JohnMo

I stored our floor installation in the open weighted down with concrete blocks, spent around 2/3 months like that. Was more worried about it be stolen, but two piece were blown into the trees one windy night and wrecked. Cement get it in plastic bags.

Generally the bigger the unit, the less it has to do, so is used at the low end of its performance curve, so for a given duty will be more quite. Pre heating - we are in NE Scotland and not needed it so far this winter, I wouldn't bother. Only really needed below around -5 (ish) Post heating, unless your heating demand is below 10w/m2, there is not enough heat carried by the air to be effective. Enthalpy, again would not bother, not really any benefit in our (UK) environment. We don't get the long periods of sub zero temperature, which leads to air drying. Which is where enthalpy comes into effect. The other thing to consider is Coanda effect supply nozzles. These can be used to throw air across a room and simplify pipe routes. I used two units one small doing two bedrooms and two en suites and a large unit to do the rest. Simplified the routing considerably.

There's two ways to look at this. You take the combi and use as a combi, just make sure its not massively oversized for your needs, over wise it will short cycle on heating duty. The way is make sure it's not undersized and the DHW is then rubbish. But as you are used to using a cylinder and already have space, upgrade to unvented cylinder.

It's a strange world we live in, we are told there is a need to save the planet, but before you can help, fill in all this paperwork and we'll let you know...and once we have had our say, now go through another organisation for them to have their say...

Believe you can only the vat off if being installed as a package. You will need G99(?) approved inverter this will self limit export in an approved manner. I think it is connected to the incomer on the main house meter. The signal will talk to the inverter to control if export occurs or not based in the setting you select on export limitations. Everything else gets complicated as DNO approval is required and will want to charge to loads to study if they will say yes or no.

You could always connect it off grid, to immersion heaters for example.

Give these an email or call. They supplied mine cut to specific size, quick turnaround. http://www.enviroform-insulation.com/

There is a heat loss spreadsheet on here, think it's in the boffin corner. Unless the ground floor is insulated I would not fit UFH, as so much heat will go downwards to heat the earth below the building, your heating bills will huge. You will have oversized rads so you would run them the same as UFH at low temp for long periods. Our last property was circa 1830, the downstairs walls were battened out and rock wool insulation used then plasterboard. But you will remove around 100 to 115mm from each wall floor space. The other two floors had no additional insulation in the walls, the heating bills weren't that bad really. Look to minimise drafts and air leakage. When you install the log burner have the chimney sealed around the flue pipe, I think they vermiculite fill it afterwards. If you make a good job of draft proofing you may may need to consider ventilation afterwards, dMEV fans install in the same holes as normal intermittent fans, but provide slow and quiet controlled ventilation continuously.

My suggestion would be - Go to B&Q (or other similar outlet) and pick up loft legs. Less thermal bridging than metal, less time, sometimes life is just too short.

I have tigo optimiser and Growatt inverter. But mines 10 panels in a row as a single string. All seems to work ok. With panels on different elevations you would ideally do two strings. But I think I would just go down the route of micro inverter, no optimisers required keeps it all simple.

Or is that 1/10 the cost

Why not use 15mm PIR. Aerogel is super expensive. Same insulation value about 1/3 the cost

Would you need to add a zone valve or manual valves also and effectively circulate through a loop that does not involve the boiler. You need your underfloor heating pump to start, but you also need a loop forming that is upstream of the UFH tcv. This will allow the discharge side the the UFH manifold to flow somewhere and give an inlet flow through the tcv and pump. Without this your system will not move water about the circuits.

I'm just using wireless timer thermostat. We like the house temp around 19 degrees. I know if there is any sun out we will get solar gain also in the winter. So I set the thermostat at 19.5 at 01.30 and at 18 at 07.00 this will switch off the heating, if it's not at 18.1 the heating will remain on for a while. Have found the temperature continues to climb slowly until about 09.00 where it is at about 19 for the rest of the day. Our living room is 20 at the moment (sun out), zero degrees last night, and 6 degrees outside now. We are not quite passivhaus.

Difference in price between day and night is 4x. So you could have cost saving with immersion on coldest days for DHW?

Think I went through every possible solution for our roof including multi foil. I ended up spray foam, reflective airtight vapour control and 50mm service void. If I had a clean sheet of paper I would consider just having external insulation, no cold bringing to think about, easy enough to install. All you wood is within the heated environment, so no condensation risk.

I found through experiment that the lowest input (kWh) to the house for heating is batch charging the floor. Basically the UFH goes on at 1.30am and is run until 7am with a flow temp of 30 deg. Tried running the flow temp for the UFH as low as I could, continuously but the kWh input was huge (nearly double) in comparison. For more or less the same temperature in the house. This depends where you live, ours went of, for a couple weeks and now had sub zero nights, little or no solar gain in the day and day time temps not much above 5 degs. So heating is back on.

If you don't want concrete, why use a screed, which is concrete. Use the proportion of concrete you were going to use in the screed and do strip foundation and insulated suspended wooden floor. Or passive slab. Was told not to use screw piles on a building as you make it worthless, screw piles may have a 50 year life, but a normal building should be there for 100s. How do you replace a corroded screw pile?

If you are going fixed price, make sure you include everything you want in the price. Changes after quote will be expensive. Go over what lights, what sockets/switches etc you need, wall finished/ materials. Make sure you know spec of windows and materials, same for internal and outside doors and handles etc. Know what heating system you want. If you are going airtight, get an air test prior to plasterboard and at completion. Make sure there is a requirement to fix air leaks to meet agreed airtightness after first test. Sounds like lots of decisions need to made, but make them once and stick with them. Upgrades and downgrades always cost after an agreement is signed. If you are not sure agree a per M2 cost to added to fixed price, then if you decide on a floor tile more or less expensive you both know where you stand.

But the air in the cavity will not be at 20 deg unless you have a huge depth of insulation on the outside wall. The cavity assuming no other insulation will be midway between inside and outside temp. So 20 deg inside and -2 outside, it would be at 11 degs, a lot less if a ventilated cavity. On a cold winter day do you choose an insulated coat or a thin single skin rain coat. The single skin will trap air, but you will be very cold. The trapped air the installation keeps you warm.

You will need to look at your contract. But you have paid for a service to be completed, the drawings etc were completed at your request using a paid for service, so they should belong to you. Ask him/her for the the drawings in the native formats.

Not sure if you have soak aways - these can be dug out etc. As there is nothing stopping you as the land owner digging holes. You can bring services on to site, water, electric etc. Rebuilding a walk is a maintenance task, not covered by planning regs.

True, based on 0.4 P/A. 100mm is 0.14 150mm is 0.1

If you are going for UFH make sure the floor is well insulated. Aim for a U value of 0.15 or better. Circa 200mm PIR will give around 0.1 or 150mm around 0.15. Screed on top of the insulation and UFH pipes to bring the floors level with existing.

It will rise, but whether you need heating will depend on your insulation values.