joth

@NBW for the high end spec you appear to be building to, I'm surprised you're not aiming for high airtightness and hence MVHR? As well as removing the need for per-bathroom extractors it would help with the room by room heating balancing you mentioned as a goal. (Not so much due to the MVHR moving heat around, more by applying a whole-building strategy to thermal envelope and airtightness design)

Yes that's correct, my comment was speaking to @JamesPa point that MCS are the (sole) guardians of the standards, not regarding certification perse.

No chance this changing any side soon: aside from BUS, MCS is also mandated by law for permitted development rights for ASHP install. And notice the wording on this is changing in May 2026: previously it allowed for MCS 020 or equivalent standards, but from May it it MCS 020 compliance, or no heat pump for you. (Obv you can still go the PP route, but what LPA is not going to slap the MCS020 requirement on their approval). https://www.planningportal.co.uk/permission/common-projects/heat-pumps/planning-permission-air-source-heat-pump - Oh, And I love the way the "MCS 020" link sends you to a 404 not found error on the MCS website. Pretty much highlighting the exact perils of public law referencing a private corporation (charitable trust) as the monopoly gate keeper for standards. Still, I guess it's no different to IET owning the wiring regs is it? Well, except they do at least step up and define the regs and the methods for the most part.

That's definitely a monobloc and those are definitely water pipes. Insulation is required by part L and by MCS MIS 3005, which I presume is why city plumbing think it's OK to charge over 200 notes for a pair of flexis https://www.cityplumbing.co.uk/p/pump-house-ashp-flexible-hose-750mm-female-114in-fh-750-2-114-f/p/648052 EDIT F*** me! I think that's the price for a single flexi, so > £400 for the pair. I'm in the wrong business.

I've used them a few times when a room needs more expansion than I can fit on a standard cat 6a drop. My ususal approach is one cat6a home run per room. Provides power (orange) tree (green) and 4 discrete digital ins (blue + brown pairs) for retractive switches, basic motion sensors, window/door contacts. If a room needs >4 DIs I either split to 2 zones and have 2 home runs, or put a Nano DI at the first drop (e.g. main light switch back box or main motion sensor) and wire all the other DIs to that. You can even get funky using the 4 spare cores the panel plus a Nano to provide 10 DIs per room... but you're creating a maintenance headache for anyone wanting to alter it in future. A really consistent approach would be on (or more) nano per room, in an obvious location (I like the ceiling motion sensor as easy to fish wires to and lots of wriggle space behind it) and pull all the digital devices to that for the room. The layout of the house impacts the decision a bit -- if the panel is super central and easy to wire into then why not do it all central. But retrofitting a 5 story Victorian townhouse - different matter and a more distributed approach makes much more sense.

I believe you can mix and match and active (master/slave) sub into an otherwise passive audioserver speaker set. As an added benefit it gives you a Bluetooth streaming receiver for the room the sub is in. (Which maybe more accessible/familiar for guests) - at least, they said this works on the loxone partner training when Master/slave was being announced. (I pointed out at the time that this master/slave terminology was tabooed in USA at least in the 90s as non-PC, which is why USB made a late change to Host/Contoller terminology just before the 1.0 spec published. I guess Loxone either don't care for that market or have their own ideas where popular sentiment is headed ) Fwiw i like stereo pairs in any indoor room i care to have music in; I use bookshelf speakers in most rooms. Fancy Logan Martins with sub for the TV. A few concealed Monitor Audio wall mounts. No ceiling speakers as i just don't like the sound from them. But also i just use AudioServer as an spdif source, and use an Anthem MDX-16 amp (install predates the new audio server, and the Anthem is a totally different level) If installing now I'd probably put a ceiling speaker in hall and landing just for announcements, instead of the grim burglar alarm sounder

I'd imagine they're over specifying it as everyone does in audio. Gold plated connectors and all the rest of it. It'll work fine on 1mm if you have to, but if you're running the power 5m between cabinets to the audioserver I'd be inclined to cable anyway, it's not going to make a measurable difference to the project cost. Interesting experience @Kelvin with the TP link. I've only ever used audioserver with unifo router (3 installations) so can't comment other than confirm I never saw those symptoms. The main issue I've dealt with is flakiness with AirPlay discovery and control. But I don't use that myself

Be careful about the distance from WLED controller to the tape. As well as the usual voltage drop on a long line, it's also prone to interference. For example the WS2811 guideline is 10m maximum, but some people have problems even working within that

Jeez I've be telling y'all to give it a try for 5 years and the response is always Raspberry Pi blahblahblah (i stop listening after the first word) I've built or flashed esphome onto a couple co2 monitors, energy monitor, wled addressable strip light controller, radar motion sensor, 1-wire interfaces, a few modbus gateways, openevse car charger, various smart light bulbs and wall socket relays, probably a bunch other things i forget now lol I need to work through updating them all to esp32 though as the older esp2866 doesn't have enough flash for the standard stack of components I like to include in the build.

I also have a trade account with Future Automation in case anyone needs help with ordering

My car was sold as having a top speed of 140mph but I very rarely use that.

