jack

Welcome Gareth, sounds like you live an interesting life! The NSBRC used to get mentioned a bit, although my feeling is that references to it are down a bit over the years. To be fair, with over 10,000 members (admittedly most don't post) I'm sure there's a lot of posting going on that I might have seen when we were a lot smaller, so perhaps things haven't changed the way I feel they have. I'm sure you're aware of the forum's non-commercial posting rules, but I don't think you'll have any issues posting about the NSBRC as long as you keep things factual and don't try to sell anything. If you ever have any questions or concerns on this point, feel free to drop a moderator a private message (see list of staff here: https://forum.buildhub.org.uk/staff, although do try to pick a mod that you've seen online recently - we have a little shield showing at the top right of our avatar). Anyway, welcome again.

Even in a small property, I'd price it up before falling too deeply in love with this option. High quality plywood is insanely expensive. Personally, I can't stand the look of OSB. Someone was recently talking about cement board as a lining material. I think that could be an interesting option.

They work on the same principle as a regenerator in a Stirling engine. Warmer air going through in one direction gives some of its heat to a thermal material, then the airflow is reversed and colder incoming air picks up heat from the thermal material, then the cyle is reversed again (etc).

It's left on, but on a sunny day, the immersion diverter tends to keep the tank so warm that the ASHP won't come on, even overnight. If we're using a lot of hot water for some reason, or it's cloudy, the ASHP will come on to heat the tank. Also, if it's warm and sunny (especially for more than a day or two in a row), we generally run the ASHP in cooling mode during the day to keep the heat down.

It wasn't on this thread, it was on a couple of others. I assume his bland "contribution" here was to make people think he wasn't a spammer. The fact his email address included the same domain name as the website he was spamming was a bit of a clue!

The response you quoted tagged the spammer and arose solely as a result of his contribution. If it makes you more comfortable to read "[removed quoted material from spammer]" as "[removed quoted material arising from spammer's contribution]", feel free to do so.

Definitely give the scrabbler a go at that price. The grinder cost me several hundred quid in hire + wear, and that was with a discount due to my family having connections into the building hire trade. That was to do around 50 m2, although as I said, the concrete was old and hard. Treat yourself to a decent respirator too, if you don't already have one. Concrete dust is bloody evil.

I assume you can't just build up with adhesive, because the concern is more the loose crud on top than a little bit of unevenness. If all you want to get is to get rid of the loose stuff on the top, I'd have thought a scrabbler would be the way to go. I used a concrete grinder to grind the concrete floor in our garage (we had spalling for various reasons - very cold weather overnight, possibly a bit too much water in the site-mix that was used), and would caution against it. To remove only a few mm, I had to go over it repeatedly, and it cost a fortune in worn diamond pads. Admittedly I was working with concrete that had cured for several years - if your slab is days rather than years old, it'll likely be easier on pads. But the main thing here is that you aren't trying for a smooth surface, you're looking to break up a thin friable layer. Scrabbling is much better suited to that task than grinding. I wouldn't worry about grooves being left by the scrabbler. If anything, they'll provide some tooth for the adhesive.

There's no hard and fast rule - HMRC basically does what they want, and in general that involves rejecting things unless there's a clear case to the contrary. Personally, I suspect there's no way you'll win an argument that you've installed a grand's worth of speakers to hear a doorbell.

I skimmed through that this morning and wondered which BuildHub members were involved.

Welcome to BuildHub. No reason it can't work. We had the same thought when we saw what the cement board we have in a few places looked like (before it was tiled). You could buy a piece and experiment with different finishes. I'm sure you could make it look more interesting with a waxed or lacquered finish, or even ragging or coarsely thinly/randomly trowelling on some tinted plaster or cement. Even some offcuts that we left outside developed an interesting patina after a few rain and drying cycles.

I remembered less than 20 mins ago - bloody phone was somehow on silent so I didn't hear the reminder! Ran around and turned off what I could, but have just now learned that the washing machine has been on the whole time as well. Also, it appears the car's been plugged in to charge until right now (partly my fault - we came home together, my wife plugged it in while I got the dog out of the boot. I'd planned to put it back onto the cheap tariff so it wouldn't start until after midnight, but I got distracted and didn't do it). If anything, we're going to have used more than our average consumption during this period. Bugger.

