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

[nybyggarn3]

That's the point of building the fridge into the wall. The insulation on the sides is already in the wall!

The door is like a regular fridge, 6 C on the inside and room temperature on the outside.

The back against the outer wall is the one that provides free cooling from December to April.

During the summer months, there is a good supply of electrical energy from the solar panels on the roof to run the fridge on compressor cooling.

That could be a fun calculation exercise for those who are up to it. I'm not, but I guess you will end up losing because you cool the house more than you save.

A combo fridge with a compressor is definitely out with this solution if you want it cold in the freezer.

 

[Rabbithole]

If you want to make it more sensible, you would place the cabinet in front of the fresh air vent or build a pantry with vents so you can close it.

Fun with passive cooling. But it requires some work to make it good. Hassle to save 100kWh per year.

 

[Genaugenau]

Interesting project and thread!

If we turn the tables and start with a modular house in attefall size with a wood stove and solar panels, how would it hold up "off grid" and how could the performance be optimized without having to design something very complex or custom-made?

 

[z_bumbi]

I would start by drawing in a basement, which is a good solution for saving energy and achieving a stable indoor climate. It also doubles the space.

Then, orient the house with the long sides facing south and north.

Small windows and storage on the north wall.
Large windows on the south wall with an overhanging roof to reduce solar heat in the summer. Preferably an awning that is controlled by temperature and sunlight.

A hedge or permeable fence on the north side and a tree on the east side.

Then start thinking about heating and insulation.

 

[tracker]

Insulation
https://www.bellapanel.se/bellaisopanel/

Ventilation
https://mitsubishielectric.se/produ...zd0eGxvWcePTYsFgoQUwvQB5LCr_MC_BoCCHkQAvD_BwE

 

[Rabbithole]

Getting bad vibes from that site. Maybe just poorly structured. But nothing advanced there. PIR boards with laminated surface layers.

 

[nybyggarn3]

Getting bad vibes from that site. Maybe just poorly structured. But nothing advanced there. PIR boards with glued-on surfaces

Same here. Thought the language was subpar. A bit like it was translated.

The company turned over nine million last year, so they must have sold something. Hardly any larger halls.

 

[fribygg]

If you turn it around and start from a modular house in Attefall size with a wood stove and solar panels, how would it hold up "off grid" and how could the performance be optimized without designing something very complex or custom-made?

If you are not restricted by the Attefall rules regarding height, I think it would be simple to choose a modular/prefab house in the desired size and during assembly add an extra half meter of insulation on the roof. If you have chosen a slab on ground or basement, you can easily add an extra dm of insulation under the concrete floor as well.

 

[Sallader]

I've started considering building a zero-energy house in an Attefall format. A lot of floor space would disappear with 50 cm wall insulation, but perhaps 20 sqm would remain inside and then a 10 sqm loft. The roof could be a shed roof with integrated solar panels. Roof insulation could be a problem with the limited building height if you want a loft? With windows having u-values down to 0.7, one should be able to achieve a bright building that doesn't need much electricity for lighting. The heat source in such a small house would probably be best with a LLVP. Demand-controlled ventilation of the unusual format that switches between supply and exhaust air in the same channel with storage media for heat energy. You'd want a fireplace if you have a plot with lots of trees, but I suppose you can't include that in the calculation?

PU foam insulation? 😅 Just insulated our Attefall house with it 👍 Have 120 studs 10-11 cm insulation in walls and roof.

 

[oliven1]

Haven't read the whole thread but it seems like many are giving advice on different material choices, etc. However, I've built a lot of passive houses over the years. The most important thing is how you design them, paying attention to every little detail. Then you can use regular building materials like mineral wool, timber frames, and so on.

Avoid geometric thermal bridges, recessed beams, continuous insulation layers, round shapes, build walls in multiple layers separate from each other, as few windows as possible to only meet requirements, windows recessed in the facade. Extremely careful with the plastic, collars and tape everywhere, pressurize before installing boards, no balconies or similar, slotted studs, correct corner constructions (rarely done), over-insulate frames, raise the eave, separate edge beam from the base plate, frost insulation, always use intermittent fixings, large roof overhangs, heat recovery, solar energy preferably hybrid energy, airlocks.

Again, the plastic/tightness is extremely important, can't stress that enough.

Also, one should know it's not just advantages to living in a passive house. There are many disadvantages that you should be aware of, and it certainly doesn't suit everyone.

Then it seems like many people don't know what a passive house is, it doesn't mean it consumes zero? Instead, a passive house is a standard in Europe that is clearly defined with several parameters so that a building can be certified.

For example:
Climate zone 3: 30 kWh/m2
U-value max: 0.9 W/m2C°
Tightness requirements: max 0.3 l/s and m2
etc...

 

[fribygg]

Haven't read through the entire thread, but it seems like many are advising on different material choices, etc.
But I have built many passivehouses over the years.

avoid geometric thermal bridges, recessed floors, continuous insulation layers,

Hello and welcome to the forum @oliven1
I recommend that you read through the thread, or at least the thread start and the OP's own posts. If you do that, you will see that it is a Zero Energy House with traditional heating that the OP is considering, not a passive house.

Unlike oliven1, I would recommend continuous insulation layers; it's a good and simple way to reduce thermal bridges.

 

[oliven1]

Hello and welcome to the forum @oliven1
I recommend that you read through the thread, or at least the thread start and TS's own posts, if you do that you'll see that it's a Zero-energy house with traditional heating that TS is considering, not a passive house.

I would, unlike oliven1, recommend continuous insulation layers, it's a good and simple way to reduce thermal bridges.

What?

If you're going to build zero-energy or plus-energy houses, it's even more important to build according to what I wrote.

I explicitly wrote that you should have continuous insulation layers, I even wrote it a couple of times.

 

[fribygg]

avoid geometric thermal bridges, recessed floor slabs, continuous insulation layers,

Maybe you just worded it a little poorly?

 

[Rabbithole]

Well, it's not that critical. A low-rise building with solar panels will easily become energy-positive.

But I agree otherwise that it is important to construct a well-thought-out building envelope with minimal thermal bridges.

 

[oliven1]

You might have just phrased it a bit poorly?

possible, meant clearly one thing at a time.
But tried to write a little quickly.

it's not like you should avoid recessed beams?
then I also wrote continuous insulation layers and building walls in multiple layers separated from each other.