JohnMo

Welcome and good luck I did an insulated 70mm thick log building for my wife. Works really well. Think of heating and ventilation, so you can integrate before you start.

Most possibly not. GSE already do (and others) simple trays to displace tiles or slates which will incorporate in to most roofs. PV panels are now so cheap they should be the roof material of choice. You just need inverters that can handle a massive oversized array to the DNO happy. GSE also sell an inlet system for MVHR that draws air from behind PV panels, or outside whichever the most beneficial, getting free preheated air in shoulder seasons and some winter days. If you want solar thermal, you can get solar thermal slates, made from real slate, so invisible on a slate roof. Or combine with PV with integrated thermal PV. Rain water harvesting is a good idea, but you need storage space, which is a stumbling block for a lot of properties, without digging up the whole garden to install.

Are you sure, the reason I say that, is our house at zero only need a couple kW, it's 195m2. If I don't heat does it get cold, yes. It's fine at an average temperature of 9-10 without heat. But then it's gets less comfortable. So heat is required. The 2 rooms heated will be cooled by heat transfer to the rest of the house, so by default the whole house will get heated. I would Either A2A heat pump or Install UFH, in thick screed. Use ASHP to batch charge floor and use as a storage heater. Heating time anything from 3 to 4 hours upto 8hrs depends on outside temp and flow temp. Heat DHW via ASHP. 5 to 6kW ASHP (or check the turn down on the one you have) will provide the heat to house on cheap rate electric. Or do similar via a Willis heater at 3 to 4 times the cost. If your heat pump does cooling cool the floor in summer

Possibly a really good name, because that is really the only time you need it after the first year of drying is done.

Titon HRV20. In reality, unless you are crammed with people, building regs flow rates will be way to high you could end up halving them after sign off. So with a large house don't go overboard with sizing the unit. Titon are UK company, good support and spare parts if you need them. Good technical info readily available on their website. You call they pick up the phone, you get to discuss any issues and concerns with technical people.

Depends on 75mm or 90mm and how many bends etc, and flow rate through that duct - assuming semi flex manifold system. All the info should be on the data sheets for duct system, you choose.

If it's only 16m all good.

Not sure a single unit would be the best choice. You need to keep your max duct pressure drop below 100Pa. So you would need to do the pressure drop calculation for your longest duct run to make sure a single unit is practical. A fan output drops as pressure drop increases on suction and discharge sides. The fan output is compensated by increasing fan speed (and noise). So be careful.

I flow at a minimum of 12 degs, but at the bottom of a 100mm screed. Heat for two x 4hr blocks a day will bring the floor surface to about 19 or 20, room temp could be at 26. So pulling a fair amount of heat away. But a bit like UFH heating in well insulated houses temperature are not really very extreme. Think the surface temp in winter gets to about 23, 24 on a very cold day, could be at 19 or 20 without cooling on, when it's wet and dull for a few days. Or 19 to 20 degs when it's hot inside - So we are are only talking a few degrees of temperature swings.

I just wait till the wife is out, and then do stuff. Just make sure you don't have that as the only loops on-line or you may end up short cycling (unless you have a buffer volume). That's because it feels colder than the actual air temperature. The floor is colder than the surroundings and a big area, so it's pulling heat out of you.

That's all we used in each wet room (except ceiling) - but no tanking. Done the same in about 8 houses no issue. Where there are tiles we didn't tape at all.

We don't have a Brink unit, but ours uses volt free contacts for boost. I have just used something similar to this https://www.screwfix.com/p/british-general-900-series-10ax-1-gang-2-way-press-retractive-switch-white/21849?tc=TA5&gad_source=1&gclid=CjwKCAjw-O6zBhASEiwAOHeGxbjClTJurl32V3-e1_kTjztGco0OtS2LAYa7ZsXcrtGteX801eDE1xoCfAUQAvD_BwE&gclsrc=aw.ds Once MVHR is up and running and the house has dried out, you don't really need to boost that much, if at all. Just let the inbuilt humidity sensor do the work. And stick one boost switch in the kitchen as a handy place to have a boost.

Did them in a couple of rentals, never really thought they were that good. Prefer a good old tile. Decent choice of tile, good ventilation (ensures grout looks good for years), equals nice bathroom

I did that and found the floor was looking a matt colour, after 24 hrs, so just do it in 4hr blocks (2x a day) now so the floor surface temp doesn't fall below dew point.

Once your house is dried out you really don't need it too. Not even sure when ours boosted last. Certainly don't need boost in the heating season.

I would be tempted to swop out any intermittent fans for dMEV. You can easily do this one at a time, do high use rooms first, like the main bathroom. These run at very low flow rates, all the time and provide a good amount of background ventilation, cost between £2 and £4 a year to run each. Ideally you would have trickle vents in the bedrooms and living room (not generally needed in wet rooms), then you would get a good cross ventilation effect across the whole house. But with the extractor in the kitchen (when off) the dMEV will draw air in via that hole in the wall and if ventilated to the inside, any chimneys etc. Ideally you would have one dMEV fan in each wet room and kitchen. Greenwood CV2GIP are very quite (almost silent), have automated smart boost so they only boost to the reaction of increasing humidity over a short period (showering for example). They come up on eBay for very reasonable prices quite often. So to answer your question - I would add a fan to the kitchen, but only the dMEV type, most the time it would replace the need to have the noisy main extract fan on, reserve that for smelly foods only.

Not sure you should change any setting, once setup. Not touched mine for over a year except filter clean/replace. MVHR will do nothing much to help cooling, as it only changes the house air once every 2 to 3 hours. We operate the following way. MVHR always on. In summer we keep all doors and windows closed while the house is cooler than outside, once the house is warmer than outside, we open windows and doors to get a good blow through.

So ventilation strategy is where to start. Do you have any mould or damp issues? Have you improved insulation or drafts by doing your changes to the house? Do you have fire places are these all blocked off? Any bathroom fans? All the above helps answer your original question

What is your overall ventilation strategy for the whole house?

Easiest way is to put the thermostat to say 27 degs, that will believe there is a demand for heat start up the UFH. But bigger question is, do you need the complications of loop actuators, pump start delay and the wiring centre. A decent cooling and heating thermostat (Computherm Q20RF for example) and let that start the pump directly. Radiators are useless at cooling.

Speak to your solicitor.

Get E7 electric, direct unvented cylinder heat by immersion on E7. Heat house with a couple of storage heaters

Or the council could order you to take it down i.e. deconstruction

No I am as qualified as any one else, I am the G3 competent person. So can do my own or anyone else's sign off. Our council were not interested in the UVC being registered with themselves.

Yep. I did a course at the local college for Unvented Cylinders and did my own. 1/2 day all done.