Ed Davies

Depends where you are. In Scotland they are permitted development as long as they're at least 100 m from anybody else's curtilage. That's for microgeneration which is up to 50 kW so potentially quite a substantial turbine.

This is one of those cases you can have mixed feelings about regulation. No regulation, very small uptake, high prices so not worthwhile in terms of cost per life saved. But a few people die. Bring in regulation, much larger uptake, bit of competition, prices come down, becomes worthwhile. A few fewer people die, enough to make it all worthwhile, but a bit tough on those required to install it early on.

Agreed. I have 8 x 20 x 47mm evacuated-tube panels stored in the shed here ready to go along the bottom of the south side of the house. Bought them a few years ago when Navitron had a batch going very cheap (about half the normal price). Might only have room for 6 or 7 though, allowing fire escape from the bedroom windows, will have to measure up exact window positions given rafter placement but it's not the most urgent consideration. However, I'd put it the other way round: use solar thermal for things which have to use heat then electricity (PV plus probably a bit of wind) for everything else. It's a lot easier to turn spare electricity into heat than spare heat (especially low-grade heat) into electricity. Thank you M. Carnot. I.e., the extra capacity required beyond that needed in, say, October and March should produce electricity rather than heat. Excess heat in July and August is a pain to get rid of and possibly actually dangerous whereas too much PV is easy to deal with, put it in an electric car or leave it in the panels or…

Yes. If the plot's £10 or 15k cheaper because of the cost of getting power to it. As mine was; £35k for 2.4 hectares with outline planning permission for two houses. Also, that 4 kWh per day is bare electricity use. My house design includes a large thermal store which will need charging in the autumn to get through the coldest, dullest 8 weeks of the year. The excess of PV during that time (say from the beginning of September, or even earlier, onwards) would contribute to that so it's not just saving 4 kWh/day. Electricity here is already more than 15p/unit and will likely get more expensive over the years.

Your buildup is pretty much exactly what I'll have for the gable walls, but mine will be a bit thicker. Biggest difference is I'm thinking I'll put the vapour barrier behind the PIR to protect it. Outside in: TF200 9mm OSB3 235mm rockwool insulation between 235mm JJI I-beam studs. Polythene vapour barrier. 90mm PIR. Battened service cavity. I don't see any problem with mixing insulation types so long as, as we have, the more vapour-open stuff is on the outside.

Since December 8th my logging estimates my boiler's run for 330 hours. With the nominal consumption of the fitted nozzle (0.55 USgal/h) that's 2l/h so 660 litres. From comparison of similar numbers with actual amounts put in the tank that's probably a slight over-estimate so probably pretty close to @Onoff's 570 l. I'm a tad further north, of course, but not in the frost hollow or whatever is giving @ProDave his overnight lows.

OTOH @ProDave my average oil use (in kWh) daily since last September is nearly your weekly heating energy use in this cold period. OK, your actual heating energy use, including that harvested from outside by your ASHP, will be 3 to 4 times more but still… How confident are you of that 14 kWh/day figure? It's not your total metered use minus your metered heat pump use, is it? Subtract one big number from another and any discrepancy in the measurement gives a big error in the result. My background energy use (for router, data logging stuff, internet phone) is just under 20 W. The fridge uses about another 15 W on average. So that's about 0.84 kWh per day. The pump and boiler take about 150 W and ran 25% of the time in December (which was reasonably mild) so about 0.9 kWh/day. Laptop and monitor plus a bit of LED lighting takes the background 20 W up to 90 W so an additional 70 W for, when I'm in, 16 hours a day so about 1.12 kWh. So that's 2.86 kWh/day. The rest is cooking and the 7 kW electric shower.

Why not a wall switch inside? If there's no bath or shower or what have you in there then there's no wiring or building regulations restrictions involved. Even with a bath or shower wiring (and hence building) regulations only require that the switch be outside the zones. Some people are still a bit squeamish about having an ordinary wall switch in a bath or shower room because of the possibility of condensation on the switch causing drips into it or electricity tracking across the surface. I really doubt that'd be a problem (apart from anything else, most other countries allow them with no problem) but still choosing a proper brand from a reputable supplier seems wise. If there's just a toilet and basin that wouldn't be a concern, anyway, as there's no significant amounts of steam and no zones.

That'd do me, my average consumption for 2018 December was 4.44 kWh/day (plus burning a not-insignificant amount of oil). Depends, of course, a bit on the statistics of the lengths of the runs of power production less than that. And, as I say, your flexibility to adapt usage.

