jack

Especially when you were aiming for the moon.

We have that general arrangement and it's fine. The only minor issue is that it's a long way to the loo in the middle of the night, but that's not the end of the world.

Yup, agreed, but I've definitely read at least once on BH that supply vents should be high up.

My floor-level vents are in the bedrooms, so they're outlets/supply. I've heard it suggested that a higher supply position helps ensure that the fresh air being introduced diffuses better, but I'm really not that fussed. I don't notice any difference in air quality in these rooms compared to others with ceiling-mounted outlets.

Wow, didn't see that coming! I had plans to order some glass from them in a few weeks once the weather improves enough for me to finish the fiberglassing on our balconies. No idea how liquidation works, but is there a potential opportunity to buy fixtures and fittings cheaply from the liquidator? Naturally not bespoke stuff like glass panels, but all the mounting bits and pieces.

We have floor outlets in the bedrooms for our MVHR system. They seem to work fine

Oddly enough, I was reading about this again just the other day. They apparently degas the lake somehow to avoid this problem arising again. There's at least one similar lake somewhere in Africa.

In a house, CO is the real danger molecule, partly because it doesn't cause a fall in pH (and hence your body doesn't recognise that oxygen is being squeezed out) and more importantly because red blood cells strongly bind CO and tend not to release it. I believe the latter element is why even apparently low relative levels of CO can be a problem if you're exposed to them long enough.

So crack on then. Let us know what you come up with. One factor to consider is that solar thermal is eligible for the RHI.

You can also run UV sterilisation.

This is such an exciting part of the build process. I hope it goes well for you. I think it'll be really satisfying assembling all those blocks - it's like the biggest Lego/Ikea project ever! I hope you'll be disinfecting the water before using it in this application.

You're welcome.

You know they're doing this, right?

You replied to a comment about it becoming cheaper to recycle lithium by saying: That is, you are way off point. Feel free to have the last word - I'm out.

Yes, the way we consume things is unsustainable, but the rest of your post is completely off point.

That's hardly the same thing. Used lithium is still fundamentally lithium. Used nuclear waste is an entirely different set of atoms.

That's the current situation - as you say, it's a finite resource, which means it will ultimately become more difficult and expensive to extract. The rising price will push research into recycling, so that will become cheaper and more efficient. Of course, by then, we may have other storage possibilities that reduce the demand for lithium batteries.

I'm sure it could be done more cheaply with a Willis heater, but for not that much more money I agree that having everything in one integrated and warrantied unit is attractive.

A Willis heater is an inline system, no tank required. You could use a small tank as a buffer if you wanted to. You'd need to check with a plumber as to whether an expansion tank is required given the volume of the system.

An ASHP is much, much cheaper than ground source. For what you're trying to achieve, you'd be buying the smallest possible unit. You can probably get something for £1700-2000, depending on brand (you might get it cheaper if you're willing to go the ebay route). Installation isn't too hard, and with an installation this size you can probably avoid a manifold + pump (etc) and have the ASHP drive the UFH directly. I do worry that even the smallest ASHP will be so oversized that it will be cycling on and off a lot. Edited to add: ASHPs are fugly, for sure, but usually you can tuck them out of sight. The issue you'll have with your situation is that you can't put it at the back or side of the building, because there's no space. You could put it at the front, but you'll need some form of screen to camouflage it. I wouldn't worry too much about noise: if you're using it, the doors/windows will be closed, and decent inverter-driven ASHPs really don't make very much noise, especially when they aren't being driven very hard (as would be the case with your setup). Given how low your heating requirement will be, I'd really think hard about whether it makes financial sense to go for such an expensive heating option for a space like this. Alternative idea: @TerryE plans to use an ASHP with UFH, but is presently experimenting with a Willis heater to get a feel for how much heating he actually needs. A Willis heater is basically a standard immersion heater in a sleeve, which heats water as it's pumped past. It's incredibly cheap and simple - eg, here's one for less than £50. You'd need to add an UFH pump to this, but it's still a lot cheaper than an ASHP. They're very reliable, and if it breaks you can buy a replacement immersion heater off the shelf for peanuts. In comparison, we had a pump go on our ASHP after less than three years and that cost several hundred quid to replace (had to replace a circuit board and pump together). In your situation, I'd consider a Willis heater driving a radiator or underfloor heating, and wiring up (but not yet fitting) provision for an air conditioning unit that can be retrofitted if you find it regularly getting too hot in summer. You could spend the money you were going to spend on an ASHP on better insulation (as mentioned above, timber frame is definitely your friend given the space constraints), which will further lower your energy requirements. Pay attention to shading so that you maximise gain in winter and reduce it in summer.

Our plumber nearly choked when I told him we were considering a 5-6kW unit for our 290m2 house. He wanted to install a 15kW ASHP as a minimum. His main concern was how cold the house would get during the 1-2 hours that the ASHP would be heating the cylinder early in the morning. In reality, it takes something like 24 hours for the house temperature to drop by any significant amount!

Absolute worst case, some form of resistance heater can always be employed to supplement the ASHP output on the very coldest days of the year. For example, judicious use of a fan heater would be a low capital way of topping up any shortfall. By way of example, we got by through all of last winter with a 1.5kW column heater in our kitchen after our ASHP packed up. I should add that this was the only proper heat source we used to bring the house up to nearly 20 deg C from the 14.5 deg C it reached while we were away for three weeks over Christmas 2017. Sure, I would have preferred parts of the house to be warmer at times, but it wasn't the end of the world.

We have the same. Wouldn't be without them, although I don't bother with the solar tracking function. As for light, I don't generally close ours fully. You only need to stop the direct light, which is nearly always achieved with the blinds partly closed. Enough reflected light still gets through to light the room. Nothing keeps the heat out better than external barriers in my opinion. Our bedroom faces east, and unfortunately it's the one place we should have specced blinds but didn't. We have thermal fabric up but it gets hot and radiates into the room. I wouldn't rely on it as a way of keeping a room cool if it gets direct sun.

That was me on the weekend (minus Faye). Great weather to be up in the mountains having a cold one.

Find me a better selfbuild forum on the web. I'll wait...