JohnMo

Or for a complete answer, if you live in Scotland, where you need a full structural engineering certificate prior to Warrant issue.

Too busy faffing

Or fan coil unit, for heat and cool. Make best of CoP and cooling ability.

With poor insulation under the UFH pipes you will spend as much heating any void below or ground below, as you do heating room. Plus with an insulating screed your flow temps will need to be high also and on for a long time to have any effect on the room, so it's a loose, loose situation. Your ASHP flow temps will be set to manage the floor heat loss of your garage, so CoP will be way worse than its needs to be. Electric heater on 20 to 30 mins on to heat room, then click on off using next to no electricity.

I have just been changing batteries, so of interest. Are they rechargeable?

Electric panel heater on a timer and thermostat. May be just as cheap to run, needs less floor insulation.

And you wonder why things take an age

Manually switch on off lights? Bit boring but it does work well, light go on and stay on as long as you like.

So you have improved airtightness what have you done about ventilation?

Really wouldn't bother with the loop in the utility room, just spread the pipes across the floor, for all the other loops that transit through that room. I would leave everything in the utility. Am I reading that right, you only have 20mm floor insulation? If you don't have lots of floor installation your are just throwing money down the toilet now, and every year in the future.

Making a bit more sense now. Just probably need to do a bit of fine tuning on the flow temps for CH to use the full cheap rate window and have the heat stored you need at the lowest input temp. Your problem could be you are also trying to heat the cylinder and charge for the floor in only 7 hours. You may need a simple spreadsheet, to work out best time to heat water and best flow temp to charge the floor, for the least money. Have attached my ASHP tech spec, which should be good enough to get you going. It outside temp, flow temp, power output, power input and cop. If your heat pump is bigger than 6 have numbers up to 16kW.

That could well be the issue for the cop during heating, your flow temp is way to high. Are you trying to run the heating in short bursts or for long run times? CoP at 50 (at -2) is about 2.5 at best, at 45 you will at 3. Ideally run at 35, 24/7, then your cop jumps to 3.2.

Don't ask the council if it's ok, you may not get the answer you want. Just crack on with it. If in doubt - don't ask.

In Scotland you need an as-designed EPC and sap report to get a warrant - to allow you to start building. Then an as-built to get a completion certificate. Get an as designed, EPC now, make sure nothing is basically wrong with the design, before it's too late or very expensive to change. Take plenty of photos with a tape measure against things if required to show depth etc.

Without knowing the design, the £1500 to 2000 per m2 is meaningless really. The figure is pretty worthless anyway as everyone includes different things for different people.

First lower your cylinder temp. Do max temp of 47 - 48. That will give you a good increase in CoP. 1. Check to make sure your immersion isn't being asked to come on during water heating. 2. Also make sure the controller isn't asking for heat continually so it on off a lot. 3. When the heat pump is doing cylinder heating is it doing it in one run, or does it stop and start doing it? What are WC flow temps and how are you operating? Radiators or UFH ?

Remember to check the max amps and voltage of each string doesn't exceed what the inverter can allow. Big panels need careful selection of inverters as the amps can be high. data for the 410W JA panels - a series string volts increases and amps remains the same.

Just had a quick look, a 370W panel from City Plumbing is £72 plus vat. So 26 panels is about £2k, do the mounting system cost £14k?

Should be cheaper per kW for the solar panel and kWh for the battery. Basically your paying double what I did for your cheapest quoted. My 2 systems (two inverters, multiple isolation switches etc) fully installed, including paying VAT were on average £670 per kW. A big array should have a good economy of scale, so costs per kW reduced.

Real life black panels (310W), GSE integrated with slates.

Yep

No not saying that - but you have to careful you are being ripped off. I have solar (7kW) already and await a battery (13.6kWh) being installed. So I am all for Solar at the right cost.

Have you lost the plot - at those costs you are talking 30+ years of electric costs, you may as well scrub the idea and just pay for the electric.

In Scotland the general thing is to have a rectangular block, as high as the skirting and as wide as the architrave to transition between the two.

Thought your showers ran all the time, your pipes will never be cold