Dreadnaught

Good point. I forgot to mention PoE. Keep in mind that a PoE injector is included in the box with every AC Lite.

Probably. If you intend to run multiple devices from a single ethernet wire (e.g. CCTV camera and an AP) then all you need is for the cable to plug into an ethernet switch first, which acts as a junction box. There are loads available but something like this would do: Also keep in mind if you are without an ethernet network that you can use Unifi AC Lites using Powerline through your electricity wires. I don't have much experience of Powerline. I hear it can be a glitchy but it certainly can work.

Oh and one last thought. I would imagine in this day-and-age and for an HMO, complaining about WiFi will be a perennial pastime for your tenants. I would think that investing in a good Wifi system (ethernet wired, not wireless, and mounted in the ceiling away from prying hands) would pay-off many fold. Add in remote management and you have solution that could well make your life easier. Not to mention that good WiFi could be a selling point for prospective tenants. In your case, I would avoid consumer solutions and instead go for a commercial solution like Ubiquiti Unifi. Its widely used professionally, including for large deployments. Every professional installer you speak to will know all about it. It takes a little getting used to be once setup its really just fit-and-forget. You can DIY-it easily. And its not expensive. Just a thought.

Oh, and wifi extenders don't really work because roaming fails. The multiple dumb routers do not hand off the WiFi connection between themselves. The user ends up connected to a distant router when a better one is nearby but neither the router nor the connected device does anything to remedy the situation. (And that is to ignore the reduction in transmission speed of using a single frequency for both extending and data transmission.)

Best solution, if achievable in your circumstances, is Access Points (APs) connected by ethernet (not wireless). APs ideally should have seamless roaming, like Unifi AC-Lite (below) or similar. They are not very expensive. About £70 each. If you go with that approach, you don't need anything else. You can turn off the wireless transmitter in the modem provided by the internet provider. It does take a tiny bit of technical knowledge to set up such a system up but I assure you that its very easy and there are people on here who can troubleshoot for you. For an HMO, you can also manage the network remotely with a little extra cost (about £70). An example of a suitable AP (you would need at least two):

Welcome, a very interesting build. We like photos

@dnoble did you see the design and installation manual here? http://www.bublshop.co.uk/files/pdf/pdf2040.pdf. (Credit to @le-cerveau for the link, https://forum.buildhub.org.uk/topic/2845-sunamp-heat-battery/?do=findComment&comment=102379)

@Ed Davies that's a good point. It reminds me of @TerryE's comment in his excellent posts about using the slab as a heat store posted in Boffins Corner. He mentioned that the low-wattage UFH circulation pump was over time fundamentally just another kWh of heat going into the slab.

Interesting. I suppose the use of such a system does present a conundrum. With a well-insulated airtight house of modest size (I don't know if that is what you are considering), the energy demand for space heating is rather low. Energy demand for domestic hot water can often be similar of higher than for space heating. But a heat pump struggles to generate heat sufficient for domestic hot water (DHW). A 34º SunAmp preheat solution for DHW is one solution. Or a multi-stage heat pump but then the CoP suffers. I assume this would also apply to a w/w heat pump. Might you have access to much more energy than you need? Or perhaps you are considering a less energy-efficient home and therefore could use copious hot water at 34º for space heating? I assume a w/w heat pump would however offer a few advantages as well as access to copious energy, much better CoP in summer and winter compared to an ASHP for cooling and heating. (And there is the question, of course, is if the extra cost is justified for the benefit.)

Why is that, I wonder? It is because the system is always optimised for heating? If so, I wonder how.

What a lovely location! I am curious, how would this work in practice? Would the blades be in the bed of the main river? In a rivulet? Or might the water by piped from the river and back through a tank (or some such contraption)?

@canalsiderenovation, I tracked it down. It wasn't Grand Designs, it was this: https://www.houseplanninghelp.com/hph182-extracting-energy-from-watercourses-by-generating-electricity-and-extracting-heat-with-justin-broadbent-from-iso-energy/ Extracting energy from watercourses by generating electricity and extracting heat – with Justin Broadbent from ISO Energy. A podcast by Ben Adam Smith, the House Planning Help podcast. Have you listened to it?

I am sorry that I cannot help you directly but what a good idea! I recall seeing an implementation of this on one of the property programmes (was it Grand designs?) and it worked very well.

I have visited the author in his recently finished new house in Cambridge. The house is designed by a top (and very expensive) architect, has a fabric-first approach, and looks splendid. A frivolity he was keen to show off was a 3-metre powered opening glass roof panel.

In the most recent Passivhaus Trust newsletter (link below) is a link to this document, "Good Practice Guide, MVHR for single dwellings". Its a detailed description of how to design an MVHR system for a Passive House. The guide: http://passivhaustrust.org.uk/UserFiles/File/Technical Papers/2018 MVHR Good Practice Guide rev 1.2(1).pdf The newsletter: https://mailchi.mp/passivhaustrust/pht-news-sept-18?e=894c841f59

It was Charlie's co-presenter, the designer Aidan Keane, who passed away, not the house owner.

Just watched it, @Hecateh. What an achievement in such a good cause! 9 days, wow. Thanks for sharing.

The Passivhaus Trust has announced that the number of certified Passivhaus units in the UK has topped 1000 - with at least as many again in the pipeline. http://www.passivhaustrust.org.uk/news/detail/?nId=787

Keep in mind that the window frame has a much lower u-value than the glass, whether 2G or 3G, and the frame can represent a surprisingly large proportion of the total face. Perhaps focus less on 2G v 3G but look closely at the frames.

https://www.linkedin.com/in/charles-hamer-70254111/

And what's the decrement delay of spray foam in comparison with EPS or blown cellulose? A useful question @Russell griffiths?

This is a good podcast on airtightness. Some of you may know Paul Jennings, a professional air tightness tester. Some interesting comments about different building systems, tapes and tips on taping. Interestingly he named two tape brands as being the best: ProClima and Siga, with ProClima being slightly better at dealing with self builders. https://www.houseplanninghelp.com/hph227-whats-the-best-way-to-build-an-airtight-structure-with-paul-jennings

@Hecateh Do you mean the "The Big Build - Isle of Sheppey" episode? https://www.bbc.co.uk/programmes/b08tpkpb

@PeterStarck When you said "higher levels than the minimum PH level" did you mean to say that or perhaps "higher levels than minimum building-regs' standard level", or some such, instead? I am planning to go to PH levels of insulation but not beyond.

Brick slips. Thanks Peter, corrected.