joth

Yeah I agree installing MVHR without the HR is a pretty silly suggestion, but no more so than taking the heat recovery energy savings as a good indication of the full system savings as I was previously doing. And MVHR without the HR was the simplest way I could think of to make a valid apples to apples comparison. You're probably right that some kind of dMEV is a better comparison but you'd have to adjust for the fact it's more to run (more filters, more motors) and less efficient (more external penetrations) than central MV to every room. Whatever I'm philosophically opposed to paying good money for windows with intentional holes in them so was never a moment of consideration for me.

Yes totally agree. Given building regs require proof of sufficient ventilation in every room they're almost mandating it (they will be just as soon as the bar gets set high enough to outlaw unmanaged ventilation)

Do you mean wrong morally, or you found something wrong with my logic? We literally embarked on the deep renovation purely to install MVHR and got dragged into the whole Enerphit project as a side quest while trying to improve airtightness to fit said MVHR. So whether it is "Wrong" or "right" I can promise you, without the goal of managed ventilation we'd have just spent a fraction of our budget doing a conventional extension and redecorate like the other 99% of house renovators "wrongly" do every year, retaining the original airtightness of a 1960s house.

No. However I would have paid more than 5p per additional marginal kWh of delivered heat over last 4 years, and predict I would pay more again on average over next 6 years Actually I just realised, the 2000 kWh / year saving is compared to having perfectly managed (mechanical) ventilation without a heat exchanger. So the relevant cost saving here is the heat exchanger itself which is £800 Inc VAT (Zehnder Enthalpic) so pays for itself in under 8 years even at 5p/kWh for extra heating. (Shorter if paying more for heat) In reality if I hadn't installed MVHR then we'd: (a) have trickle vents, (b) renovated to a much lower airtightness goal, and (c) have the windows open much more of the time, even in winter. Together these three would yield far greater (and largely unmanaged) heat losses than that what the Heat exchanger is recovering. The principle savings come from the upgrade to managed rather than unmanaged ventilation, and the heat recovery is just the icing on the cake. And I should add I've also automated the window opening and closing now too, modulating the window gap according to needs in summer, so even that is managed. That's the cherry on the icing on the ventilation cake.

No. However I would have paid more than 5p per additional marginal kWh of delivered heat over last 4 years, and predict I would pay more again on average over next 6 years. It's a weak comparison without factoring in inflation, prediction of future energy prices, and opportunity cost of tying up the capital, which ICBA to do given I didn't install for financial payback. It's O(10) years. Good enough

Thanks for the recommendation! I finally got around to watching this. Incredible. That French interior designer seemed a right knob but the rest of the team seemed a really solid crew. Bearing in mind it's all put on for tellie, Paddy McKillen especially came over really well, so hands on - sad to see he's now in a multiyear billion dollar battle with Qatari Royal Family over it all, but hey - it's tough at the top. I've been trying to find info on their new plant room architecture. Like how 5 floors below ground does Aircon work - do they still have roof mount chillers or do they dump heat to ground? Or to pre-heat incoming mains water? etc. What else does the CHP feed? What is their mix of gas vs electricity? So many questions! Searching around there's a few promo articles from suppliers e.g. on the BIM tools and recounting the impressive dig out, but not much else. It'd be fascinating to see much more into how it now all runs. https://www.linkedin.com/pulse/tech-stack-behind-epic-renovation-claridges-hotel-uk-steffen-waite/ https://www.newcivilengineer.com/innovative-thinking/ingenuity-behind-claridges-five-storey-mega-basement-01-08-2019/ https://kanegroup.co.uk/case-studies/claridges-hotel <- Promo video from M&E installers https://committees.westminster.gov.uk/documents/s20607/ITEM 04 - CLARIDGES HOTEL 47-57 BROOK STREET MAYFAIR LONDON W1A 2JQ.pdf <- the original planning app decision

I also installed mvhr for comfort rather than financial payback. But it claims to have saved over 2000kWh per year since installed so will pay for itself in ten years. The fact it uses power is negligible. It's about 3% of the saved energy. But again, it's for the comfort. Every previous house my wife would constantly be opening windows (to remove humidity to avoid mold) and I'd be constantly closing them because it was so damn cold. So I guess the biggest financial saving was mvhr has saved us a costly divorce 😂

That...... actually makes sense

Yes to this, obviously you're incurring unnecessary cost of room stats, actuators and installation if you go this route. Also in a lower (BR) spec property you'd risk one outlier cold zone calling for heat too much and driving everywhere, but the calculated heat loss suggest this is a better than BR property so most likely work just fine without zoning. (Aside - do you have MVHR and planning for good airtightness? This is likely the difference between the heat calculation methods) In some cases I find zoning useful to avoid bedroom overshoot - but the easiest and cheapest solution to that is simply not put UFH into bedrooms at all if they're upstairs. If you're sufficiently savvy then installing without zoning but with a plan for zoning should it become needed is the alternative tactic.

Sounds like a cracking opportunity for and a2a heat pump. Less power draw for more power output, and built in slow start to boot.

Did you try the Tuya mmWave offerings at all? https://www.aliexpress.com/item/1005005477612297.html much as I dislike wireless sensors, at less the £10 each they seem worth a look. it'd have to be Zigbee as their wifi models are effectively locked into dependency on their cloud service ... and some report they spam the zigbee network quite a lot. Actually... https://smarthomescene.com/blog/best-and-worst-presence-sensors-for-home-assistant/ has me looking at the Apollo Automation MSR-2. it's a little bit more ~£30 but is very interesting - native ESPHome so easy to add custom notifications, temperature built in and CO2 can be added at a very reasonable price. Just darn ugly.

