Victory is ours!

[Garald]

This is not really an introduction, but I didn't formally introduce myself when I got into buildhub more than a year ago.

 

Work is basically done, and it's now official: my place has gone from having an energy rating of F to having an energy rating of B!

 

In particular, this counts as "bâtiment basse consommation en rénovation". French energy rating is insanely hard; of the roughly sixty places I visited when I was buying, only two had a B - one was new, and the other one had town heating (still a rarity) due to being next to an incinerator.

 

This is just to say that I am very, very grateful to everybody who helped here. I don't know what I would have done otherwise.

 

The diagnostician's only recommendations are:

- to install MVHR (not sure that's feasible in a house from 1930?)

- to check on airtightness (I'll borrow a thermal imagining camera once it gets seriously cold - is there anything else I should do?).

 

When asked, he also said that installing solar panels and hooking them up to hot water generation could be interesting. (Local peculiarities: it's sunny only in summer, and it is no longer possible to sell excess electricity back to the State.)

 

Thank you again!

[SteamyTea]

14 minutes ago, Garald said:

is there anything else I should do

Make/borrow a pressure tester.

 

15 minutes ago, Garald said:

Local peculiarities: it's sunny only in summer

PV only needs light, not direct sunlight.

[Mike]

Congratulations - that's impressive in the French system!

 

19 minutes ago, Garald said:

to install MVHR (not sure that's feasible in a house from 1930?)

I'm installing MVHR in an 1840s apartment, also in France, so it certainly can be done.

 

My renovation is projected to score a C for energy use & A for CO2 emissions. In the absence of anywhere to install any renewables, that's the highest I can score.

 

Edited November 24, 2023 by Mike

[Garald]

1 minute ago, Mike said:

Congratulations - that's impressive in the French system!

 

I'm installing in an 1840s apartment, also in France, so it certainly can be done.

 

Ah wow. I already have VMI - can both be combined? (I'd think VMI is a good idea even just for its filtering effect - Paris air is not the best.)

 

1 minute ago, Mike said:

 

My renovation is projected to score a C for energy use & A for CO2 emissions. In the absence of anywhere to install any renewables, that's the highest I can score.

 

Ah, you don't have a courtyard to install a heat-pump in? I also got an A for CO2 emissions.

[Garald]

5 minutes ago, SteamyTea said:

Make/borrow a pressure tester.

 

Explain?

[SteamyTea]

A pressure tester is only a relatively small fan stuck in a doorway or window.

Someone on here made there own recently, I think it may have been @Sparrowhawk

[Mike]

2 minutes ago, Garald said:

Ah, you don't have a courtyard to install a heat-pump in?

More of a lightwell than a courtyard and, as it's in a historic area, it would need planning permission as a modification to the 'external appearance' - unlikely, even if I could get it approved by the copropriété AGM.

[Mike]

13 minutes ago, Garald said:

I already have VMI - can both be combined? (I'd think VMI is a good idea even just for its filtering effect - Paris air is not the best.)

If the ducts are the right size you might be able to upgrade, rather than starting from scratch. I'm adding a filter box to mine so that I can add a carbon filter if needed, in addition to a regular G4 air filter to remove the dust.

[Sparrowhawk]

7 minutes ago, SteamyTea said:

A pressure tester is only a relatively small fan stuck in a doorway or window.

Someone on here made there own recently, I think it may have been @Sparrowhawk

Indeed I did.

 

 

 

[Garald]

3 hours ago, Sparrowhawk said:

Indeed I did.

 

 

 

Interesting. Explain what to do with it?

[Sparrowhawk]

11 hours ago, Garald said:

Interesting. Explain what to do with it?

 

First, my house isn't airtight so I check airtightness room by room, but you could do the same putting the fan in an external doorway or window and doing the whole house at once.

 

What I do first bring a bowl of cold water, sharpie (marker pen), dust mask and eye protection into the room (I'm sensitive to dust).

 

Then I put my "blower door" into the room's doorway and seal the gaps at the side with masking tape.

 

I put on the PPE, turn the fan on and go round the room feeling for big draughts. If it's a room I'm going to redecorate I mark where the draughts are on the wall/floor. Otherwise I use post-it notes or similar.

 

I seal these up. With mortar if they're big, or expanding foam if no alternative, or sealant if they're small. Or I stuff insulation material in if they're tricky to get to any other way.

 

Then I wet my hand and go round using the front/back of the hand to trace where the smaller air leaks are. They can be a pain to track down because of the way air flows - where you feel a draught may be caused by a leak half a metre away, instead of where you're feeling it.

