Mike

If inadequate insulation is indeed the problem, then it's either a specification or installation issue (unless the design required someone else to do something - for example to bury the ducts in the loft insulation).

If there's a long run of poorly insulated duct through a cold attic, then that would certainly be the expected result.

Thanks for the update - good to know that it ended well :)

Before you fit one, first consider whether you have good access from at least 3 sides to be able to clean around it properly, and to give it the space to set it off; a free-stander squashed between other items or against the wall won't look luxurious, it will look squashed.

I think that either of these approaches is good - and why I'm trying to cover both with my 2-tier UFCH controls. It's the stuff that falls in the middle where it gets difficult.

At least you caught it in time :) Maybe because he's recommending ones that only remove half the grease...

Yes, that's right. You also want the MVHR extract terminal a couple of metres or so away from the hood (so the hood does its job), plus a filter on the terminal as backup - either a sock filter (behind the terminal - a good idea on all extracts) or a purpose-designed kitchen terminal (with visible filter).

+1 for @Marko's advice. Also, make sure that the exhaust (to the external air) is either falling towards the MVHR unit, or towards the outside, so any condensation runs out of the duct. If you can find the space, I'd also upgrade your multifoil-lined housing with something thicker.

With grease filtering rated that poorly, I'd choose neither. BTW, recirculating hoods are normally chosen for MVHR, in case you've missed that.

I'd suggest 25mm minimum diameter flexible conduit, with a draw cord + gentle bends, but as straight as possible. Here in France that's commonly used for single cables Cat 6 / 6A cables - I hope so as it's what I've installed. Despite being against the standards, I've heard that it's possible to pull a pair of them through.

They will do better than fibreglass, but won't make a big difference unless you have space for multiples of 100mm. R (thermal resistivity) can tell you how much heat you retain / loose over a period of time, in a steady state. However it takes time for that product to heat up - that is, for the heat to travel from one face of the product to the other - before it stats getting lost at that rate R. The 'travel time' is the decrement delay (déphasage thermique in French) mentioned by others above. In general, the heavier and denser the material, the more the decrement delay will increase. If you're tight on space then adding solid timber boarding or an additional layer of plasterboard will likely make more difference (but still not that much) rather than adding any kind of insulation. Which is why churches, with their thick walls, are slow to react to temperature change. If you want to experiment, the Concrete Centre has a free calculator that you download, from https://www.concretecentre.com/Publications-Software/Publications/Dynamic-Thermal-Properties-Calculator.aspx, if you subscribe to their newsletter.

No, none at all. I used it professionally (as a manager) many times, always specified it when I had the choice, and have always used it on my personal projects, without problems. And although the pipes are a bit more expensive than plastic, you save money on stone fill & spoil removal (you can often backfill with as-dug material). And if you're unlucky and your trenches fill with rain, it definitely won't float, as plastic can. I've only laid the 100mm personally and it's pretty easy. No problem to DIY single-handed if you're practically inclined, hire the recommended pipe cutter & follow the manufacturer's info.

Please do - looks just the sort of thing that I'm aiming for! I enjoy dabbling with the technology, but it's always interesting to see what others have done for inspiration, tips & ideas. one of the reasons for going with the Shelly as the base-level programmer is that it supports MQTT. So far I've installed 10 SHT31-F temperature & humidity sensors above my peculiar unventilated ceiling insulation and will be adding some similar room sensors, plus a bunch of DS18B20s for the UFCH. I'd also like to tap into the Nepronic SHC80 RH sensor that came with my adiabatic cooler, if I can work out how to connect via Modbus / Bacnet.

There's an interesting graduation. If you can get a fine / loose points on your license, then it's complied with - these days French drivers even stop at pedestrian crossings & stop signs! On the other hands, it seems that if you're a farmer then you can get away with most things... ...especially those :)

Almost - 1997-ish - though I'm sure you'll have done more than me! I agree that it can easily be overdone. Having said that, my latest UFCH, currently with very manual on-off controls (plugging / unplugging an extension lead) will be getting 2 layers of controls once the renovation is completed. Basic, using a Shelly Pro 4PM as a simple weekly timer, plus optional 'advanced' controls using a Raspberry Pi which may even do some weather compensation :)

One of my friends just built one where they had to barrow / carry everything through several gardens, thanks to the cooperation of her neighbours. Otherwise it would have had to have gone a longer way around via a footpath and through her house. And my current renovation is on the 6th floor with no lift and no parking. So yes, there are almost always options.

Hepworth SuperSleve (clay) below ground. No strong preference above ground.

Probably not to the letter, but it's a mandatory part of the sales process - which has to signed off by state-appointed notaires. Consequently sales are unlikely to go through without it, if it's evident that one should have been completed.

I've only come across them one, in a place where I stayed. Most of the time the switch in my room didn't work - I had to use the light on my phone to make my way across to the regular switch at the far side. So thumbs down from me.

The same as buying a washing machine with all those menu options, when you normally only use 2.

It may sound strange, but house manuals are (since January 2023) mandatory in France. You're not expected to write all the text (unless you've rolled your own controls), but as a minimum it has to contain (my abbreviated translation): Floor plans and cross-sections A list of all thermal insulation & airtightness materials used in the external envelope, their locations and their properties - material, brand, thickness, thermal resistance Plans, schemas and descriptions for all services - water, electricity, gas, heating, cooling, ventilation A list of the equipment installed that uses energy - brand, model, serial number, power, energy use, energy performance certificate Instructions on the functioning, maintenance & servicing of the above Serving & maintenance records for the above Other documents related to the thermal & environmental performance of the building, such as design documents & certifications, energy audits, energy performance certificates On completion the architect / builder is required to hand it over to the owner (on paper or digitally), who is then responsible for keeping it updated. When the property is sold, it must then be handed over at (or before) contract completion. It then has to be maintained by subsequent owners for the life of the building. For existing buildings, if there isn't already a file then it has to be started when any works are done that significantly affect the thermal performance of the building - insulation, new heating / cooling system, new windows, extensions, etc., including logging what work was done and when. Which means that I have one to prepare.

I'd just choose one or the other. Most likely the green felt as, being heavier, it will resist the wind more, though it would still need battening down.

No, it's not likely to be worth it. Just make sure that it's well ventilated with air bricks at regular intervals on two opposite walls. And preferably make the floor airtight and insulate it - there are plenty of threads on here about doing that

OK as a temporary covering for a few weeks / months, if well nailed down to resist the wind. Chances are that it will disintegrate with UV light over a long period.

They are a cheaper solution than MVHR but they do have some downsides: In winter, it's pumping cold outside air into the house They drive warm moist air to the outside through gaps in the fabric of the building, where it can cause condensation & mould You miss out on the other benefits of MVHR - air filtration, heat recovery, multi-speed control, sound attenuation, summer bypass, etc. There really aren't any circumstances in the UK climate where I'd recommend them these days. dMVHR would be the preferable, if full MVHR has to be ruled out.