JohnMo

You may as well use the immersion

You can change that setting, think there are three settings you can use

Black out curtains. Doesn't mean you have to close them. Or even buy them, so long as they see mitigation. They need a box to tick. Not sure anyone actually checks these planning conditions are implemented, once the planning stage is complete. Prison bars isn't a good look or a great selling point, if you try to sell.

Must say look quite close, but I did correct all assumptions made and all standard details and it dropped considerably at revision 2. But take from this is a ballpark of closer to 3kW, not 8kW and nowhere near 12kW. Looking at the spreadsheet the fabric loss isn't too bad, the ventilation losses are stupid high for MVHR.

Someone dropped a ball there. I would 1 Add a small supplement electrical panel heater. Get one with a thermostat so it only heats when needed, £100 and will take longer to collect than install 2 Reduce WC to suit all other rooms, so all rooms run below the thermostat set point (up setting on thermostat to just above target room temp). This will leave the heat pump to run itself. Comment: Would suspect with most the house bouncing off thermostats the heat pump short cycles or has a buffer, either will affect efficiency The uplift in efficiency will probably pay for the electric panel heater. Dropping flow temp from 45 to 35 will save 0.5kW of input electric on its own. Less ASHP cycling will save also, how much? Using a flow temp of 35 would reduce the output of the UFH by 50% (ish) leaving a short fall of about 8-900W, so a 1 to 2kW heater, depending if they switch off during night and it has to recover the heat in the morning

To need 210mm pipes your house must be huge? Use a directional terminal on the wall, these have the inlet and outlet pipes next to each other. Zero separation required. Use coanda supply nozzles, these can be situated anywhere in a room near the ceiling and air follows the ceiling for quite a few meters before coming down. So assuming you have the unit in the landing cupboard and ensuite ceiling is flat. Bed 3 duct would go over ensuite and out of the wall, bed 2 could have the supply nozzle above the door.

I deliberately went completely the opposite way, our original drawings had flat ceiling had the architect change to vaulted. Every room feels roomy and airy, would not go your direction. What is the motivation? Seems a lot of work to possibly store stuff, you will not use or see until you move house.

Spelling issue

My heat pump explicitly does not defrost during DHW production - it can't be the only one. My worry would be another condition of the heat pump, is if it doesn't hit DHW target before it gets 60, it cuts back DHW target 10 degs, each time. Plus - It looks like they have only tested on a Vaillant ASHP.

Also go on renewable heating hub, tat where the book comes from

That sounds about right our lounge is near to 1/3 our total heat loss. Do they run on a timer, on/off thermostat or on all the time? Do they have thick carpet? Have increased the flow rate in those loops to give more energy out. Run those loop 50% higher, so you get a lower dT (differential temperature). Then move the curve back down to lower flow temp. I have never been above 35 and we have UFH at 300mm centres. What does that mean? Heat loss isn't affected by height, just the external areas. Halls aren't normally designed for 21, and normally rob or borrow heat from every room attached to it.

Just had a look at my SAP report, "as built" and looked at the "target emission rate", which is bog standard building regs, no MVHR, double glazed, min insulation, air tightness of 7. The target build adds around 35% to the as built house. That had a heat loss rate of about 4kW. We are 195m² single storey long thin building and lots of glass. Worst design for heat efficiency. So your 12kW is about 4x oversized for well insulated 3g glass MVHR etc - walk away from that quote.

I agree with everything above. We have a sort of plant room, but also stuff elsewhere. I never heard of plant rooms before this build, and really convinced they make much sense Ours Consumer unit, cat5 distribution and battery diverter box in hall cupboard by front door UFH and hot and cold water manifolds in utility cupboard. 2x MVHR units, one in another hall cupboard Second MVHR, old gas boiler and UVC, one PV inverter and battery in roof loft space (inside insulation envelope) MVHR expansion vessel and a few other bits in an insulated shed, that houses the borehole pump filters and second PV invertery.

Your structural requirement comes first then bigger if required for services. So get them designed, not a random guess.

You can pick up an UVC for £1k incl VAT. Doubt they would need 12k ASHP, something very wrong if they need that. I would if buying again just go Panasonic monobloc R32, they seem easy to tune and run well out the box just about silent - they are around £2.5 to £3k. May cost a little more than £5k, but you will have a heat pump of the correct size instead of some monster. UFH on 200mm centres, on ground floor and upstairs wet rooms (100mm centres). Provide provision for fan coils later if you want them for cooling, run at same temp as UFH. You need two zones at least, so use electrical towel rads in bathrooms to do this. Heat pump system simple wins the day, less cost to install, more efficient - no buffers or volumisers, no manifold pumps or mixers, no actuators or zone valves, just a diverter. If you end up at around 6kW and the pipe runs are short you only need 22mm or if you really want 28mm piping.

Electric towel rads, I would fit those anyway. Do as many on here have done Do your calcs first Buy and install the heat pump yourself. Forget to mention in first post Our living room is 6m tall, has one wall is all glass, all other room circa 3 to 3.5m all with 5m² of glass except wet rooms.

Hi welcome Number of people make no real difference to heat loss calcs. Do you own heat loss calculations. All those numbers sound plain stupid. Our house from your description is similar to ours and our heat loss is 3kW. So sometimes well off. Are you a new build? What does you SAP report state?

Think if your design requires a tight control on internal or external humidity, I think you change design. Summer humidity even with MVHR is all over the place, especially if you are cooling, have the windows open or both. We were hot this morning, cooling on (always on really in summer) 59% at midnight and by 8am at 69%, house basically cooler than outside. House between 20 and 22 outside 22 to 25. Over the last month has been mid 50s and above.

Pretty useless inspection, if he doesn't know the details of what he is there to inspect.

Wood Kraft Moray based in Elgin

I would keep inside and access from the inside. For all the reasons above.

The tables make interest reading. If you have a coldish 10 Deg fill water from the mains, and a decent shower flow, they just don't work well, even at elevated storage temps that a R32 ASHP really wouldn't manage. So unless you really had to I wouldn't bother.

Yep

I found the same so looked at what actually makes up a unit and nothing much. Break down of parts I have used Resin Purolite MB400IND Mixed Bed Indicator DI resin 60/40 1L from Complete Aquatics - I bought 2L for £32 delivered (only used just under 1L so far and its 50% depleted) VYAIR 10" Refillable Transparent filter housing (empty for DI resin - £7.99 from Amazon, this holds the resin and goes inside the 10" filter housing 10" transparent filter housing with 3/4" tappings - £20 from Amazon 3/4 male X2 (for filter housing) and 3/4 female X2 (for fill and flush manifold) garden hose tap connectors - Amazon £14 Some off cuts of garden hose and garden hose end connectors Already had a fill and flush manifold in the system. So about £75 all in (plus the fill and flush point) and have enough resin to treat around 2000L of water. All you do is replace the resin when it all changes from blue to brown. So £16 instead of £160 charged for complete cartridge.

Easy install them and then set to 24 or above, so they stay fully open, as if they are not there. Risk taken away. Various way to achieve the same thing. Why would you call in a Building Inspector?