Not really. The most common mistake is to use kW where kWh is intended, but kW is often used appropriately too. I don't think AI is at the stage where it could handle the distinction perfectly, but even if it were, the forum software isn't capable of doing this.

From the original email introducing the scheme: We seem to be roughly on target for that order of magnitude, especially taking into account the late start to winter.

Perhaps sit on BuildHub typing "The correct unit is kWh" over and over?

I'm somewhere north of £8, nearly all of which was over two sessions.

Should be fine. They always seem to end up with a few bent fins one way or the other.

You really need to know the heat losses to determine the appropriately sized heat pump. For a house with excellent insulation and airtightness, you could comfortably get by with a 5 or 6 kW unit. Several on here have done this successfully. If you're planning minimum insulation and not paying attention to airtightness, you could well need a hell of a lot more.

Great news!

I agree with the general thrust of your comments, but the problem isn't "impossible", it's just going to take a generation to sort out. People said that about operating a computer 40 years ago but look where we are.

Yes, and it gets worse as the temperature reaching the mixer falls as the tank empties. For those not familiar with how this works, the issue here is that you're effectively using the heat of the drain water to preheat incoming cold water. The "System B" approach involves you only heating the cold water feeding the shower. The closer the incoming hot water to the shower is to the target output temperature, the less cold water you need to mix in. The edge case is where the hot water is supplied at the target temp: in that case you'd get no recovery, because you don't need to mix in any cold water. It's not all bad. If you're using less cold water, then what you are using should have plenty of time to absorb heat as it passes through the unit. Since it's warmer, you'll need to mix in more of it (and hence use less hot water) to keep the mixer at the desired temperature. I can't remember which way around they go, but System A and C involve preheating the cold feed to hot water tank, or cold feeds to both the tank and the shower. Preheating both can offer higher recovery rates - probably quite a bit higher where the average tank temp is lower due to being heated by an ASHP rather than a gas boiler. Annoyingly, I allowed our plumber to talk us out of connecting the cold feed to the DHW as well as the showers, due to complexity. For others reading, it's imortant to go for this type of connection if you have a low temperature DHW source such as an ASHP. One other thing: other than through the worst of the winter months, our immersion diverter often heats the tank well above what the ASHP is set for (50 degrees at the moment). On Wednesday, for example, the tank reached 63 degrees. In that situation, we do get more waste water heat recovery. Obviously this is much more common outside of the dark winter months.

There is no technical or practical reason why it needs to be a disaster. ... but based on all evidence of what happens when government and/or big business tries to implement complex things for civilians, yes, the net result would be disaster.

We have a 5 kW ASHP in a 289 m2 house with PassivHaus levels of insulation and airtightness. It does fine, although during this time of year, it'd be great to have a higher maximum output so we could do more with the 4 hours cheap period we have on Octopus Go.

Absolutely go for 300 L (minimum). We have a 4 bedroom house, and with four of us (including two teenagers) living here, our ASHP-heated 250L tank can struggle some days, even with waste water heat recovery on the two main showers that are used. Admittedly that's partly because it's programmed to only reheat water during the Octopus cheap period from 12:30-04:30 - we'd rarely have an issue if we reheated continously, or at least during another period (couple of hours in the afternoon, say). It sounds obvious, but the larger the tank, the more energy you can store at a given temperature. It probably doesn't make much difference if you have a gas boiler that can get the water up to 80 °C, but it you're maxing out in the 50-55 °C range like most heat pumps, that's a drastically smaller amount of stored energy. If I were doing it again, I'd go with a much larger tank so I could heat it to an even a lower temperature. That would both help with COP and reduce standing heat losses. Do look into waste water heat recovery. It might add ~£1000 (installed), but it'll signficantly reduce the amount of hot water your showers use for a decade or more without maintenance. I was absolutely certain that you had to meet both, but you're right, it's one or the other. Every day's a learning day on BuildHub!

Ha, no, but my neighbour is a cameraman and has a massive drone he uses for work. Might ask him to get some shots next time he has it out in the garden.