joth

Where is the thermal envelope?

It's almost the opposite: beyond a certain level (your levels aren't quite there) adding more insulation is pointless is you don't have sufficient airtightness. Also, are you installing mechanical ventilation with heat recovery (MVHR) or using trickle vents on windows for passive ventilation? If MVHR, again you need good airtightness for that to work efficiently. (But given you are inclined to think of draftproofing as pointless I would guess you're going trickle vents.. )

The mitsubishi FTC6 has 2 zones that can have different flow temps up to 60°C and support call for heat separetely. (Or down to 5° in calling mode). If you call both zones simultaneously it will manage an electric mixing valve to temper zone 2 to be a lesser heating/cooling. (So I have zone 1 for fan coils and 2 for ufh) It also has DHW support that heating whenever the zones are set to cooling mode but that doesn't have a sensible "dumb" way to call for heat. You can force heat, but it will randomly heat on its own too based on a thermistor value. (I have used a relay to swap out the thermistor for fixed resistor values, but it's messy and really not helped by the thermistor using a nonstandard PCB header connector)

Some more https://images.app.goo.gl/ouz15L7kAKdhHbQr5 https://images.app.goo.gl/ihJT7GnGmbvFhNdd7 https://images.app.goo.gl/in2nZx6jenNkd3uB8 https://images.app.goo.gl/Jsqm7ZP3N7nYq5Wq7

Some inspiration here https://www.google.com/amp/s/blog.inviair.com/blog/linear-diffusers-why-are-they-so-popular%3fhs_amp=true With coffered ceiling it'd be more usual to put the outlet linear diffuser in the underside of the dropped section. Maybe possible to have a gap above the lighting detail to allow easy air return path to the ceiling void and back to FCU. Also, somewhere to hide the FCU service hatch?

It depends. Refrigerant based FCUs tend to have controller for the outdoor unit built in, so yes mini split AC need to be carefo matched. Normally bought as a package. At the other end Water based FCUs are as dumb as you like. Just a pipe, heat exchanger and a multispeed fan. Nothing there to call for heat from anything. Mix it with any source of hot or cold water you like. BYO controller (hint: Loxone server works great for this). I'm using mitsubishi ASHP with Panasonic (systemair) FCU and I got another unbranded one ready to install that was ripped out of a cafe renovation. In-between you have refrigerate based 4 pipe commercial FCUs. These are like the water based ones, but a bit more complex plumbing. Electrically still fairly dumb HTH.

Well the thing about linear is you can make them arbitrarily large without taking up more visual clutter. They just look like a shadow gap detail all around the edge of the room.

Having lived in both places, it's interesting how the US (where Brian is based) has a very different attitude to this than the UK. Over here it's very rare to use real names (at least, full real name) on public searchable online forums, whereas it was completely standard and expected on various US groups I joined. The whole "English man's house is his castle" is just bluster these days; we all have to hide behind pseudonyms. (TBF using a handle was always second nature for me since using CB Radio as a kid in the 80s) Anyway that's very OT! welcome Brian, I'm sure you'll have a lot of valuable input for folks here.

The essence of your question is "what size ducts, plenums and vents do I need" and the answer is "it depends on the size of the FCU and the air speed". The issue is less about draughts and more about noise and having a functional system. A PAW-FC-D15-1 fan coil has an outlet 570x220 (0.125m2) and shifts about 260 m3/h, so the air is moving at about 2 km/h when its on full speed. Put that through a 10cm pipe and outlet (0.007 m2) and it will have to go 33km/h or 15x the air speed as it does at the FCU outlet. That's going to be noisy and throttle the output considerably. But if you use 250mm pipe and a 500x100mm linear outlet (0.05m2) that's "only" 2.5x smaller than the fancoil outlet size so airspeed 5km/h is within ballpark of working ok. (Learnt this the hardway. On that FCU I originally used a 125mm outlet and it was pants. I now have 250mm ducts into a 200x1000 linear diffuser and it's great). I don't think linear diffusers are intrinsically less draughty it's just they can cover a larger area without being dog ugly. A 250mm circular outlet vent looks like a 1980s office. (A linear diffuser looks like a 2010s office)

If it's not connected to the grid, how do you power the house when the sun is not shining. And due apologies to the OP as this has gone so far off topic of EDF incompetence it's untrue. As a single suggestion to OP: I'd EDF are still messing about just get them to swap the current meter to a single phase of the new 3ph head as a stop gap until they work out how to supply and install you a 3ph meter. Good luck

If the immersion boss is in the top rather than side (more common in older tanks) you may be able to replace it with a longer one that heats the tank lower down. Theoretically you can add a secondary circulation pump that agitates the water pushing it from the outlet back to the inlet connection (just be sure to have a non return valve), which you turn on after the tank reaches initial target temp. Maybe more hassle than a new tank tho.

