Dan F

Depends how you are going to use it, if it's only for sit-down immersive viewing with lowered blinds/lighting then go for as large a projector screen as practical. If you are going to use it primarily for viewing TV while doing other suff without dimmed lights go for TV. If you want both then consider TV with projector screen that comes down in front of it. 65" TV now, pre-wire for a potential 10' projector sceeen is plan here.

Pump will consume next to nothing. The issue with it running it all day is that you get heat-loss (how much depends on how well insulated HRC is): - This costs energy/money. - In the summer this can contirbute to over-heating. On the flip-side, if you don't run the pump enough, then you'll waste water wating for the hot-water to come out of the tap. We've tried to avoid HRC by using 10mm pipe. For the a couple of remote basins that may require HRC, the plan is to use Loxone which will allow me to run a pump based on time of day and/or presence.

Hadn't seen the mat. We're using mostly 14mm on floors including the patio outside. We're using kerlite for bathroom walls, and a couple of bathroom floors, all with standard tile adhesive though. The kerlite stuff is more expensive than the standard tiles. One of the bathrooms is https://www.blustyle.it/ (this is Cotte De Este's second cheaper brand). These (bluetech) were cheaper at £23.

We paid £45 for branded 1200x600x14mm including delivery (from italy). https://www.cottodeste.com/collection/limestone Initial prices i had for these was €30+delivery in italy. £98 from London showroom. Shopped around and found £75, then shopped around more and got £60, then started negotiating (knowing what price in Italy was) and got them down to £45 including delivery. I can’t believe the margins that exist in resale of tiles in U.K.!!

Italian/Spanish or from elsewhere? Thickness? Well known brand?

I did put some in in the end. Not everywhere though, just a few runs from the rack location: - 2 TV locations - 2 Study locations - Loft My initial plan was to buy several 15-20m pre-terminated cables, but I left it until the last minute so instead bought a hundred meters unterminated. If I ever need it then I'll get it terminated. I used OM4 tight-buffered 8-fibre £1.50/m. OM4 isn't justified though and 4-fibre would probably have been enough, so could have paid £0.60/m which is roughly what a good. Conduit is a good idea, but if the conduit costs more than the fibre then I'd question it. Multiple buildings can actually be a very good reason to use fibre instead of CAT6, even if you need to use media converter. At least if the buildings don't have a common ground ..

They didn't give you a cooling load though? With a cooling load number you can compare with cooling power of comfopost (given airflow rate). We got this from PHPP cals. From what you describe though, assuming high levels of insulation and airtightness too, it sounds like you are same as us roughly then, and Comfopost would probably be enough for some supplementary heating/cooling. If this is the case, MVHR approach is going to be easier and less obtrusive as pipes already there and no need to plumb fan coil units in. You could still put pipes in incase, but we were very confident, given calcs, that even with global warning fan coil units wouldn't be needed. We have done this only for first floor. Its worth doing now to ensure Comfopost fits somewhere and that first floor MVHR pipes are insulated. Enhabit did our cooling load calculations, MVHR design and have supplied Comfopost for us. Give me a shout if you need any more specific info.

The Comfopost is in but we aren't yet. Do you have any cooling load calculations? That's the best way to understand if Comfopost is enough or if you need to plan for fancoil. Also, what is your external blind/overhang situation like?

This was all part of the timber-frame package and that's how they do it. Not sure what the disadvantage is though, asssuming it's fixed to joists and not isolated?

Sorry I wasn't clear: - Joists - 22mm caberdeck across whole first floor. - 8mm Karma isolation strips under internal timber studs - 89mm timber studs. Between the studs: - Celecta Screedboard type product (cement-board on robust layer). Isolated from studwork. - Engineered wood flooring. Potentially with 2mm layer below.

This is what we've done - Karma Isolation Strips under paritions walls to isolate walls from metal-web joists. - Acoustic boards in each room (25mm cement + 10mm wood-fibre), i.e. not under paritions walls. - Perimiter strips to keep acoustic boards from touching studwork.

We have supplementary heating/cooling via MVHR (first floor only) and have just used foil-backed mineral wool to wrap standard 90mm radial semi-rigid ducting. The large duct that feeds the first-floor manifold (as well as out intake/exhaust ducting) uses this product which has worked well: https://www.ubbink.com/en-gb/ventilation/residential-ventilation/residential-ventilation/aerfoam-insulated-mass-flow-ductwork

Not everyone is a fan of them and they don't work for baths, but WWHRS units (e.g. showersave) can make a 300L give you the same number of showers as a 400L+ tank and will also save energy. Downside is they are around £400 each, and if all four showers get equal use and aren't near each other, you could need up to four of them.

