JohnMo

I would do Fresh-R, or similar, if I ever did it again. Hardly any ducts to run, on demand ventilation, reduced number of air changes, if the house doesn't need it.

Not the best spreadsheet for calculations. Basically balance supply and extract. Here is some guidance on flow rates. It's a bit of a giggle to get thing matched up. I found it easier to build my own sheet.

Tell that to the numpty politicians all flying in their private jets to COP every year. It all nonsense that could, should, be done via video conferencing from their own countries.

You could do what they show or staple. Use Pert-al-pert pipe as it is easy to form, straightens easily and bends well by hand.

Cold ran down from Manifold, under the floor, then up at the point where the sink was going to be. Photos of stop cock and cold manifold. Plant room is in an upstairs loft section, so main water goes there also. Other photo you can see various white pipes coming up at the outside walls. Hot pipes are in the ceiling and drop down. Walls were all battened to form service gap the plasterboarded

I purchased all my UFH kit from Outsourced energy. Just buy what you need. The floor would be quicker to heat in a thin screed, but only if the insulation is directly below the screed, if it has to heat up the concrete below also it will be no quicker than in the concrete. UFH isn't a radiators system it is slow, suits a heat pump as it can used at very low temperature for a long period. Many on here have directly attached to the mesh. Not really understanding Kore's statement on the mesh being structural as that has nothing to do with the UFH pipes. UFH seems complicated when you first look at it. But is quite simple when you actually get into the nuts and bolts of it. Download a free copy of loopcad. That will develop a plan for you to give to the plumber. Your piping centers can be just about anything you like, I did 300mm, most do 150-200mm. Do loops no more than 100m long. Once you have a plan, you will have piping quantity, number of loops for you manifold etc. Get a low temp mixer/pump such as an Ivar.

I put the cold below the insulation and used a plumbing manifold in a central point. Used Pert-Al- Pert pipes in conduit,so the can be removed as per building regs. Didn't do hot in floor, but would do that within the insulation, as above.

I considered using Prana dMVHR, single unit through wall, automated and looks well made

Why limit to just those manufacturers?

Not wanting to do your project for you, but point you in directions where you can research. You need to build an index of topics you need to cover to justify MVHR, steps to design, choices for the design and implementation, costs 'v' cost savings etc. You will need to know each circuit pressure drop, what noise suppression you need and MVHR unit size you would select, what features the unit will incorporate and if boost will be automated or manual, reasons why any cost and/or user implications. If automated on humidity, what downsides there are in a UK climate and high summer time humidity and how to overcome. If manual what is a user never boosts what impacts on the building fabric. Also look at the UK implications of low internal humidity resulting from MVHR in the winter. Is this an issue in the UK or is it more a cold climate thing. Look at the Passivhaus Institute, building regulations, for the country where your house is sited. There is also plenty of information on this site. You should also demonstrate how your flow rates compare to house volume and overall air changes per hour. Comparing building regs with something like Passivhaus guidelines. Advantage/diadvantages of various system configurations dMVHR, MVHR and hybrids between the two such as Fresh-R. Again look at costs, ease of implementation of new build and retrofit.

But should we concentrate on what is in our control the building we live in and potentially building other people are renovating or building from new. By giving sound, well thought through alternatives, to standard building regs levels of insulation and airtightness etc. Hydro have a number issues never really discussed, like anaerobic decomposition of everything the water has covered, emitting methane for example, which is way worse than CO2.

There are windows, doors, ventilation heat losses also. Interesting your house is 38% the size of mine, yet our heating consumption is 42% of yours. So your heating demand could be 4000 x 38% = 1520kWh per year, so about 80+% better. This also equates to about 1kW heating demand at -5 degC. So would only need heating on the coldest days. So not seeing why you can't make the savings, people convert existing housing stock to passivhaus standards, which is better again. But it takes work. Instead you stand saying look at me, I have installed a heat pump, I saved the planet. Insulation, airtightness and general energy reduction by decreased heat loss is the topic you should be pushing! That is what we need, a real reduction in primary energy usage.

This where I bought most of my parts Seem quite good prices and was good service. They do Iver mixers and manifolds

Would look like you have a big satellite dish in your living room tracking your every move. What would happen if two of you walked in different direction?

So your max heat demand in w/m2 is 1541/144=say 11w/m2 Using the attached you get the flow temp you need, but the chart needs extending downwards, mean flow temps are low/mid 20s. That is to balance heat loss with heat input. If you want to blast heat and use a thermostat just add a couple of extra degrees.

Just go on to eBay and type MVHR, there's loads on there for good prices. I have a similar system and layout to you with two systems. Keep it simple, manual boost switches, you don't need £500 of CO2 sensor. Just a boost switch outside each wetroom and in kitchen.

Not sure you are completely correct. You are assuming the heater has to be electric, but the ones @Dan F references are water filled. Designed to take hot water and cold water also, so can equally apply to a heat pump as much as any other cold or hot water source. Quite a few manufacturer out there doing a similar thing, as mentioned early nothing new. Would agree electric ones not as good as a heat pump heating system.

You could do similar to Mixergy cylinder and not have an internal coil, but use a PHE and pump.

Big coil same as a heat pump, run at lower temperature in the cylinder same as a heat pump?

No the biggest reduction would be better insulated houses. Including your own. Also in your calculations you use the cost of a boiler as £2300, I paid £1000 for mine. Looking at Screwfix the prices vary from £500, upto about £2500, so you have chosen top end to suit your calculations. If you are looking to retrofit a HP the comparison is do nothing and keep gas (then only gas consumption is included), or replace like with like then a similar gas boiler would be chosen. Or replace gas with a HP, life style choice, most in this country cannot afford.

That's because they are, either hot or cold water powered

The hardest parts for me were and are Fitting the insulation into the floor, there seemed like a mountain of it. Then after the house is livable taking another 18 months getting the land scaping, decked areas etc completed - this is still ongoing.

Really depends on the level of insulation you have and how long you have the floor heating running for. Long run times let you have super low flow temps. Our flow temps at the moment are around 26, so floor temp is 21, no perception of a warm floor. As it cooler than your body.

Interesting that it's a water based system

If you have water without antifreeze in the UFH, it could freeze, and if did you wish you had blown it out or filled with an antifreeze. I remember a grand designs where a self builder had water in the UFH, a few freezing days, next thing was water escaping and the floor being dug up.