Interesting. i saw the Deege reference on the website, but AI did a better job of doxing the individuals connected with it. (Yay thanks AI) Deege did my battery install (and forgot to bill me for it for over a year lol), so the name did jump out. They're Kent based.

I fell over on this line lol. Who or what is WonderWatt? I mean, obviously it's this website: https://www.wonderwatt.com/ But their contact and about pages don't mention a company name/number, the the ToS doesn't even mention which country's law it is acting within. I'm curious where I'm sending my data if I sign up, but statements like "We will process your personal data in accordance with our Privacy Policy and in compliance with applicable data protection laws" are meaningless without stating who or where they are, and which country's law they are following.

But an mvhr unit has no way of measuring how much energy the building would be using on heating if it was to be used under some other hypothetical conditions, such as if it were turned off. It has measurements for air flow rate and incoming/outgoing air temperature so the only thing it can realistically tell you is how much energy it has recovered from the outbound air in the operating conditions it is actually working under.

Compared to running the fans but without any heat exchanger. What else could it be? This is obviously not a comparison of a leaky house vs airtight with mvhr, but as an mvhr designer it's the only sane number to provide, given the instrumentation available to the device.

According to the status page ours is reducing our heating demand by about 2000 MWh per year. So something like £50-400 per year savings, depending how much you pay for heating energy. But hard to place a figure on the air quality, cleanliness and health benefits. That's the primary reason I installed it, rather than for a bottom line cost saving

Haha well remembered - yes that is a problem we have in our house, but not one I've tried to solve through simultaneous ASHP heating and cooling. (Although a w2w heatpump would indeed allow pumping excess heat from the FCUs upstairs back down to the UFH downstairs) My solution is during the heating season, the ASHP is in heating mode only (for the UFH) and the bedrooms have additional fan bringing in cool air from outdoors as needed (essentially an MVHR mega-boost mode). This air intake fan shares duct work and electronic dampers with the FCU network.

That's a neat in-roof install method, great to see new innovations for making neat and cost efficient installs. ( I say new, maybe this is old hat but it's 6+ years since I researched RIS for my own install) Using battery to smooth out export within your export cap is excellent idea, but doing so optimally is an interesting problem in sunshine and price forecasting. Do you already have tech solution in mind for that?

Did I? I forget where i might have said that. Certainly, that's not the system i ended up with in my own home; we have a single 2 pipe monoblock

Funny enough the last electrician that worked on my CU (in 2024) complained it must have been installed (in 2021) by someone old school as black was sleeved as blue, and the modern convention is to eschew black as neutral. I just smiled and nodded (perhaps with a shut up and do what you're here to do vibe)

I have done both, and shared some views here earlier today TLDR separate AC is lower hassle if getting someone else to do it. All in one ashp is neater and probably cheaper, but you need to be even more the ball managing or DIY installing it

@SBMS 24kW cooling load?? If you're serious about meeting that, forget underfloor cooling and water heat pump, it won't delivery that. Talk to a commercial refrigeration expert Specifically: a 12kW heat pump will typically have a bit lower nominal cooling capacity (depends on model), but will have much much lower practical capacity unless you run it at around 5°C, with all the heavy condensation issues that brings up. UFH can't safely be run below 12°C minimum, and even then has lower effective emitter power in cooling than heating due to lack of convection currents. So I'd guess you'd get 4-6kW max effective cooling. At best you can run some modest cooling from the ashp in addition to an industrial sized A/C system to help support it. Good luck.

Also have a look at radiant panel cooling. Like FCU this is popular on the continent but less so in the UK. But apparently works very well for fanless cooling. Happily this has recently been relaxed for detached houses. Physically finding space for two outdoor units can be a pita though, a definite benefit of going single unit.

As a counter point - I did the single ASHP with heating and cooling system in my own home, and overall it required more dicking about than the two separate systems I've setup controls for in other homes. Admittedly, I did mine in 2020 when there was less information available on how to do it. (And, global events were making doing anything more difficult lol) So on balance, if doing it again then I'd do the same (single ashp) using the knowledge I'd gained. But if advising a friend (who isn't technical / isn't going to be hands on in the install) I'd probably advise separate systems unless I'm happy to hand-hold them through the whole process

This is exactly not my experience (Enerphit passive house). Heating you can batch input, a few hours will allow the building to coast through the day. But cooling needs applying in the occupied room, when it is occupied. We sleep with the door and window closed (for noise control), and a couple humans output enough heat to cause the room to overheat even in winter. I said noisy in comparison. I have ducted unit so can't directly compare, but the ducted unit is near silent - no noisier than MVHR - unless running at full tilt. Indeed, I ran the condensate pipe anyway as why not. My point was if paying someone else to install, forgoing this will help eek in under the grant cap. If the BUS funded ASHP is sufficient size to supply all the whole property heating needs, and the AC is there purely to supply the cooling needs (which MCS don't cover in their design guidance anyway) then logically there's no conflict. What the installer and/or someone arbitrating the legislation would rule I don't know.