Passive house project: discussions and details

[gui42]

Bonjour à tous

It's decided, I want to build a house, and as long as done, passive (with some options for saving water, solar panels, and various ideas of my own).
Since I am not in a hurry, I really want to try to calculate as many things as possible and a helping hand will not be too much. This is the reason for this topic. It is therefore a question of briefly recalling the principles of a passive house (there are already several sites dealing with this), but above all then of studying the stages of construction and deciding on the options - techniques, materials. .

Definition:
A house is passive when the total energy needs do not exceed 50 kWh / m² / year. This means that there is almost no need for heating.

The main principles of a passive house:
1) It is first of all a bioclimatic house, that is to say that its design (in particular the organization of the rooms and the use of glazed area to the south), makes it possible to maximize the energy inputs by the sun, and that it has a good inertia to retain these contributions.
2) As we have benefited from solar energy, we especially do not want to lose it. Therefore :
- the insulation is very high
- thermal bridges excluded
- the controlled air flows (the house must be waterproof apart from the VMC which will be double flow with heat exchanger).
So we can see that a lot of thinking will be required on the plan (orientation), the choice of construction materials, the way of building, the insulation and therefore the windows, the CMV.

Reference sites:
Definitions by Wikipedia et Ekopedia.
The project supported by the EU: Passive-On and the French label Effinergy.
The "reference" sites: MP en, Pm be, the MP be, C. Lehr's website.
Examples : Linotte, MP in Nice, MP in the Ardennes.

The stages to study: (a little according to the order given on House ideas)
1) the budget: € 165000 (land + house), I'm looking for examples of construction costs.
2) the terrain: we will look for the orientation, the maximum slope, the clearance ...
3) the specifications: we will start by studying particular points to define specifications or even a checklist that the plans will have to "undergo".
3) the plan: we will propose plans ...
4) professionals: I cannot build everything alone for lack of skills, but I want to participate. On the other hand, large manufacturers this will not be possible given the technical requirements.

The options and my personal ideas:
We will talk (in step 3) of solar (DHW and PV), rainwater recovery and filtration, Canadian well, heat recovery in the shower (!?!).


With that, I must point out that I am most often absent during the week (I work on the move), so it may not always change very quickly.
To me to play!

[Christophe]

Very good initiative, I wish you good luck in your approach!

There is already a topic on passive house: https://www.econologie.com/forums/maison-passive-t1471.html and here is a complete example of a passive house http://passive-aventure.vivao.be/index.php (but it lacks a bit of technical details I think ...)

[jean63]

It is clear that at the "cost" level, it should not be given.

30 to 80 cms of insulation in the walls !!!! I already have 15 cms + wooden frame + wooden cladding (thickness = 2 cms) ==> it gives a very good coefficient. insulation already !! in 1983, when I built it was very much above the maximum insulation practiced at the time.

Triple glazing ; it should not be given especially on large bay windows and then you need an oversized window frame or window to receive these very thick triple glazing which are very heavy. I remember the price of my 2 large bay windows of 2m X 3m in wood + double glazing, it was already COPIOUS.

VMC dual streams, that's great, but it takes electricity to run the fan motor (which runs day and night non-stop). Other than that it is ideal for the renewal of air in the house. There it is more than essential with the enormous insulation.

In my opinion, it is a type of house that presents a significant additional cost during construction, that young people who borrow over 30 or 35 years cannot necessarily afford.

So they insulate according to the standard required for traditional electric heating (I see practically all the new houses that are being built are electrically heated in the neighborhood) hence ==> nuclear power plants ... that's the real reality.

What determines the choice of construction is also the available budget. I remember, when I built, I had for 100 Francs (000 euros) of city gas boiler + automatic regilatioon + underfloor heating (circulation of water) low temperature + radiators upstairs.

The advantage is that I can connect all the means of hot water production to supply this type of heating (solar collectors, wood pellet boilers, .PAC water-water ... etc. Remains to be seen evolution of gas prices and subsidies granted for renewable energies .......... to follow.

[Targol]

30 to 80 cms of insulation in the walls !!!! I already have 15 cms + wooden frame + wooden cladding (thickness = 2 cms) ==> it gives a very good coefficient. insulation already !! in 1983, when I built it was very much above the maximum insulation practiced at the time.

Good insulation is indeed essential. Now, the position (inside or outside of load-bearing structures with high thermal inertia) of this insulation is also (see more important) than its thickness. For your information, I would like to remind you that the effectiveness of an insulation is far from being proportional to its thickness, as shown by the graph below:


We see that the 2 cm to go from 2 to 4 cm of insulation save 12l / m2 of fuel oil while the 2cm to go from 28 to 30cm only gain 0,2l / m2.
It is therefore necessary to find, depending on the climate where the house will be located, the right thickness / price ratio.

