JohnMo

You have a mix of concrete and aircrete blocks. What did your drawings state should be used?

ICF build here, no issues, all information given to the insurance company. Came back as concrete walls, which it is. Most build methods are standard really. Timber framed - that's how nearly all homes in Scotland are build, brick and block, is how most English homes are built. ICF is just formwork with concrete cast inside and the formwork isn't removed. SIPs are really just timber build, wood with insulation already in place. We are using One Call for home insurance.

I must have been lucky at £525 for my gas connection. Even though I now have an ASHP I have kept the gas, as I don't have my UVC installed yet. But looking at costs purely DHW from gas. And basically endless hot water, from a preheated combi boiler. Gas standing charge is £0.275 / day, so £100 per year. We are currently using circa 6kWh of gas per day, at £0.0685 / kWh. So £150, so all in £250. ASHP on DHW should average out a CoP of between 3 to 2.5, plus some minor cylinder losses. Cost for ASHP (6 multiplied 365), divided by 3 (CoP), and then multiplied by £0.273, is £200. If CoP is closer to 2.5 the price is around £240. All in all not much difference in cost just from a DHW perspective. Environmental perspective is different, that's why I have a HP UVC ready to install. That's a big unit for a new build?

The grids you had on the first post are not foot friendly, would need your shoes on to walk over. Look at ultradecking.co.uk also

That's only if it cost you £5k.

If you have a controller that supports load compensation, and it is, say located in the living room (where I assume you have radiators and not UFH) if the sun is warming up the room the load compensation controller will modulate flow temperature downwards to reduce radiator output. But on S plan that would most likely not work as you will have fixed output temperature.

Depends on how the boiler is installed. If on S or Y plan, the boiler is fixed at a set output temp for heating the cylinder and and CH. So is pretty much on or off from what I can tell. If you need to spend £800 on controls on top of the boiler cost, I would be looking at a boiler that will control all the correct things out the box - examples are Alpha, Atag, Intergas. For good efficiency you need a boiler setup to do weather compensation, you can then set a curve that gives lower output temperature based on outside temperature. If you have radiators where the controller sits, load compensation is also good. None of this will fix your short cycling on UFH when that is run in isolation, without some form of buffer or volumiser.

Should read kW not kWh I said that at the start of the thread, and basically got ignored.

Stairway open to kitchen requires a fire suppression system, but the 3 storey building may require the same anyway. You may also need self closing fire doors and seconded escape. You need to read that sector building regs so you don't get any nasty expensive surprises. There are few topics on here about it.

Me also, left school did a 4 year apprenticeship, spent 12 years in RAF fixing jets, did a degree, spent life as a Mechanical Engineer, designing things way more complex than a domestic heating system, but don't qualify to enroll on heat pump design course to allow me to do MCS install. We do live in a strange world.

My real comment is why bother, just move. Stairs looks to be directly connected to a kitchen space. Big no no. Number of bedrooms doesn't match the downstairs space. Just looks big for the sake of being big.

But just a throw away statement, that just about meaningless. Without being matched to the heat loss calculation, that could be true for a new build or old build, equally it could be false for both.

Simple answer no. For example UFH and UVC. As the two have different flow paths via a 3 way diverter valve But if you heated a thermal store, it would provide DHW and heating via the same cylinder - then the answer is yes

Call them direct, they will have a spares dept.

So how it works Water comes in to the system as noted in @ProDave drawing, via a temperature regulating valve. It comes in via a regulating valve which is sensing the water temperature of the upper manifold - the hot water (from boiler is mixed the return water in the manifold. The pump pushes water from the lower to upper manifold, around the loops and back to the boiler. On the upper manifold water is restricted from going back to boiler by the lockshield valve. The lockshield valve balances what goes back to the boiler and what gets pushed through the UFH loops. Your manifold is installed as it should be.

Passivhaus heating requirements are based around a ventilation system doing 0.3ACH and the amount of heat that air flow can delivery. That being 10W/m2 max, any more the dust in the air starts to smell burnt. You really need to do a whole house heat loss calc, to see where you are heating wise. You could always back fill any heating short fall with electric panel heaters, for a couple of days a year. You are bit vague on what your system is but is it a ventilation heat pump type of thing?

That's what I have available, my peak at -9 was around 16W/m2, but average over the heating season closer to 8W/m2 for the last heating season.

We have a wall longer than 12m, ICF build and the structural engineer required additional structural steel in the wall half way along. Would think your wind loading would have an effect on any needs also. Would think this is all stuff your structural engineer would sort out.

Slight problem, the above assumes you 1kW of heat available for each m2 of concrete. My floor works on 0.03kW per m2, i.e. 192m2 and max of 6kW from ASHP. So heat up times are a slower, but once up to temp the heat is just dripped in.

Yes runs loose in the outer duct. There is an air space, between the outer of the insulation and inner of the outer duct. I actually wrapped the insulation in aluminium tape also. The armour flex is close cell foam so shouldn't absorb water, the outer casing is mechanical protection and stops the insulation being compressed by the weight of the soil, sand etc.

Generally I would say no, You end up with a few head aches, due to the position of the combination valve and the relief valves. Generally the expansion vessel will be directly attached to the combination valve and piping to the expansion vessel will rise from the Combination valve set. The other thing that affects the position of the combination valve, is the relief piping and the limitations on piping length before and after tundish. You have a max of 600mm before the tundish and you are required to a minimum 300mm straight length below it before any bends A typical install instruction says "Expansion Vessels Installation To prevent water stagnation and particulate accumulation affecting water quality, it is recommended that the expansion vessel be installed in the vertical orientation so that the fitting accommodating thermal expansion or a pressure surge is:- 1. bottom fed and upright; and 2. that the connecting pipework to the fitting:- - rises continuously; and - is kept to a minimum;

With the cellcore, the architect is expecting some ground movement below the slab. Could be the B705 is a typo. Can you not miss out the architect and go direct to the SE?

Your not asking them to recommend, a thick concrete, imagine a big storage heater, you can almost dump heat into at any time. It is a slow heat store. If your house is well insulated the floor temp will rarely be 1 or 2 degrees hotter than the room target temp, so becomes self regulating. If room temp exceeds floor surface temp the floor stops giving heat out. Down side of thick floor, you almost operate at 12 hour delay, but if know that you can play with it. You can batch charge the floor at cheap rates or use excess solar to store away heat etc. Thick floors take a bit of getting used to but don't see any real issues.

A quick Google search shows their operation range, is down to -20 degC. So do you need to do anything? Insulated batteries isn't really a good thing, they generate heat while charging and discharging.

I think most are made by a local steel fab shops, as custom design; rather than an off the shelf item