Why are you doing on-roof on a new build? You'll save the cost of a lot of tiles, and a bunch of maintenance headaches, by going in-roof rather than on roof. Do you have a number for total heat demand kWh/m2/year ? Walls and window U value alone only tell a fraction of the story. Floor, roof, quantity of glazing, and airtightness level all play just as big a part.

Thank you @S2D2 for sharing all your findings with this. I bought one, arrived yesterday, for DIY install in my gym/garden room currently being built. I plan to do it without the vacuum pump, just follow their alternate instructions for commissioning. At some point I'll try and hook the Tuya API from my Loxone system, but tbh we don't really intend to use it often so that won't be a huge priority. Hypothetically, if I bought it through my own company I could provide it to my household as a VAT zero rated supply and install service 🙂

There's a good discussion of it last month:

DI used more in live audio engineering https://www.palmer-germany.com/en/blog/what-is-a-di-box/

Ducting a supply vent to the bathroom seems ok except that will push wet air around to the rest of the house (to wherever the central pathway to the ceiling plenum is). Having a supply/extract pair in the bathroom would work better for airflow, less disruption to any MVHR balancing, but then you're pulling a lot of wet air through the FCU heat exchanger. This will generate lots of condensation (when in cooling) and seems likely to end up with liquid in the ducting and corrosion to the metal. I guess the main concern is for heating, in which case the ideal use is running it prior to rather during in the room usage. But that only works if usage keeps to a strict schedule. I can't recall ever seeing a/c in a hotel bathroom. I'd personally keep to UFH for bathrooms

Internal combustion engine

Hmmm they say it is "blower door tested" but don't publish the result of the test. It works like so: "This simple yet effective airtight wall vent, is opened by the air pressure of the extractor system when turned on." I can't see how that doesn't open when doing the positive pressure blower door test. Most likely they expect it to be taped shut during house testing. Also, In an airtight house, where does it draw additional incoming air from in order to expell? Putting the MVHR on boost may help that, but in which case may as well rely on the MVHR to do the extract too, per JohnMo below 👇

I'm slightly mixing up the 2 year rule for renovation vs 10 year rule for converting a non residential building into residential purpose. https://www.gov.uk/guidance/buildings-and-construction-vat-notice-708#section5 has all the details. Afaict the zero rating is not on the work itself, but on the eventual sale of the completed property. I haven't read it in detail though so hopefully someone who's been through it will be along soon to clarify

Yeah that's not a full demo so you're clearly in the refurbishment rather than rebuild rules. I suggest reading them in detail but my recollection is you need to gather some solid evidence of it never being occupied, you need to employ a single main contractor for supply+labour, and they need to see the site is unoccupied on the day that start work.

If you demolish to ground level before rebuilding it's immediately zero rated, no minimum time requirements on how long it was unoccupied. This is also easier to document/prove and also means you can reclaim vat on materials DIY installed, whereas the reinstatement of old property is zero vat on supply+labour only. (Or at least was when I looked at it in 2019) Are you doing a full demo?

Housing and heating comes off fairly lightly in that chart. It's the end of all flying and shipping that stands out as pure fantasy for me. I understand the US military and not to mention wars in general create some substantial % of emissions. You may as well plan for and end to war as an end to flying.

Did you ask them for this? If they did this spontaneously unprompted, it'd be another red (or at least orange) flag for me.

1. You need to request and pay for a new meter head from your DNO. Use https://www.energynetworks.org/customers/find-my-network-operator to find your DNO 2. You need to request a meter installed by your chosen electricity supplier (British gas, octopus, etc). This should be low cost, but can be long lead time. 3. You need to pay an electrician to install a consumer unit and outlets for whatever loads you'd like. They'll also need to design appropriate earthing strategy for a big metal building. If #3 is too expensive try asking for some more quotes. There's no shortcuts to those three steps, other than paying your neighbour for electricity supply indefinitely. Personally I'd put a single 32A ( or bigger) inlet on the container and distribute that via a small CU internally. Keep the content of the pole kiosk as simple as possible

I didn't get much further back at the time, but did recently get an autocad licence and spent some time on YouTube training videos so I can at least make simple plans with it. Not sure I'd enjoy doing schematics with it though. I might try nanocad sometime