Mike

You're right - well spotted!

Not the first time we've had that stupidity. Since it's presumably too late to reposition the post here's one potential solution - search for others. The cold will still travel through the steel, bypassing the insulation so not going to solve the problem.

Very entertaining! Never has I seen such cheer in the face of such financial pain. Great architecture though and yes, the site manager was a star. Looking forward to the follow-up in 5 / 10 / 15 years time...

+1 to a door between entrance & kitchen - in fact I'd probably make a full hallway:

Prior to looking at active cooling solutions, consider passive measures to minimizing the build-up of summer heat within the building. In particular solar shading of windows and the use of wood fibre or hemp insulation to maximize decrement delay, plus the use of appliances with high energy efficiency ratings to minimize their heat output. For active cooling, take a look at using underfloor central heating in cooling mode.

You can - floatovoltaics :)

The main box is an attenuated manifold - item 990323502. Plus you need one end plate with a 150mm connection to suit your 150mm duct (item 990323568, by the look of it), and one end plate with 10 pipe connections (75 or 90mm - 990323614 / 990323615 depending on what you have). So yes, 3 items in total. Check those codes though! Yes, something counter-intuitive happening there - something to do with the extended dimension -v- the wavelength, I suppose. However I note that the figures on the last line - with the 10 x 75/90mm end plate - are different to those in the French brochure. Either the English or the French figures have to be wrong (though whichever is correct still gives good attenuation). I just went looking for the German version, but the one I found doesn't quote any figures at all... Looking again at the French figures, they give them for two connected boxes (160mm end plate + manifold core + manifold core + 10 x 75/90mm end plate) as well as for the single arrangement; the result is more intuitive: 32Hz is really low - I guess it's not normally a concern. I don't think you actually mentioned which MVHR unit you have, BTW?

Here's an alternative for the North East corner that doubles the wardrobe space in Bed 4, and removes the WC from the Bed 3 wall, albeit at the expense of bedroom width in bedrooms 3 & 4. You could probably rework the en-suite & corridor end to avoid cutting space from Bed 3. But everything's a compromise. There's space at the end of the corridor for a shallow storage cupboard.

Having slept in a bedroom with a bath and over-bath shower against the wall (by coincidence in that split-level house), it was a problem for me.

It's true that it can impede mobility on the ground floor but, having lived in a split-level house, it was an interesting & worthwhile feature.

Overall it looks fairly well thought out. A few of minor points: Ditch the sliding doors off the Master Bedroom for something quieter. The wardrobe space in Bedroom 4 is not very generous. Ensure that the partition between Bedroom 4 and the adjacent bathroom sound-proofed Ensure that the partition between Bedroom 3 and the adjacent en-suite is sound-proofed Where will the SVP serving that en-suite run downstairs? For safety, move the hob away from the corner of the kitchen island Do you really need 3 sink bowls in the kitchen (and 2 more in the utility)?

+1. If the Frankische unit is in good working order, then there is nothing to be gained by replacing it. Just build a well insulated enclosure around it - something that should have been done when it was installed and something that your 'specialist' should know. And something that a replacement unit should have too. Several Frankische units have PassivHaus certificates confirming their suitability in cool temperate climates. The larger version of the Komfovent has a similar certificate (and similar-ish performance - compare the Efficiency Ratios), so there's no particular reason to choose one over the other on those grounds. The common reason for choosing an MVHR unit with a rotary heat exchanger (such as the Komfovent) is that they can - if the right materials are used - recover moisture from the outgoing air and transfer it to the incoming air, preventing the air within the building from becoming too dry (which can be an issue in cold climates where the air already has low relative humidity). Komfovent suggest that their units can do that (they "regenerate[s] humidity in winter"), however the PassivHaus certificate for their larger unit makes no mention of this - which suggest that they didn't get that aspect tested & raises a doubt about how effectively it can do it. It also introduces another mechanical moving part which can go wrong. Perhaps, due to their large commercial range of rotary MVHR units, it was just easy for them to scale down their existing rotary technology for their domestic products? BTW, if the Frankische needs replacing for other reasons, then that PassivHaus database is a good place to look for quality alternatives.

Zehnder aren't cheap, but that looks like list price. It should be possible to knock at least 30% off that. The supplier I used (in Germany but delivery to France, not sure if they'll deliver to the UK post-Brexit) are currently offering the main body at a 43% discount (€205 including VAT). You also only need one unit to silence 10 terminals.

Very useful results. So it is the lower end of the frequency range causing the problem. If I were choosing only between the 2 Zehnder options, I'd choose the silenced manifold. BTW, results would normally measured at 1m distance from the source of the noise (ceiling terminal in your case), so the chances are that the 14dB reduction provided by the silenced manifold at 250Hz would be enough, even if your chart suggests that you have 42.5dB of 250Hz noise a few mm away from the Bedroom 2 terminal. You could measure again at 1m to give help decide. No - that is for the manifold only. It helps to know that the manifold is modular - that is you can fit different 'end plates' to it depending on what you want to connect. The results in the table above are measured for the following: a connector plate for 1 x DN160 or 180 or 200 duct on one end (the first part in yellow) a connector plate with 10 x 75 or 90mm semi-rigid duct connectors on the other (the second part in yellow) the CW-S520 is the main body of the manifold (not in yellow). Note that there is a regular manifold body too, without the sound attenuation - the 'S' indicates that it's a silencer version. You would want a connector plate for a 150mm duct (Zehnder 990323568, by the look of it), which isn't one of the ones they used in the test, but the size is so similar to the ones that they did use that performance would undoubtedly be similar / identical.

BTW, to illustrate why it's useful, compare the frequency attenuation of the Zehnder CSI (above) with this one for the Zehnder silenced manifold that I mentioned on the previous page: The silenced manifold beats the dedicated silencer at frequencies of 63, 125, 4000 & 8000 Hz.