Likewise, it is important to look at ALL the characteristics of the insulation. Thus, certain insulators are effective in winter but little in summer (mineral wool, for example).

Triple glazing ; it should not be given especially on large bay windows and then you need an oversized window frame or window to receive these very thick triple glazing which are very heavy. I remember the price of my 2 large bay windows of 2m X 3m in wood + double glazing, it was already COPIOUS.

I totally agree with you, Jean. Not only is it heavy and expensive, but, depending on the climate of the location of the house, it can also be less interesting than double glazing with low emissivity (at least for the southern facades, the northern facades not being, ideally, no breakthroughs). I would remind you that the more layers of glass there are, the less light and thermal radiation pass through, which reduces the greenhouse effect in the house, the main heating vector for a passive house.

VMC dual streams, that's great, but it takes electricity to run the fan motor (which runs day and night non-stop). Other than that it is ideal for the renewal of air in the house. There it is more than essential with the enormous insulation.

Not quite agree on this point there: in my opinion, a VMC double flow can advantageously be replaced by the conjunction of a Canadian well and a ventilation by natural convection (the fresh air returns to the ground by the Canadian well and comes out through openings on the roof). This solution has the advantage of not consuming electricity if the ventilator of the Canadian well works on photovoltaic sensors (the ventilation during only the day is sufficient, no need of 24h / 24h).

[jean63]

Not quite agree on this point there: in my opinion, a VMC double flow can advantageously be replaced by the conjunction of a Canadian well and a ventilation by natural convection (the fresh air returns to the ground by the Canadian well and comes out through openings on the roof). This solution has the advantage of not consuming electricity if the ventilator of the Canadian well works on photovoltaic sensors (the ventilation during only the day is sufficient, no need of 24h / 24h).

OK ..... the Canadian well I like it as a system: the problem is that it digs 1,50 m in its ground. In my case I have either the buried electricity supply, in another place it is the water supply and in gas + the roots of trees and shrubs (I have a lot on my land to absorb the CO2 that I emit with boiler + vehicles ), so I would have to go under these sheaths but hey it must be doable.

What do you need as a pipe diameter (PVC?)? 10 cms? and as a buried length?

By the way, why the text appears here in large width; I have a 17 "screen.

[Targol]

OK ..... the Canadian well I like it as a system: the problem is that it digs 1,50 m in its ground. In my case I have either the buried electricity supply, in another place it is the water supply and in gas + the roots of trees and shrubs (I have a lot on my land to absorb the CO2 that I emit with boiler + vehicles ), so I would have to go under these sheaths but hey it must be doable.

What do you need as a pipe diameter (PVC?)? 10 cms? and as a buried length?

You will find all the details here

By the way, why the text appears here in large width; I have a 17 "screen.

It is only due to the large size of the graph that I inserted.

[jean63]

Thanks Targol

The problem with us in Auvergne is that because we are almost at the top of the range (105 to 150 bq / m2):
Beware of radon
Radon is a radioactive gas found naturally in the soil. It results from the transformation of elements such as Uranium 238, radium 226 etc.
Radon is dangerous if inhaled. In the short or long term, it can cause cancer. A map of France has been drawn up in order to highlight the most exposed French regions, this is linked to the nature of the soil.

The Canadian well must therefore be perfectly watertight in its buried part, but we must not forget that this gas can seep into crawl spaces and into the home by taking advantage of an unsealed slab or cracks. Hence the importance of ventilation.

Although taking care to properly glue the tubes constituting the Canadian well so as not to bring radon gas into the house, that is doubtful. There is also the risk of condensation, while currently my house is perfectly healthy (no mold area probably linked to the wooden structure and the well-drained land naturally).

I still have to take care of my ventilation because I don't have VMC, that's why I like the "double flow" (I knew it then I tried to operate without anything - opening of windows from time to time - and thanks to the fact that there is wood everywhere, the humidity is regulated with wood).

I'm going to think about the Canadian well, there must be Auvergnats who made it.

PS: by the way how did you do to put this graphic on the page. I have the same thing to do with photocopies (scanner) of an article published in Auto-Moto ?. thank you.

[Targol]

PS: by the way how did you do to put this graphic on the page. I have the same thing to do with photocopies (scanner) of an article published in Auto-Moto ?. thank you.

Christophe made a POST on this subject.

[zac]

This solution has the advantage of not consuming electricity if the ventilator of the Canadian well works on photovoltaic sensors (ventilation during only the day is sufficient, no need of 24h / 24h).

Hello

a well-designed Canadian then doesn't need a fan

@+

[jean63]

PS: by the way how did you do to put this graphic on the page. I have the same thing to do with photocopies (scanner) of an article published in Auto-Moto ?. thank you.

Christophe made a POST on this subject.

OK thank you for the info ......... I missed episodes during my absence from forum.