2 years on, it looks like Zehnder now have an officially supported option for a local BMS/HA integration in the "ComfoConnect PRO" https://www.international.zehnder-systems.com/en/comfortable-indoor-ventilation/products/connectivity/smarthome-for-ventilation-systems/interfaces-for-smart-home Of course costs even more than the ComfoConnect LAN C, but it has modbus RTU/TCP built in. Very annoying they've in recent years they pushed FW updates to the LAN C to enable cloud service, but haven't added not modbus TCP support which would be relatively simple addition in comparison 🙄 Also funny to see "Google Protobuf public AP" listed in the table above as not supported by any device. That of course being the private API used by their app, and also used/abused by Home Assistant and Loxberry plugin to get local control over the LAN C.

So my guess... One of the main intents of BUS is to support wide scale training in domestic HP installation, hence the instance on MCS and encouraging profit taking by those with said training. Domestic plumbing is seen as a wet plumbing not F-Gas skill set and so they want people to cross train into the skills that are typically needed to maintain these things going forward

Correct, cooling is not prohibited in a bus install. The two challenges with cooling are (I) it's not allowed under permitted development, and (ii) MCS training doesn't cover cooling (MCS install being mandatory for BUS) so it's extra hard to find an installer competent to do it. In practical terms so long as you keep the cooling temperature above dew point there's not a lot of additional effort needed to support cooling.

What controls are they providing, and what do you currently use to disable/enable the conservatory zone? The one potential snag of a temporary "permanent" disconnect during the ASHP install (to reconnect after) is they disable whatever controls you have working now, and you need to redo some electrical work to get it going again. It's probably not that complicated but potentially bit of a faff for someone to have to figure out and reconnect after the fact . Anyway, the temporary disconnect is exactly what I would do (if I wasn't doing the heat pump myself, or getting a more amenable installer to do it)

Oh my oh my, welcome back! Much as I wish the reason for your return were more happy news... Your input on here was helpful for me during our build (2020/21, with all the extra challenges those years brought) I'd more than happily come over and give a hand on your replacement if you'd like an extra set of hands. Personally I'd think seriously about a uvc, fwiw.

Ok much as it horrifies me to welcome a device into my home that was previously used to monitor your comings and goings 😂, I'd be interested in this if you are letting it go. What song would you like? Feel free to DM your answer...

Is that fp2 direct to HomeKit or via their hub? (Which hub?) The advertising suggests the hub connects to everything under the sun, so a bit of a kick to hear HomeKit + frigging is required to set it up with any of those alternative platforms

Not sure that's quite right either: aiui the Green Levy applies to all three of (domestic) Gas bills, Electricity bills and Dual fuel bills. "Just 6% of a typical gas bill is from green levies, rising to 16% of an electricity bill, and 11% of the average dual fuel bill." https://eciu.net/insights/2024/are-green-levies-going-up-in-april-2024

Tell me more about the fp2 Can it send event notifications over Mqtt or a webhook? What hub do you recommend? Their website makes it out as the absolute kitchen sink of protocols but their manual and faq are offline https://www.aqara.com/eu/product/hub-m3/ I have a couple places where radar detection could be handy (e.g. the office) but one where fine grained zoning is needed (kitchen, detecting cooking vs using sink vs passing through) - I think a camera will ultimately be best there.

Great tip thank you! I got a shelly BLU recently and really unimpressed by the complexity getting it to integrate with anything outside their ecosystem. I'll grab a couple these and see how it goes The enclosure is ugly as, but seems plausible to put it into some other case.

I agree with the gist of the OP, but the discussion brings to mind a few general comments 1/ Beware of creating false dichotomies. Yes, we should be targeting homes already on resistive electric heating for upgrade to heat pumps, but that doesn't mean we shouldn't also be targeting homes combusting fossil fuels too. Both need to happen, and technically there's no reason both can't happen at once. 2/ Keep an eye on the long term goal. Sure replacing one boiler with a heat pump will not reduce scope 2 emissions for that home's heating to zero today, but the goal is net zero by 2050, not today. If it's a step towards that goal it's a step worth seriously considering. 3/ Massive scale systems change is required, not tinkering at the edges. This is a multi industry, multi decade project. Optimising each individual's personal emissions at every single step is not practical or in fact useful. What's important is on average everything trends towards net zero. Regrettable as it is, there will be examples of houses making nonoptimal choices that taken in isolation can be seen as a back step, but by moving towards renewable heat sources they are still support the systems changes needed; e.g. directing more of their ongoing spending away from gas and into electricity (and hence renewable generation projects), and supporting the economies of scale needed to reduce the cost of materials and increase training & knowledge in heat pumps.

If this is compared to an existing gas boiler, then no that's not correct. A correctly installed ASHP will reduce CO2 emissions as the COP is better than grid system losses so less combustion is needed to drive it vs burning gas directly to create heat On top of that, a portion of the electricity is from nuclear or renewables thus much lower CO2

I generally dislike doing plumbing work, and this project was no different, but it is a massive help having this chap's monotone voiceover echoing in my mind whenever I do make pipework changes. https://www.facebook.com/reel/1692555494842644?mibextid=rS40aB7S9Ucbxw6v

Do you have any room thermostats? How often are they calling for heat? If you have rooms stats, as an experiment turn them all up to maximum so the ASHP is running continuously and see how hot the ground floor room temperature gets. Then dial back the flow temperature to a level where it's just maintaining the desired temperature throughout the GF. Note the outside temperature while running the experiment, and that's one data point you should set on the weather compensation curve. Repeat when outside temperature is nicely above zero; WC curve sorted. 👍