JohnMo

Actual rules say calibrated and certified equipment. But I used the same person that did the air test as he did MVHR commissioning also. But everything else was self designed and installed. Pretty easy once you get your head around it.

I did look harder and dismissed G4 for both supply and extract as that is not the normal offering, for a new unit, it's the supply filter that bumps up the cost. But OP wants to go MVHR route anyway. But here is a proper study completed a while ago, worth a read for anyone interested. Atamate_SDAR+Paper+2019+(1).pdf

Your preferred Brink MVHR, filters from a quick look are £70+, depending on area you live, that could be twice a year expense. So may only take the time it takes to make a cuppa, but it becomes an expensive cuppa. Had a dMEV fan running in a summer house a couple of years, nothing has been done, nothing has been needed, could replace the whole fan nearly twice for the cost of your filters. MVHR isn't the only solution, and not always the correct or only solution.

Absolutely nothing wrong with a dMEV system, what maintenance, there is none? The trickle vents are controlled by a membrane that contracts or expands to variable moisture levels, zero inputs from anything else. The fans are commercial available bathroom fans. Greenwood make a nice one, but many others available. Way less maintenance than MVHR. Zero faculties needed, fit it walk away. That cannot be said or MVHR as you need to change filters etc. Same as any other house, I have owned around 10 houses, no one has ever told me anything about maintenance ever. But as said above dMEV, what maintenance?

Ours is nearly 200m² on a single floor. If you are looking at anything near that cost I won't thinking again. If our target airtightness had not demanded it (Scottish building regs) I would have gone dMEV or MEV. Very little in it, heat loss wise. dMEV demand based system Wet rooms, Greenwood CV2 one in each room including kitchen. Or central MEV with humidity activated terminals and constant pressure fan in MEV unit. Automatically and smartly do boost it needed, run at a very low flow all the time. From eBay look at around £40 each, for Greenwood CV2 fans, almost silent, draw almost no electricity, zero maintenance. No trickle vents in wet rooms. Dry rooms, trickle vents that is humidity activated (can include acoustic damping if you need) around £60 to £120 each. Can be through wall or in window. How it works, day time, bedrooms not used, trickle vents almost fully closed. Downstairs rooms have people so the vents start to open in response to rising humidity, fans draw the air across the room, through corridors and out the house. At night the effect swop, now bedroom trickle vents open and downs close. No-one in house, all trickle vents go to min opening. As with MVHR you have internal doors under cut around 6 to 10mm

My first quote 6 years ago was £10k - bonkers. Ended up DIY and spend around £2k

So not much then! Don't they also build things twice, first time as a proof of concept. Then there are all the other parts of the plant all nice thick concrete.

That's a long design life for industrial equipment. Nuclear design life's for equipment is generally way shorter than the same piece of equipment in general industry and it's maintained multiple more times frequently. Think the issue with nuclear plant design is the reaction containment and it's certification. The balance of plant i.e. Pressure vessels, steam turbines, water pumps, piping etc will be overhauled and recertified many time in 30 years plus, with the pressure containing parts regularly recertified, following inspecting for cracks, material loss and wear etc.

Suppose depends if you call it PV or black glass fence panels. And how you interpret permitted development rules on area for a ground array, is it ground area or panel area. 16m x 35mm isn't much ground area. Do it in bifacial panels, so it looks pretty (black glass) both sides rather than black glass one side and white plastic the other.

That's good to know👍

Well done @RedRhino @SimonD PV vertical panel fence, or ground mount. Vertical great winter performance at the cost of a small hit in summer in ultimate production, opposite true for ground mount. DIY install, apply for export via octopus - no MCS in site, or needed. Only issue is panels have doubled in cost over the last 3 months. But still cheaper than a fence panel.

Not really sure you need to be that complicated.

I would look at coanda supply and extract terminals, they will push air across the ceiling/room, and extract will suck air across the room, so makes placement way easier and duct runs way easier. Brink-Multi-Air-Supply-systeem-Leaflet_4388762584830.pdf You can do something like this also, so you are basically supplying air to central location and only extracting from wet rooms

Once you get descaled I would be taking care of the full water and chemical dosing. I filled mine following VDI2035 spec, but later added inhibitor and biocide. The parts I used were on the whole pretty cheap, have read-through of the below thread.

Is the plan to make it airtight - if not don't bother with MVHR. You could instead install a demand based MEV or dMEV system, which responds to humidity with automatic fan speed regulation and trickle vents that open and close to room humidity. I would be doing that even if I was going airtight! Super simple, limited heat losses, cheap enough to do.

Aren't gabions free draining - isn't that one the points of a gabion? I would ask your designer what the perforated pipe brings to the party?

UK government is the majority stake holder with 45% ownership and £14+ billion stake in it. Government money comes from taxes. The UK government funds its 44.9% stake in Sizewell C through a combination of direct taxpayer-funded capital allocations and sovereign-backed financial instruments. So level playing field Never said and never thought renewables are an only solution - but add battery storage, hydro storage, hydrogen generation from excess spinning reserve all help. Hydrogen going to hydrogen gas powered combined cycle turbine generators for background load and or gap filling.

Yes but offshore wind is pretty reliable, seems to generate power most the time. It's dead still here currently - no wind, but the current energy mix is wind and solar, in NE Scotland

Who do you think pays for nuclear? Then managed for the next 1000 years post decommissioning - the tax payer

If you do battery powered stick with one brand so batteries can be swapped tools. Brands mentioned above are all good. But get a drill for drilling and a proper impact driver for screws and bolts, makes life so much better. Impact driver doing screws is a world of difference from a drill doing screws.

Only one useful post above, that's to get a structural engineer. Changes to original plans, adds complexity, things like this needs structural engineer input and design. Making it up with a bunch helpful strangers, isn't the correct way to do it in all seriousness.

Take life less seriously - really wasn't meant to be helpful - just popped into my head reading the post

Build single storey - none of these headaches!

I would be surprised if the savings were that low. We have 200m² house, MVHR, ASHP etc. We still managed to get through 900kWh+ in April. But our bill was £25 (came through today), so saved around £200 in April alone, with Cosy, PV, battery and export compared to standard rate electric. Similarly in Jan with almost zero solar, the battery allowed almost all electric to be 12p cheaper than standard rate, so we saved £200 that month also. Without working each month out, that is closer to £2200 saving a year not £220. A factor of 10 difference, for the better

I would just add your manifold, leave the pipe tails long and mount manifold on a convenient place. Leave pressurised and you can see the pipe integrity via a pressure gauge pressure test with water glycol or air.