SteamyTea

Two different ways of measurement there. Comparing delivered energy with primary energy is a bit naughty. To David and Helan Why would you not try and get an airtight building while it is a shell? Beat the architect with a stick until he works out a decent method of detailing that can be constructed.

Is that because it is aluminium extrusion? Taking a leaf out if SpaceX book, stainless steel would be stronger and lighter than aluminium, or CRF for that matter, and I think it conducts less heat.

Ask a builder, then reduce by 20%, but buy them a tape measure and sharp knife.

Good if you want to use a lower flow temperature. 3500 litres of oil is not excessive, about 35,000 kWh. At nearly 400m², you are using about 90 kWh/m².year. Pretty average. I use 42 kWh/m².year in a terraced place, in Cornwall (just the heating that is). You could put in a simple electrical resistance heater in a buffet tank, or a Willis heater plumbed in directly to the pipework. Then dump excess PV into it. Buffer would my option as you can retain the current oil burner. So work in airtightness and insulation, worry about the technology once you get your oil usage down to 18 MWh.

VR headsets.

Yes. I like joules as a unit. It is more relatable to mechanical things.

Happy to take that away as well. Magpie me.

Buy a 4 port one and you can plumb in any combination.

It should be possible to, in effect, make a freestanding sliding door. This would be mechanically fixed to, but not structurally part of, the wall. Then clad/cover to make the pockets. @craig may know how to do something like this. There are some cars original Merc S class, that had electric windows, that were double glazed, that slid into pockets in the doors. They could survive and work reliably, at 155 MPH, and bouncing down a rutted road.

GRP, the better third option.

The worse job I every had to do was cleaning out the DE filter at the Sheffield YMCA. I have no idea what those young men got up to in it. It was worse than removing the Queen's Club, in Bayswater, steamroom in the early 90's

You (ex) Bristol Boys and your night time activities, this is a respectable website.

Engineering wise it is going to be large. A large steel beam, a thick wall and something like a railway track to step over. It won't look like the picture, more like a Peugeot 309 sunroof.

Monitor your energy and temperatures. It tells you a lot about what is going on.

Whoops, yes. Even at the beginning of a sentence. Yet another reason we should be using joules for energy, as that is allowed to be 'Joule' in that circumstance.

Some concretes can set in water. https://www.concrete.org.uk/fingertips-nuggets.asp?cmd=display&id=1031

A proper meter?

Not the length, its is the girth that is important.

Have you thought of buying a cheap one to see how it works? https://www.appliancesdirect.co.uk/p/tf-12000ch/telefunken-tf12000ch-air-conditioner-air-conditioner If it is successful, I will take if off your hands when you are done for free (saves getting an F-Gasser in).

https://www.engineeringtoolbox.com/wood-beams-strength-d_1480.html Measure the size to get the volume, multiply by the density, then multiply by gravity. That gives you the force in Newtons. Then measure the width ad length of the lintel, in meters, to work out the surface area. Then divide the N by the m2 to get the N.m-2, AKA pascals.

Cussedness sounds better in Scotch.

Used to make tooling to mould PU. The factory used to squirt it every where. If you think a tin of squirty foam is uncontrolled, watch an idiot with a proper industrial injection matching with shot weights of 7 or 8 kg. Fantastic mess.

I have always fancied an outdoor fish pond, with colourful tropical fish in it. Goes back to my time as a kid living in West Indian islands where we used to get guppies out of ditches and cross bread them to make them colourful. So why not dump the power into a small pond. Kind of thing @ProDave would do just to stop the DNO having any. He you use it to rear trout in the winter, then boil them up for supper in the summer.

I don't think doing this job well will be that hard. Get yourself a half decent cordless drill from Screwfix, or Lidl even. You will need one anyway. If you are adamant that you cannot get under the base frame at all, then you will have to 'work from the top'. You can make templates from cardboard for any rodent proof mesh (you will need to buy some tin snips) and then place them in each void, attaching to the frame with a decent adhesive (CT1 maybe). Them fill with just about any insulation type to the top of the frame. Then a 12mm flooring board, then 50 to 70mm rigid PIR or PU insulation sheet board, then 18mm flooring sheet. This may seem over the top, but heat loss through the floor gan be quite large. You will also need to fill up the perimeter gap between the frame and the ground to stop air movement. Though I suspect you will need a bit of ventilation as the ground will be damp for many years. Or just pour in 2 part expanding foam. https://www.cfsnet.co.uk/acatalog/CFS_Catalogue__2_Part_Polyurethane_Foam_Liquid_415.html

Wasn't it our @Ed Davies that played about with a modified 3 phase element to get a range of different powers. Not sure if it was an academic exercise or he did it for real. Give him a shout. https://edavies.me.uk/