ProDave

The occupant of the room behind will NOT thank you for doing that, with the noise of the thing flushing and refilling every time. Outside wall is a FAR better place for it.

Have a look here https://www.flue-pipes.com/ That is about the cheapest I could find and where I bought all mine from. They have several guides how to do it. Where it goes through the roof, you usually have to cut a hole 50mm larger than the flue (so all combustible materials remain 50mm from the flue) and then cover inside with a stainless steel plate and outside with a flashing kit. Others will have to advise what flashing you need for your shed roof. Yes the flue pipes are expensive. I spent more on flue pipe than I did on the stove.

Even if you were going to control a heat pump via the relay from an eddie I would not do it by turning the power on and off, instead it would be via a thermostat or call for heat input. I just have the timer set so DHW heating only starts at 11AM on the hope the sun will be out by then. A lot simpler.

None at all. The HW cylinder is in the spare bedroom that is the smallest of the three and north facing so gets very little solar gain. There are no issues with the room being too hot, even in summer and arguably the small heat loss is beneficial to an otherwise unheated bedroom in the winter. I am convinced in many installs I see, the vast majority of heat loss is from uninsulated pipes connecting to the cylinder. It was surprising just how far from the cylinder you have to insulate them properly to keep heat loss down.

Hi and welcome. I tried to buy a plot of land 35 years ago to self build my first home and hit a brick wall that it was financially impossible. Instead I bought a developer box as my first home. The issue then was nobody would lend to buy the land, but they would lend to build the house if you could buy the land. I think things have got better since then. The rough location you are looking might help.

Most flue manufacturers will make a special fitting to go on the bottom of the twin wall to convert to single. This is what I did in the caravan. I then had to add two 45 degree bends to make an offset as taking the flue straight up from the stove would have been right in the middle of a roof rafter. You could take the twin / single adaptor straight into the stove, or a short length of single wall flue.

Very similar to the issue I am still trying to resolve. TIP for rendering. ASK HERE FIRST if your chosen system is any good. Certainly don't use the Baumit rubbish that I used.

The upper part, the render, looks okay, terminated with a bell cast bead. It's the lower part that is just wrong, I have never seen it done like that. If it's done properly, the upper render will terminate at the same level as the damp proof course. the lower part is then usually rendered with smooth render. No beads needed, it goes right up to the underside of the bell cast and is a thinner coat so it does not stuck out as far. So I would be wanting that whole bottom section removed and re done properly without that silly gap. You can see from rainwater downpipe, that this bottom render sticks out further than the bellcast of the main render which is totally wrong.

A 300l tank heated to 48 degrees is not enough for 24 hours if 3 people all have a shower plus other uses so it may need topping up later in the day

We are both semi retired so usually one of us is about for part of the day. If we are going to be out, we will set the dishwasher or washing machine on a timer to come on about mid day. something like 1/3 of what the panels generates goes to the immersion heater.

Put 20% cold water in the cup then add boiling.

What happens when you try to upload them? there is a size limit on attached files, if that is the issue can you reduce the size?

No pictures? are you having trouble uploading them? we need the pictures are your terms like "plinth" are not usual terms so we are guessing at the moment what the issue is. But how old is the property? and where?

So the flush plate is about basin height? That seems about normal. A better picture might tell more. but if you have a loo in a vanity unit there is no way it would be any higher than basin height so just how high would you like it?

I find I can self use almost all of what a 4kWp solar PV generates just by self use and the immersion heater diverter, which makes the case for batteries harder to justify. It really only seems to be a benefit if you have a larger PV array so harder to self use it all.

Get your DNO out to identify the cable position for you, they did this for a neighbour building a porch extension. They found the cable was right where they wanted the extension so the neighbour had to pay to have the cable re routed, which involved a pot joint and extending it. They would not allow build over.

Mine is on the first floor, so some go up into the loft for the upstairs rooms, and some go down into the floor void for the downstairs rooms. Every install is individual, there is no right or wrong.

The easiest for DIY is the semi rigid ducting and a radial system to a plenum box.

It is never as simple as you think. Solar PV is a good companion to an ASHP but it is wrong to think of it in terms of "solar PV will heat my DHW" The reality is "Solar PV will reduce my electricity bill" The trouble is solar PV is maximum in the summer and of course only in the daytime, with max output at mid day. so you have to think how can I shift as much electricity usage to close to mid day as possible? Three things work for me. No 1, I have the ASHP timed to start heating DHW at 11AM, there is a reasonable chance of decent solar PV generation by then. No 2 use the big appliances one at a time around mid day. and No 3 install a solar PV diverter, so if nothing else is using the PV generated power, it will go to the immersion heater.

Many think the BC ventilation requirements are too big, and after sign off turn the unit down to a lower ventilation rate. Passive house does not require such a high ventilation rate.

I think the missing detail is WHAT is in the garage? supply head? Meter? Consumer unit? What is going in place of the garage? Where do you want the supply head, meter and consumer unit to end up? Picture of what is presently in the garage?

Once you get down to good air tightness and good insulation, you will find that more heat is lost through ventilation, than through heat loss through walls etc. That is where mvhr is worth it for cost savings. But even before that point I think mvhr is worth is for the better comfort in the house. I used to hate wind howling through bathroom fans and the cooker hood when it blows a gale. You get none of that with mvhr, just constant controlled ventilation ensuring fresh air and no damp, without losing a lot of heat from the building. Most of us here have tried hard to build our houses to way better than building regs standard, the target for most has been something close to passive house standard, and many achieve that with certified passive houses. Others like me were not bothered getting it certified as a passive house but still wanted to aim to be close to that using all the same principles. It all depends what you want. With the direction fuel costs are heading, it just makes sense to make the house as low energy as possible.

@Adsibob what is your actual issue here? Just that the ceiling corner is square but the stairs are rounded as they turn the bend so it overlaps a little? I take it the "skylight" is walk on glazing?

Trusting an external render to actually be waterproof and stay stuck to the wall. So now I have told you mine, you tell us yours.

That 180 heating days will not be equal. Likely 50kWh per day on the coldest days, and considerably less at either end of the heating season. No idea what the capacity of the Tesla is, but I doubt it is anywhere near 50kWh