Are they all Cupa samples? We went with Cupa R12 in the end, as they were more grey and less blue than the SSQ slates we had sample of.

I'm not sure that you can really go off house size or number of occupants, it comes down to various things that you haven't detailed: - What are you using to heat hot water? - What is the concurrent/subsequent shower requirement? - How long is a typical shower and what flow rate are you expecting?

That sounds like exactly what I need. Already gone down the Vaillant route though.. In theory they have API/Modbus/EEBus interfaces in progress, but nothing yet.. unless I try to do it myself via an ebus coupler: https://www.esera.de/shop/en/products/ebus/135/ebus-coupler-usb

Challenge with cooling can be control. While most ASHP's have a dry contact "call for heat", for cooling my understanding is you need to rely on manufactuers thermostats rather than control from home automation. Any one else have any experience of this?

GSHP for heating + ASHP for cooling, or did I misunderstand?

Another ASHP here: - The efficiency of a GSHP isn't much better than an ASHP. - Significnalty cheaper than GSHP. With a highly insulated/airitght house the payback time on extra cost of GSHP for better COP is a very very long time. - Better RHI payments on GSHP aren't worth much if you have a highly insulated/airitght house that doesn't use much to heat it to start with. - Noise on a good unit isn't much more than a fridge and it'll be down the side of the house. Prefer this to noise inside the house. - GSHP requires AFAIK more room inside the house. That said, if was building in a much colder climate then I would definitly reconsider this and GSHP may make a lot more sense in this case.

@Kesoolhe Our house is has design values of 12 kWh/m2/year for heating and 10W/m2 with 0.6ACH. But, if I adjust aritigtness from 0.6 to 6 in the PHPP spreadsheet then these figures jumps to 33 kWh/m2/year for heating and 27W/m2 heating load. With a 280m2 house and assuming COP of 3 that difference would be around something like £460/yr vs. £170/yr. Of course you house isn't the same as ours, but it gives you an idea of the impact airtighness improvements could have on the heating element of this cost. You do have MVHR don't you?

Can you do something to adjust the theshold at which the MVHR switches bypass mode on/off? The only downside of this is that in spring/summer when its still quite cool at night outside your ground floor rooms would cool down more than you'd like and might require heating in the morning that otherwise wouldn't be needed. Other option is to add some minimal MVHR cooling for first-floor only, which would mean you wouldn't need to turn on MHVR bypass when still cool/cold outside, but still be able to create enough temperature difference in MVHR supply air to get rid of the watts you emit overnight. It probably wouldn't need to run continuously but could come on occasionally based on room temperature.

Res bars is one of the best things you can do for sound, so I'd reconsider this is you care about sound rather than foam-backed plasterboard. Where have you read about form-backed plasterboard for acoustics out of interest? About the best you can do with standard wooden studwork, which gives you 59dB Rw, is: - 50mm acoustic roll withinn studwork - Resilient bars (just putting them on one side is almost as effective though at 56dB) - 2 layers of 12.5mm soundbloc on both sides. Resilent bars are cheap, and you can use standard PB. 15mm Soundbloc on either side for comparison gives you 40dB. 15mm Soundbloc + acoustic roll gives you 43dB.

Not isolated supply/extract, no. Rather just planned to avoid a door undercut on the master bedroom given the supply (bedroom) and extract (en-suite) rates are the same. I don't see how your set up is any different to any standard MVHR install though. is it?

Look at British Gypsum whitebook, it will give you all options with dB values. Both for MF, staggered timber stud and stud wall with/without resilient bars and with different types of plasterboard.

Most supplier won't do full modelling that includes things like chimmneys, and from our expeirence we didn't even have anyone model the optimzers (or not) options. Rather, quotes just used marketing statements about optimizers giving x% more yield etc. Agree with @jack though, suppliers should really give you both options backed up with data. If you have time on your hands you and want to model both options yourself (including your chimmeny!) then you can do this with a trial of Pvsol. Take some time to get a hang of it, but if your roof design is quite simple, it's not that hard. You plug in the exact location, panels, inverter, string configuration etc. as well as shading objects and it simulates everything for you.