you should be able to understand that, for example, thermal bridges have a limited impact.

I have simulated the house we are talking about here in BIM-energy. If I completely remove all thermal bridges in the model (which should hardly be possible building-technically), the transmission losses decrease by about 400 kWh per year.

that's not correct,
thermal bridges have an enormous impact on a building and by enormous, I really mean it.

Go outside on a cold day when it has snowed, and you will understand what an enormous impact thermal bridges have.

 

[Karl-Ove Qvarfordt]

The heat demand per square meter increases the smaller you build. It's the ratio between the envelope area and the floor area that determines it. Then the system losses are also spread over a larger area. Smaller houses still have lower total energy consumption. Energy consumption per square meter or per household?

Per m2 is the established measure as far as I know.

 

[Ulltand]

not true,
thermal bridges have a huge impact on a building and by huge I really mean it.

Go out on a cold day when it has snowed and you will understand what a huge impact thermal bridges have..

BIM energy usually matches well. But I manually recalculated and got 450 kwh so it's accurate.

It's an advantage to have good knowledge of physics. You don't have to guess or be at the mercy of what others say.

 

[fribygg]

unfortunately, you are wrong

If you want to express your own lack of knowledge, I suggest the phrasing 'unfortunately, I am often wrong'

yes, but on the other hand, he shows a log house which would never work

if you build unbroken insulation you get no penetrations that need sealing, thus cold bridges are incredibly important for the tightness.

Do you have trouble with Swedish, or do you just have difficulty writing clearly and understandably?

You write that "cold bridges are incredibly important for tightness," what do you mean by that? Tightness hardly has anything to do with either insulation or potential cold bridges.

am educated as a civil engineer, so I would say I have fairly good knowledge in building physics

You should know the difference between a cold bridge and tightness if you learned anything in your education. I could easily make a new unfinished log frame reasonably tight with building plastic and tape (maybe not to passive house standards) but know from practical experience that it is not a good way to build log houses.

Absolutely, tightness is important, both from an energy and moisture perspective. Then there are many regular houses with taped plastic that also meet the tightness requirements for passive houses.

If you have a bunch of strange penetrations in the wall, it's obviously trickier to seal there, but cold bridges in the form of wall studs that we're talking about now are not a problem for tightness.

A correctly installed and taped building foil is, as far as I know, the easiest way to make a new house tight, but do you think @Johannes Carlsson it is suitable in TS's build, which is primarily intended to be a summer cottage?

 

[Plupp 405730]

The density in a wooden house is twofold, meaning it needs to be wind and water-repellent from the outside to the inside; otherwise, the insulation won't work... The vapor/air tightness from the inside is achieved with a suitable foil for the intended execution...

 

[oliven1]

BIM energy usually matches well. But I manually recalculated and got 450 kWh, so it matches well.

It is an advantage to have good knowledge in physics. You don't have to guess or be at the mercy of what others say.

Yes, but if you don't know building physics, you have no idea about the number of thermal bridges you need to account for, unfortunately. There are a lot of thermal bridges in a conventional building.

 

[fribygg]

The density in a wooden house is two-sided, meaning it needs to be wind and water repellent from the outside in, otherwise the insulation won't work..
The vapor/air tightness from inside is achieved with a suitable foil for the intended design…

Unless you're considering a log house

 

[oliven1]

If you want to express your own lack of knowledge, I suggest the phrasing 'unfortunately, I am often wrong.'



Are you having trouble with Swedish, or do you just have difficulty writing clearly and understandably?

You wrote that "thermal bridges are incredibly important for airtightness"—how do you mean? Airtightness hardly has anything to do with either insulation or potential thermal bridges.

You should know the difference between a thermal bridge and airtightness if you've learned anything in your education. I could easily make a new half-log cabin reasonably airtight with construction plastic and tape (maybe not to passive house standards), but from practical experience, I know it's not a good way to build log houses.

A correctly installed and taped building foil is, as far as I know, the simplest way to make a new house airtight. But do you think, @Johannes Carlsson, that this is suitable for TS's build, which is primarily meant to be a summer house?

Don't really know what you're talking about, but of course, airtightness and uninterrupted insulation go hand in hand.

 

[fribygg]

there are a lot of thermal bridges in a conventional building

In what way do you mean that this is relevant and important for TS?

 

[oliven1]

The density in a wooden house is two-sided, meaning it needs to be wind and water-repellent from the outside in, otherwise, the insulation won't do its job...
The vapor/air tightness from the inside is done with a suitable foil for the intended execution…

easy to just say so but it's how to solve it that is the issue.
wrapping and taping the whole house as usual doesn't achieve passive house standards, not even close.

 

[oliven1]

In what way do you mean this is relevant and important for TS?

if TS wants to build a zero-energy house, it is very relevant if one wants to meet the requirements for it.

 

[Plupp 405730]

If you're not considering a log house

We had a neighbor who built a rough log house as a year-round house, to get the building permit he had to insulate all the outer walls on the inside to meet energy requirements.. then I think much of the feeling of a log house is lost...

 

[oliven1]

We had a neighbor who built a rough log house as a year-round house, to get the building permit he was forced to insulate all the exterior walls on the inside to meet energy requirements.. then I think much of the feeling of a log house disappears...

and that was solely to meet the BBR requirements.
imagine then the enormous compromises one must make if one wants to build a passive house or similar.

 

[Plupp 405730]

and then it was solely to meet the BBR requirements.
imagine the enormous compromises one must make if one wants to build a passive house or similar.

I myself have not seen a single passive house with solid timber walls but I'm sure there's someone who has managed this😉