 

And then I seal them.

 

It's a slow job but satisfying.

 

The biggest pain point is forgetting to bring something into the room before I tape the door in the door frame. E.g. the sealant gun. That's why in my video it isn't sealed - the room is airtight enough now that the gap round the blower door doesn't matter, and that lets me get in and out of the room easily.

 

I have also used https://www.soudal.co.uk/pro/products/coatings/air-and-vapourtight-coatings/soudatight-lq, a cheaper alternative to Blowerproof or PassivePurple to seal around my joist ends under the floor. I applied it half the thickness it said so we'll see how long it lasts.

Edited November 25, 2023 by Sparrowhawk

[ProDave]

I did similar, a blower door on the door through to the garage, sucking air out of the house.

 

 

It was very crude, big bits of cardboard, some duct tape, and old office desk fan and some strips of wood to support the fan.

 

With the fan extracting air from the house, you can go round feeling or listening for any signs of air coming in.

 

Also once the fan has been running for a while, a good test is to go and open a window or a door, if you are reasonably air tight, you will get a big whooosh of air enter as you open the door ow window showing the house had depresurised.

 

Getting an actual measure of air tightness would be nigh on impossible as nothing is calibrated, but it gives you an idea of any air leaks you might have.

[SteamyTea]

5 hours ago, Sparrowhawk said:

What I do first bring a bowl of cold water

 

5 hours ago, Sparrowhawk said:

Then I wet my hand and go round using the front/back of the hand to trace where the smaller air leaks are

That is a (expletive deleted)ing brilliant idea.

 

5 hours ago, Sparrowhawk said:

The biggest pain point is forgetting to bring something into the room

Take up smoking. Will help find leaks as well.

[joe90]

@SteamyTea and I used joss sticks on my build.

[Garald]

On 25/11/2023 at 17:33, joe90 said:

@SteamyTea and I used joss sticks on my build.

But how would that work? Yes, smoking the entire atmosphere (minus your house) would work, but I take that's not an option.

[Garald]

On 25/11/2023 at 13:04, ProDave said:

I did similar, a blower door on the door through to the garage, sucking air out of the house.

 

 

It was very crude, big bits of cardboard, some duct tape, and old office desk fan and some strips of wood to support the fan.

 

With the fan extracting air from the house, you can go round feeling or listening for any signs of air coming in.

 

I'm really ignorant: how does one set things up so that the fan extracts air rather than pull air in? Also, should I turn the PIV off first?

[joe90]

4 hours ago, Garald said:

But how would that work?

Depressurise the house then wave a joss stick around junctions to detect draughts.

Edited November 28, 2023 by joe90

[Garald]

Daughter? Is she the joss stick provider?

[joe90]

2 minutes ago, Garald said:

Daughter? Is she the joss stick provider?

Bloody spell check, too early for me yet 🤪 (edited)

[Garald]

More seriously: I have a cat flap in the door in front of the little staircase going up to the attic. Could I try to depressurize the attic simply by taping a fan to the open cat flap (presumably on the staircase size), or is the scale off? How powerful a fan do I need?

 

Also: how does the fan know which side to depressurize?

Edited November 28, 2023 by Garald

[SteamyTea]

6 minutes ago, Garald said:

Could I try to depressurize the attic simply by taping a fan to the open cat flap

Yes, and a good place to try it.

6 minutes ago, Garald said:

how does the fan know which side to depressurize

I am smiling as I type this.  You academics.

You turn the fan around so that it is blowing air out the house.

In geometry, I think they call it translation, by 180°.  As a fan is, in effect, a circle, the axis does not matter.

 

Edited November 28, 2023 by SteamyTea

[Garald]

I think these two 2-second videos give you a fair idea of how cat flap, staircase and attic are laid out.

[Garald]

Just now, SteamyTea said:

Yes, and a good place to try it.

I am smiling as I type this.  You academics.

You turn the fan around so that it is blowing air out the house.

In geometry, I think they call it translation, by 180°.

 

*Rotation*.

[SteamyTea]

Just now, Garald said:

Rotation

Yes

[Garald]

On 24/11/2023 at 19:51, Mike said:

More of a lightwell than a courtyard and, as it's in a historic area, it would need planning permission as a modification to the 'external appearance' - unlikely, even if I could get it approved by the copropriété AGM.

I am also in a historic area, and had to ask for planning permission to install awnings - and it was granted. Of course this is just the couronne rouge - things may be different in the 5th.