Mike

In addition to dMEVs, there are also dMVHR units that recover a useful proportion of the outgoing warmth - although, of course, they cost more. If you've not come across that option, do a search and you'll find several discussions.

If you have the budget, choose one from the list at https://database.passivehouse.com/en/components/list/ventilation_small. These units are independently tested to more accurate standards than normal (a higher efficiency ratio = better economy). Also size the unit so that it never needs to run at more than 2/3 capacity.

FWIW, French regulations specify a maximum of 250mm between pipes - more here:

When I studied construction - when there were very few building physics geeks - the library had a whole bookcase documenting experimental buildings technologies that people had tried in an attempt to live off grid or cut their energy bills (carbon emissions weren't a thing). Trombe walls, solar hot water (usually using salvaged radiators), solar chimneys, superinsulation, earth sheltering, water powered generators and plenty more. Most of the people only had a rough clue about what they were doing and how well it would work, not much idea about what to prioritise, nor whether any of it made economic sense. And intuition was the only way of knowing whether or not a brilliant idea from Arizona, Tokyo or Stockholm might have any relevance in Abergavenny, Brighton or Clydebank. The revolution that PHPP brought to this jungle shouldn't be underestimated. It's difficult, for example, to be a member of this forum without knowing about the key ideas it helped popularise - such as airtightness, MVHR, superinsulation and triple glazing - even if there is a case for prioritising ASHP, PV & battery storage (at least in Ireland).

An interesting article, these are the key elements for me: ...I don't think Banks pays nearly enough attention to airtightness, ventilation, humidity control and health. And he doesn't even mention what should really be Step 1: an audit and a plan to determine the best balance of "enough fabric to improve comfort and health" and heat pump sizing. With Passive House Plus being Irish (not sure about Nigel Banks), maybe the fact that most homes in Ireland are heated by electricity, rather than gas, makes choosing a heat pump a no-brainer anyway. FWIW, without first getting an approved audit, it's not possible to get a grant for a deep renovation in France.

This type of waste is fairly common in France. During my previously mentioned hotel experience when flexible tap connectors were bursting all over the place, there were zero problems with flexible waste pipes blocking or leaking, so I wouldn't be concerned.

Yes, hemp is a good insulation. It's not going to slump and it will usefully increase the decrement delay (keeping the house cooler for longer on hot days), in addition to its eco benefits. Be aware though that you need a saw with a wavy-edge blade to cut it - an electrical one is vastly quicker than a hand saw, so strongly recommended when house-size quantities are involved. Maybe the factory can lend you one as part of a potential deal?

It will certainly be interesting to know how well it works - white fabric should help to reflect a bit more, if it's available. Another thing you could try, if it's not too disruptive, is installing ceiling fans - I should have mine in place for next summer. A paper by Steven V. Szokolay suggests that the air movement they generate makes it feel significantly cooler, depending on the fan diameter. For a room of 20m² or less: 900mm diameter = 1.6°C 1,200mm diameter = 2.4°C 1,400mm diameter = 2.8°C For rooms >20m², the cooling effect is reduced by a factor f, where f = 20/room area. Or install an additional fan to server the next 20m² block.

A good view is a big asset, but so is space - so how many hours per day will you be sitting down to eat in the dining room (during daylight), vs how many hours will be spent in the kitchen? And if you turn the worktop extension I proposed into a breakfast bar, you would see the view through the kitchen window too. Tip: make the bottom of the kitchen window flush with the worktop, and site the cooker & sink to one side, so that there's minimal interruption to the view. Also bearing in mind that anyone in the dining room on the wrong side of the table doesn't get to see the view, and in summer you might be eating outside, rather than inside Of course if 'dining room' actually means 'office', then keeping the view on the dining room side is easily justified!

There could be some confusion about which you meant. 3 to 4mm is common between door and lining (and 4mm is the maximum allowed for a fire door), but 2mm is standard between the door and the stop.

Yes, 2mm is standard - more-or-less the thickness of a 10p coin.

Without reworking the whole design, the main change I'd make is switching the kitchen to the other side of the room, allowing a larger living room by cutting down on the 'virtual corridor' space on the original: I'd probably use a little of that space gained to make the main bedroom suite a little wider.

The latest French news on the topic is that 109 'electrification zone' candidates have just been approved, many in rural areas, some in towns & cities. They get financial, technical & other support until 2030 to implement local projects to phase out fossil fuels and boost electrification in any area(s) of the economy, from housing & transport to trade, industry & agriculture. Decommissioning some of the gas grid is a particular priority - apparently it's already happening in small areas of Bordeaux, Grenoble, Lyon, Metz, Nancy & Strasbourg. Full details are due in the coming months, with projects being launched at the end of the year. More in French: https://www.electrifions-la-france.gouv.fr/territoires-delectrification & https://www.banquedesterritoires.fr/les-territoires-delectrification-enfin-devoiles

Interesting - with Coanda Effect too. And, by the look of it, lugs for a cone filter.

You seem not to have a roof yet? I wouldn't be installing chipboard anyway in that case, so I'd would stick with the birdcage (or I'd be using beam and block at 1st floor level).