JohnMo

On the boiler questions, if it's heating the house now, it will heat with an alternative heating system, as the energy lost from the house will not change. Unless of cause you do UFH without suitable insulation below the pipes, then loads of energy will be pumped into the ground under the house, as that would be the easiest path for the heat to travel.

I would be careful with thermostats everywhere, that the boiler can turn down enough to cope, otherwise the boiler will just short cycle and use loads more gas, or if heat pump lots more electric. Remember the house heat demand is for the coldest day, anything warmer it requires much less energy, every zone or rad that is off is even less energy being consumed, the boiler cannot turn down enough to dissipate the heat generated, so shuts down because the return temp is too high, waits for 5mins starts again and repeats. Going Smart everywhere is the the smart thing to do.

Not normal but could work, if the loft space is outside the heated environment, your heat loss could be large, even when very well insulated. Don't you have a cupboard or wardrobe you put the manifold in?

Design it yourself? Keep flow velocity low, semi flex duct and plenum/manifold. Silencer between MVHR and plenum. Keep MVHR unit central so duct runs are as equal/short as possible. Specify MVHR unit one size up from your target boost flow rate. Extract air out of wet rooms, supply it to dry rooms. Supply and extract flows match overall.

If they are installing and supplying they should not be charging you vat at all on anything.

What ever you do smart, will be old hat in 10 years time and not supported. Keep it simple, and replaceable, but install cat 5/6 data cables to TV points.

Think the bath is an accident waiting to happen, you would stepping in to the sloped part of the bath. Think he may spend his time reading in a bed recovering from a slip/fall, instead of the bath. Just my thoughts

Same here, I bought two units from eBay, no warranty. One unit no issue the other although it worked, it needed a new fan motor. Even after buying the fan and motor, I saved a couple of grand.

Bit of a random question, without any specific details?

a pump should not be noisy, air in system, or lack of pressure upstream will cause cavitation which will make a racket. Also a gas boiler should be near silent.

2x small heat pumps would give you turndown of 6 to 8:1. Or if you have UFH, batch charge the floor, basically put X kW into floor over a period of hours and it will slowly heat the house for the rest of the day. Or thermal store. Use an oversized PHE for DHW generation with a 2 degree approach temp. So you are getting 46 deg DHW from a tank at 48. Up the temps if you need. Take heating supply from thermal store.

MCS certificate manual suggests "inverter ‘turn-down’ available (typically 25%)." So likely you will not find much better, than you have seen already.

Isn't that one of the reasons for buffers, to make up for the short fall in modulation. Why would you need your heating on at 16 degs outside? Also MCS certification manual say to the heat pump is to meet the duty of an outside temp for 99.6% of the year. So the worst 5 days can be ignored for sizing. Which leads to a smaller unit being specified. And helps with modulation range etc.

I just risked it and didn't bother with insurance. Had a wheel barrow and couple of shovels kicked, and the excess wouldn't of covered those anyway. Most stuff of value was either kept off site until needed or within a locked and out of sight loft section.

I would really look at the cost benifit v cost. dMEV fans may be a much better option, worth looking at.

You could also directly charge the thermal store from the heat pump or go via a plate heat exchanger. If you used a plate DHW exchanger, you may get better heat exchange and able to use full contents of TS or part charge it in low use situation. Advantage is no possibility of short cycling during heating as this would be fed direct from from thermal store.

Look at whole window U value, not at the headline you get triple glazing. Have seen triple glazed advertised as 1.4, because the frames are cr*p. Insist on getting the whole window U value, they will want to give you the Ug valve which is only the glazed part of it. We have some double glazed doors and the whole U value, frames and glazing is 1.1, but they are Krypton filled. Our triple glazed are 0.74 and 0.82. A normal ok/good quality double glazed window is 1.4, triple glazed less than 1.0 for the whole window U value.

I have the same roof lights as above, but replaced the upstand shown with, Compacfoam CF200, from Green Building Store.

Got the manual for the non inverter one, it can go up to 55 and has no phone App. But all the limitations are the same. Single temperature, no external call for heat etc. Does seem to have a timer and cooling pre configured.

But obviously you don't move in until complete.

A normal one should go down to 27. The other way to do it is set your flow temp at the boiler and just use the blending valve as a safety device. That works as long as you don't have radiators at a different temperature.

What ever route you go down, with a low energy house, realise things don't work the same with heating as a 'normal' house. You can operate the whole ground floor as a single zone, without lots of thermostats. I have gas boiler capable of weather compensation, but it just doesn't cope with slow house temperature change and slow change in temperature of the 100mm thick slab. I now just batch charge overnight for around 6 hours. If I wanted to do it quicker you would just increase the temperature. If you have underfloor heating in a thick slab, you can charge it up over a period of hours, then switch it off for 16 to 18 hours and your house will stay roughly the same temperature. So if you have an ASHP, you could do the house heating overnight on cheaper electric. The CoP will not be as good (due lower overnight temperature), but you are paying lots less for the electric. So you are paying gas prices and need less than a third of it compared to gas boiler. Or do as some use a Willis heater, for £60 each, always has a CoP of 1, use on cheap rate electric, same cost as gas, use an immersion or heat pump/cylinder combination for DHW.

I have gone through the online question bit. No answer so far, not paying them to get basic info.

Slip rings? Same as cranes and your car steering wheel.

I asked the same question through eBay about a 3kW unit. They said eBay didn't allow them to send the info. My question to them "Hi do you have a data sheet for 3 and 5kW heat ops please. " Their reply "We do have the heat pump user manual which has all the information but ebay won't let us send it to you, they say it's against their rules and policies.. Thank you.":