JohnMo

DIY'ed all the key points of the design. Didn't really ask for much help from so called experts

We go through icf wall, so pre installed plastic ducts before the concrete pour. You have the two ducts with an 50mm or so gap between them. No issues with SAP, like the Titon units as they are UK manufacturer and the you can actually talk technical to a person on the same wave length. Buying cheap I had a speed signal issue on one of the motors, parts arrived the next day to fix with instructions. Great service. Being Scotland we do a sap at design and completion. I had all the routes of ducts all designed in during design and I actually bought the 2x MVHR units at the design stage, prior to getting the as designed sap. So no issues.

He did, think he mentioned the insulation was so well packed it came out as a plug. Why not just one multi split? Remember if its just for cooling you need planning permission, if it's for heating and can also do cooling you do not.

A ran for a year at minimum speed and never saw any mixing going on by monitoring temperature. Out flow is rejected horizontally outwards, inwards flow comes from below and the sides, so out flow has a hard job making it's way back in.

You can get from 125mm to 200mm so should cover all domestic properties. https://www.paulheatrecovery.co.uk/product-category/mvhr-ducting/terminals-external/ Two MVHR units was just simple. Our house is 25m long and to save too many long duct runs I picked up two Titon units from eBay for peanuts. I also used coanda supply nozzles to reduce and simply duct runs/length and used 90mm duct to make double runs limited.

Have you priced up Frametherm 32?

@Novice what is you normal heat system - ASHP?

When inside is hotter than outside. That is the only time.

Then for the same u value use a decent high density mineral wool batts.

Not required if you use a combined/directional inlet outlet. One of our two MVHR units is in the middle of the house, the two ducts effectively go in void above built-in wardrobes to the outside wall. Our manifolds are in the same void. But it only feeds two bedrooms and extracts from two bathrooms.

So if DHW and it's only getting to 20 degs good chance it is a time related issue. Also check your diverter valve is moving from heating to hot water production. So dig out all the DHW settings

Really makes zero difference, it's the floor surface temperature that's important. Surface temperature is defined by heat loss of the property and how many W/m2 it needs to generate. A well insulated house will have a floor temp only slightly above room temperature, so solar gain effectively switches off floor output as soon a room temp is equal to floor temperature. Once room temp is above floor temp floor will actively remove room heat. Some advantage and disadvantages of thick screeds Good Agonist to heating period, use floor as a buffer for cheap heat. Will retain and give back to the house over many hours. Very gentle heat, you don't notice the heating on or off. Use very low flow temp over many hours, great to reduce running costs. Bad Takes an age to heat up if you allow to cool too much. Different approach to heating than normal. Thin screed, is more like a low temperature radiator system. Still takes a while to heat house but not as long as thick screed. Cannot store heat for later release. Asking for opinion will yield a possible or negative reaction depending on the experience of the person answering. If you want a thin screed vote with your feet and do it

All depends on depth of water, I was near £5k all in.

So let me rephrase imagine walking into an old stone church, it feels way colder in summer than it's actual temperature. Underfloor cooling feels similar. No naked suspension needed. Or certainly never heard of anyone with floor cooling going to that effort, but maybe... well not go into what you maybe get up to.

Suppose the question is what are using the floor for, just parking car or stuff does some run off matter. If your building cars from it needs to be level, then use self leveling compound, dress it once set and paint with floor paint of your choice or just dust seal. Sorry not read the thread just your last question.