JohnMo

Got all mine from Outsourced Energy. Go to there web shop. No issues at all.

My sap EPC said 5kWh for 2.9 people for DHW. But two of us are using nearer an average of 7kWh. Looks like you only need a 2kW heat source for heating. Have you thought about UFH with Willis heater and direct electric water heating through E7. 2x 3kW Willis heaters (1 duty one standby) some isolation valves, circa £200 in parts. Low capital spend compared to heat pump. Direct E7 heating with PV diverter contribution.

Depending on size of house you may only need circa 3kW, the only ones I came across were LG and Vaillant

Not sure why you asked the question then about minimising screwing, if you are going to answer yourself. Some glue systems only require screws at the perimeter, where there should be no pipes anyway.

A condensing boiler starts to condense at I think a 56 degC return temp, the more it condenses the more efficient it gets. Cut and paste from heat geek, it shows steady state efficiency, a stop start kills the efficiency. 76 more like 70% would be nearer.

They are only that efficient when running at really low temps, well below the condensing temp and running for a long time. Short running periods and high return temps possibly much lower efficiency.

Water cylinder is why cheaper than a sunamp. £3k v £1k size for size, spend a little more get an A rated cylinder like OSO, the heat loss is low also. 300l, start temp 30 finish temp 56, circa 9 kW. Which takes back to big buffers/ thermal stores.

Why not replace the whole things will slim line led fittings they are about 10mm thick. Possibly a bead of sealant to stop drafts. Example of light fittings, I mean https://www.toolstation.com/led-slim-round-panel-light/p71575?store=LJ&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dm&pcrid=558038224734&pkw=&pmt=&gclid=Cj0KCQjw1tGUBhDXARIsAIJx01kit9HU4Z30HFIGvtfHDQNDi6WQvOSsinvm_jkeYgKNOTkA2ocQ7ZQaAjvaEALw_wcB&gclsrc=aw.ds

Small section with the same cross section should be ok. If you worried about noise, insulate around the changes in cross section shape. If it's the same cross section the velocity will not change. Noise is generally flow induced by velocity. You should look up the pressure drop caused by the transition pieces to ensure they are low pressure drop.

Options 1, 2 and 3 all put an insulator (plywood) above the UFH pipes. Option is a cement board and much less of an insulator, so I would go for that. Could the boards be glued down?

Looks like a hard way to make a stud wall. Are there any benefits over 3x2 studs.

Hope you don't go lots of mph, and get a low mpg, while spending your decimal £.

Another nonsense, waste of tax payers money - more living in the past

You be using hangers according to most design guides I have read. design_a_deck_planning.pdf

But they did not say 0.013kW they said 0.013kWh per day. Two different units.

Bought mine new

Think it's the same, but not much losses in when it gets to around 30 degs during heating season. Any other heating is by solar which will get consumed during heating season. But may get toasty in the summer, we will see.

I bought this from eBay. Which is the same as mentioned above, even comes with insulation. Item number 304182801695. This is it installed but used PIR insulation.

Most tray manufacturers do repair touch up kits, they aren't cheap for what they are. Pretty much the same as car touch up kits.

I think it depends more on how the bearing and compressor are lubricated. The compressor can run dry with bearing away from the refrigerant gas or be lubricated with compressor flooded with oil, the same oil lubricates the bearings. Sounds like the ecodan compressor is a flooded compressor, the lube oil works fine while the compressor gas is in the gaseous phase, but when it turns to the liquid state; on compressor cool down, the lube oil no longer lubricates. So a typical start up would be, heat oil within the compressor, flash off refrigerant to gas phase start compressor. Possibly a 15 to 20 minutes delay in startup. So during the heating season the operation of the heat pump, would be, lowest temperature for central heating possible run 24/7 (weather compensation) except for when doing DHW heating. At least that way your standby losses are confined to none heating periods.

Wow - Is that £400+ to be in standby for a year? Just found this article on the subject from 2013, they should certainly drop the eco from the name. https://heatpumps.co.uk/2013/08/13/stand-by-power-and-air-source-heat-pumps/

PHE Sized for. Primary side 6kW input at 27 degrees supply 22 degrees return. There is an additional return temp drop as flow goes through primary coil on its way to the boiler of about a degree. Secondary side 25 supply and 21 return. So an approach temp of 2 degrees. Using PHE (Hexonic LA34) with a size of 471x81mm plates x40.

Don't stair designs have to be approved by structural engineer?

I using a 160l thermal store as a buffer, standard coil rubbish when using low temperature flows. I have just added a large 40 plate heat exchanger as well as the coil.

Two ways to look at things, pump a fair bit of heat in over a short period as you are. Trouble with your approach is air temp is coldest (at night), flow temp at 45 quite high so CoP not the best. Doing the same thing in the day CoP would be better. I am doing similar but with gas boiler but flow temp is 30 for an hour or so longer. 24/7 running with very low temp or weather compensation. Tend to get best CoP heat pump ticking over, little or no stop starts. Heat pumps tend to be least efficient when starting as a far of energy goes in to heating the system and components back up. Think best way to find what is best for you is trial over a week for each approach record comfort and energy use. But both need to be run at as low temp possible. I am going to be trying both approaches again myself next heating season, looking at low/mid 20s flow temp.