Iceverge

It's entirely possible to have good air quality without airtightness and mechanical ventilation, you will just use a lot of energy forcing air through the vents using convection. What kind of data do you have on your own house?

Why do people resort entirely to emotions when making decisions about their own housing? I have very bright friends with strong scientific backgrounds who consider airtightness and mechanical ventilation as some kind of voodoo. They refuse to do the sums or accept scientific papers with the same ferver as a creationist flat earther. What is it about our own homes that makes us morons?

Might be less work than you think. 2 plasterers did ours (48m) in about an hour and a half.

Nicely done. I wonder who could have done that. (Mk4 mondeo Titanium btw?

Airtightness.

Exactly this. https://passivehouseplus.ie/magazine/insight/the-small-passive-house-problem-a-solution

Bin the aircrete and the PIR. Dense blocks and mineral wool batts in the cavity will out perform it in reality.

Any drawings of your roof and wall interface? If it's complex then I would recommend moving your airtight layer outboard of the rafters.

Seal any air paths too with acoustic caulk.

No calling me by my real name. This is supposed to be an anonymous forum.

I'm thinking idiot resistant ( not idiot proof, that's impossible). Simple pattern to lay. Single zone. Run at a low flow temp. Would it actually make any difference to the feel of the house avoiding walls beds, kitchen cabinets etc etc.

Ok..... Having a brainwave here .......it's hurting......there's blood coming out my ears.............. Take a well insulated house with an ASHP. Lay UFH at 200mm centres Don't bother with room by room patterns. Just slap it down in a big up and down pattern or whatever. Pour 150mm of concrete over the top and then ensure no one drills more than 75mm into the concrete. And after than go to town with room layout etc. "Trim" heat the bathrooms with direct electric to make warmer if needed. Any reason this wouldn't work?

Yup, I had 26mm mlcp coming from the UVC inexplicably via a manifold to the kitchen tap. It took about a minute and 9-10 litres of water to get warm at the tap. Solved (9-10secs) and about 1l of water to do the same thing with 10mm Hep2O. I should really have put the UVC closer to the kitchen.

According to the makers. MCLP is suitable for hot ring mains where Hep isn't. It has more in common with hydraulics fittings than plumbing. Its rated for 10Bar continuous at 70deg where Hep you'd have to drop to 50deg ish to get the same rating. It's pretty achedemic in a domestic install but for a commercial setting I can see the advantage. In Ireland and UK we can't seem to get the 12mm fittings. I really like the 10mm Hep. Its like installing 3 core cable rather than pipe and for a radial system delivers hot water extremely fast, coupled with the slim inserts I'm getting 6l/min over 16m at 3Bar. That's plenty for everything except a shower/bath or jetwash kitchen tap. Failure mode in my wellwater experience is metal corrosion (copper/brass) and I love that Hep can avoid this almost entirely. I expect the stuff I put in to do 75 years +.

It's been the standard go-to in Ireland with a while for new builds I've seen. You can buy screw fittings if you don't have the compression tool. It's a very robust system. HEP2O is an easier system to install in my experience and has less restrictive fittings for flow and plenty good enough for houses. I would be happy with a multilayer system if done well though. Much more so than copper or cheaper push fit.