ProDave

We still have the FIT of our previous house that is now tenanted. we have to get a quarterly reading from the tenant. When eventually we do sell that house, the remainder of the FIT will get transferred to the buyer.

As above, make it a condition of the contract that the FIT contract is transferred to you. Our old house has a 2kW PV system on the original 2012 FIT rate and it pays just short of £1000 per year, so you should get something similar. That will have been a 25 year contract so another 14 years left to run. Then the 2 things to self use as much as you can to further reduce your bills are shift the use of big appliances like the washing machine to the middle of the day (on a timer if you are out) and a solar PV diverter to send any excess to your immersion heater.

It's now vintage. One of the first digital storage scope's made, it cost me a whole £3 when I bought it not working as "scrap" from a previous employer and then repaired it. I have had it 30 years

You don't want a thermal store with a heat pump. For a TS to have any capacity, it needs to store the water a lot hotter than the delivery temperature, which is completely the opposite of what you want to do with a heat pump.

Don't you want some rain now to set the dry mix?

If that statement is true, it would be the complete opposite of the 1930's semi that we once owned. Solid, unisulated walls, meant it leaked heat like it was going out of fashion, cost a fortune to heat 20 years ago, I would not want to be paying the heating bill for it now. We had fitted better windows and insulated the loft but the basic fabric of the house was poor, and little you could do cheaply to improve it.

The indoor electronics bench

I would be interested to see the makeup of that floor. If it were a low floor void underneath it would probably be thin joists with intermediate sleeper walls, but with such a big space under the floor it might be larger joists spanning the width of the room. That would make it easier to insulate properly to a good standard and with a good working space under. Contrary to what most think on here, I have no problem with a well insulated suspended floor with UFH I did that by choice in both my self builds. With that huge space, I cannot see how you can build it up for a solid floor without the infill putting outward pressure on that very large height you have to build up, and that's one hell of a lot of infill to import to do it.

Except if it enters your heat pump at 0.1 degrees and you reduce it's temperature by 0.2 degrees, it leaves in lumps which the heat exchanger and pipework probably won't like. AND it would have to be flowing all the time, even if the heat pump was not operating otherwise it would freeze in the pipes and heat exchanger. Zoot's stream may not get that cold, but in winter ours is snow melt, so barely above 0.

Ah you need a mechanical workbench in the garage, and a completely separate electronics workbench in your nice indoor workspace (aka the plant room) I don't think i have photographed that one yet so I might later on, if it's not too untidy.

I did briefly think about a water source heat pump from our burn, but to extract that much water (even if it goes straight back slightly chilled) would need an extraction licence and I could not face even attempting the paperwork to get permission. One alternative might be a heat exchanger, aka an underwater radiator? Our burn never freezes, even in winter it is flowing but with ice forming on the banks it can't be much above 0 so not a lot of headroom to extract energy from it or you will be pumping ice cubes back into it.

The BC thing is so variable. Here in the Highlands, BC wanted to inspect and test the foul drainage several times, but did not look once at any aspect of the rainwater drainage.

Just read the regs carefully. In Scotland, the half or quarter landing has to be at least as wide as the stair, so 900 stair and 840mm half landing would fail.

All stairs must rise the same amount, so you can't have one shallow step, make them all the same. I am also pretty sure the half landing must be as wide as the stair, so if you can only fit a 840mm half landing then probably the whole stair will have to be 840mm. Is that allowed where you are ? (In Scotland the minimum is now 900mm)

No 1, while they are in storage, strap them together or lay them on a definitely flat floor weighted down to try and keep them straight in storage. Are you fitting them to block walls (I guess so looking at the picture) My No 1 tip is adjust the door linings to match the width of the actual doors plus a few mm. Doing that, I did not have to trim any doors.

Take a good look. It is rarely that tidy. The rear wall has OSB before the plasterboard went on and just nails to hang the tools on, then drawn round them with a big marker pen.

I have worked on many Grant Vortex boilers and I have NEVER seen that valve used like that. There should be a normal fill loop with a valve each end to fill the system with water until it reaches the correct pressure, then you turn the water off. I SERIOUSLY think you need a different plumber, I think what the existing one is telling you to do is wrong and possibly dangerous.

Solar PV is definitely worth it. Over a year the PV generates more than it takes to heat the house, but of course not when you need it. But we self use almost all we generate and it makes a big reduction in the electricity bill. Many of us find for much of the summer. you get much of your hot water for free from surplus PV.

That's my flue just being installed showing the roof flashing and the rain deflector immediately above it, and the twin wall China Man's hat. (what is wrong with calling it that?) Note this was BEFORE i found the gap between the actual top of the flue and the hat was large enough for a stupid bird to enter so it is now covered with steel mesh.

Flue pipes (in the UK at least) join with the upper section going down inside the lower section. the reasoning is any condensation or tar will run down the inside of the flue. There will be plenty of convection or draught to stop any theoretical combustion gas leak. The cowl, as in the top cap or "China man's hat" on the top is made especially for the particular twin wall flue you have bought. It joins in just the same way as any other twin wall joint ensuring the top of the twin wall is covered so water cannot get down into the insulation. TIP add some wire mesh or at least chicken wire around the gap between the top of the flue and the actual cowl. It is worth the effort getting up onto the roof after TWICE dismantling the top of the stove to retreive the stupid bird that went down the flue. The roof flashing fits differently. It slides over the flue. It does not clamp in the same way as a twin wall joint, it will probably have it's own joint clamp supplied with it. Ours is 2 parts, a lead flashing that gets tiled into the roof, and then a stainless steel cover that clamps to the flue pipe immediately above the lead flashing as a second layer of protection to stop water running down the pipe.

You don't say what size house but our 150 square metre nearly passive house uses 1400kWh heating the house each year and 1000kWh heating the hot water. We are in the Highlands so probably a colder climate than you so expect your figures to be lower.

Yes and only £1897 plus VAT for the 5kW that i have. You end up with it ex VAT on a new build.

With the rear option, watch out for the "distance to combustible materials" particularly for the single wall flue. That could push the whole lot out into the room. I really don't get much heat loss from the single wall section of flue. I think the crucial thing is ducted air into the stove in my case from under the suspended floor, means cold air top and bottom of the flue so little convection. IF the stove was taking warm air in from the room, you could get more convection and heat loss.

Option 2 is what i did. The single wall flue does not seem "cold" when the stove is not in use, certainly not cold enough to cause concern at heat loss. I bought from flue-pipes.com and their black single wall and twin wall all matched in colour and were a pretty good match to the matt black of my stove. For the roof penetration, they sold an insulated sleeve. This is a hard insulating tube that is a snug fit around the twin wall and can be made a snug fit and sealed in a hole in the roof. It was obviously designed to be in direct contact with the twin wall flue so was a neat solution. It is not at all "wobbly" P.S that overhanging kitchen worktop was temporary

I did once had a cylinder where the cylinder was leaking at the point the handle was welded on. I pointed it out to the Calor dealer who seemed completely disinterested.