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

[August.E]

When it comes to ftx, the maximum flows are also specified, without knowledge of the efficiency at lower flows, it is possible to reduce the speed of the motor significantly. This provides both quiet operation and the ability to boost ventilation during showering or cooking.

 

[MagicFingers]

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I have looked at Pax Eos FTX in connection with Attefall houses. However, I have no practical experience with it, but on paper, it seems appropriately sized. The systems with ceramic batteries and alternating air direction I've heard don't work so well and would also require two of them in a bathroom, which makes the cost quite high.

I have also recommended Eos to Attefall builders, then whether they install them or not...

and I also have a contact who installed 2 Blueberg (or a similar name) mini FTX...., the alternative was no ventilation in a tight house... so yes... it does provide a little fresh air and it should retain some heat energy... so.. better than nothing in my opinion.

 

[Robert-san01]

I have an EOS in the garage. I wouldn't exactly recommend it for a small residential building as it makes quite a bit of noise. Better with something like a small combination unit, like the kind typically found in kitchen fans.

The function of the EOS unit is otherwise very good!

 

[nybyggarn3]

I would not insulate 50 cm in the walls. We have 32 cm in our house of just over 160 m2 and the energy consumption for heating is about 4000 kWh per year. Admittedly with geothermal heating but in northern Sweden.

If for some reason you were to take it to the extreme, I would (as already pointed out) look for alternative materials.

 

[Rabbithole]

I wouldn't insulate 50 cm in the walls. We have 32 cm in our house of just over 160 m2 and the energy consumption for heating is about 4000 kWh per year. Certainly with geothermal heating but in northern Sweden.

If for some reason you want to go to extremes, I would (as already pointed out) look at alternative materials.

It should be in proportion to the cost. PIR boards are more expensive than the equivalent insulation value with glass wool.

I have 50cm walls with isocell loose fill, works excellently.

 

[nybyggarn3]

It should be in proportion to the cost. PIR boards are more expensive than the equivalent insulation value with glass wool.

I have 50cm walls with isocell loose fill, works excellently.

Is it some variant of Cellulose? In that case, we have a similar solution, but different thickness.

Besides the cost, you also have to consider how much living space is left. You may have to calculate it, but I find it hard to justify 50 cm when building a tiny house.

 

[Ulltand]

One could build a pantry/fridge into the insulation on the north side. Free cooling from December to April.

The fridge would have the evaporator side on the side to take full advantage of the free cooling from the facade side back.

Regulation issues exist but are solvable. How best to solve them?

 

[Rabbithole]

Is it some variant of cellulose? In that case, we have a similar solution, but different thickness.

Besides the cost, you must consider how much living space remains. You might need to calculate it, but I find it hard to see that 50 cm can be justified when building an attefall house.

Cellulose, recycled newspaper

On attefall houses, never. But if it's just a cabin without space limitations

 

[Rabbithole]

One could build a pantry/fridge into the insulation on the north side. Free cooling from December to April.

The fridge should have the evaporator side on the side to fully utilize the free cooling from the façade at the back.

There are regulatory issues but they are solvable. What is the best way to solve them?

Place a cabinet outside the door instead of creating thermal bridges.
A fridge/freezer consumes under 200kWh per year.

 

[Ulltand]

Place a cabinet outside the door instead of creating thermal bridges.
A fridge/freezer uses less than 200kWh per year

It's impractical to have the fridge outside

And there won't be thermal bridges if you build it like I said. Full insulation in the fridge door.

 

[nybyggarn3]

Cellulose, recycled newspaper

In attefallshus never. But if it's just a cabin without a limit on the area size, that is.

Interesting. Then we probably have exactly the same insulation.

Can you really save a lot of money on the last twenty centimeters in the wall? I get the impression that a large part of our 4000 kWh escapes upwards, downwards, through windows and ventilation.

 

[nybyggarn3]

It is impractical to have the refrigerator outside

And there will be no thermal bridges if you build this as I said. Full insulation in the refrigerator door.

Shouldn't the house be connected to the power grid?

 

[Rabbithole]

Interesting. Then we probably have exactly the same insulation.

Can you really save a lot of money on the last twenty centimeters in the wall? I have a feeling that a large part of our 4000 kWh goes up, down, through windows, and ventilation.

The heat pump has a COP of at least 4, so that's around 16000 kWh in energy leakage.

My walls are built with lightweight beams, so there's a 15 cm thicker masonite board, and more blown-in insulation. Not dramatically more expensive.

Windows absolutely matter, and the roof and floor should correspond to the wall. Then small things like draught excluders around doors contribute a bit. Well-insulated houses can also have lower interior temperatures while maintaining comfort.

 

[Rabbithole]

It's impractical to have the fridge outside

And there will be no thermal bridges if you build this as I said. Full insulation in the refrigerator door.

Absolutely, but it feels like asking for trouble. Don't complicate it.

 

[nybyggarn3]

The heat pump has a COP of at least 4, so that's about 16000kWh in energy leakage.

My walls are built with light beams so there's an additional 15cm thick masonite board, and more loose wool. Not dramatically more expensive.

Windows definitely matter, the roof and floor should be equivalent to the wall.
Then small things like draft stoppers around doors and such make a difference.
Well-insulated houses can also have lower indoor temperatures while maintaining comfort.

Nice to hear. We also built with light beams, but 300mm. Fantastic system and also affordable.

16000 sounds like more but the question is how much would be saved with an additional 20 cm in the walls. It’s rare to heat with direct electricity nowadays. Air-to-air might be reasonable in a tiny house. If there's electricity, that is.

I guess that TS could save a few hundred kWh per year by increasing insulation from 300 to 500 mm. But someone who is competent in that area is welcome to calculate it.

But otherwise, I think you have a good concept