This is very much a how-long-is-a-piece-of-string question. It depends a lot on your energy needs and how much you're willing to trim your lifestyle to match the available energy. Oh, batteries are a bit low and it's not looking like it'll be sunny tomorrow, I'll just microwave this meal out of the freezer rather than baking those potatoes I planned. It seems to me that wind turbines complement PV very well. There are lots of dull days and lots of windless days but it's very rare for dull lulls to last more than a day or so.

I think it might be worth explaining the basic point of 3-phase. Say you're running a 6.9 kW device (say a heat pump) off a 230 V single phase supply then that'll draw 6900 W/230 V = 30 amps. That 30 amps will run through both the line and neutral wires incurring losses in both. You need two bits of wire into the house and to the heat pump each capable of carrying 30 amps so 60 amps worth of cable, in effect. If, on the other hand, you run that same heat pump off a 3-phase 230 V supply each phase will draw 2.3 kW so 10 amps each for which you'll need 3 line wires each capable of carrying 10 amps with the associated losses. However, if the power taken on each phase is exactly balanced then there'll be no current left to flow through the neutral; when one phase is pushing electrons into the neutral the other two phases will, between them, pull exactly the same number of electrons back out so, in principle, you don't been a neutral wire at all. In reality things might not be that well balanced so you will have a neutral but it only needs to deal with the worst case where you're taking the full amount on just one phase so it only needs to be a 10 amp wire. So, for three phase you'd need 3 x line wires and 1 x neutral wire each taking a maximum of 10 amps so a total of 40 amps worth of cable. Somewhat less than the 60 amps for single phase. In addition, in normal use the phases will be balanced to at least a certain extent so normally the current in the neutral will be smaller than that in the lines so losses will be less. This is all pretty marginal for most domestic situations, hence the controversy. Most likely you'd want domestic three phase because the DNO can only supply 80 amps single phase and you might, in some circumstances, want to draw more than 18 kW. Or, you want to feed in more than 3.68 kW without extra regulatory hassle. The basic requirement is that you can feed in 16 amps per phase, with single phase that's 3.68 kW, with three phase that's three times that.

Indeed, it's a balance. If you want a comfortable modern existence in a cold climate you're bound to do a certain amount of harm but it's worth thinking through where you'll get the most benefit, not just building out of whatever materials people in previous centuries felt happy with. I'm not advocating the use of concrete blocks in a house for heat storage. I'm saying that if you're going to use them to prop up the roof then putting them on the inside is better than putting them on the outside. Most houses have timber roofs which last long enough if the exterior is maintained. It's not a matter of the quality of the wood, it's a matter of sensible detailing and looking after the house.

https://en.wikipedia.org/wiki/Embodied_energy Concrete intrinsically has a high embodied energy because of the processes needed to make the cement. Wood is a bit more tricky as it depends a lot on how far it's transported and what other processing is done to it. It does, at least, have the benefit of sequestering a small but not insignificant amount of carbon for the lifetime of the building.

The masonry takes up space and has high embodied energy and CO₂ but gives no particular advantage I can see for that case.

Not sure where the 42mm thickness comes from, that BBA cert says 40mm. Something else I'm not sure about is whether the quoted resistances include the surface resistance with the low emissivity. I'd assume they do though I wonder how as that tends to depend on the orientation of the surface because of air movement. Maybe they assume the cavity each side is narrow enough to not have significant air movement. Anyway, you need to include the 13mm gap each side to assess the stuff fairly for equivalents so 40+26 = 66mm thick. With a thermal resistance of 1.24 m²·K/W that comes out to an equivalent resistivity k = 0.053 W/m·K which is not going to beat anything but the cheapest fluffiest light loft insulation. The thicker SF60 which has R=3.58 m²·K/W and 100mm thickness so 126mm with the gaps comes out to an equivalent k = 0.028 W/m·K which is quite respectable, better than most (all?) mineral wool and getting down towards PUR values. Maybe equivalent to EPS though I'd need to check the numbers. That's all quite reasonable. The controversies with the multi-foils came when people were claiming that this sort thickness was equivalent to 200mm or more of mineral wool (maybe 4 or 5 times the resistances given in that BBA cert) because of some sort of hand-wavy dynamic effects. Many had doubts.

So, the Comet isn't one of them?

My study where I spend most of the day is around 23°C most of the time. With a bit of cooking the kitchen warms up as well. But, yep, I have put a heater on in there to boost the temperature a few times this winter. And, yep, I'm from dahn saaf, too, Walthamstow originally.

I have three sensors made by a chap in Sofia who's, unfortunately, given up on the project and gone off to do other things. They all have temperature and humidity, one has CO₂ and pressure as well. The basic ones were quite cheap, about €20 each I think, but the one with the CO₂ sensor was a bit more, around €80 which was still pretty good as a CO₂ sensor alone can cost that much in 1-off quantities. I got the CO₂ sensor one first through backing his Kickstarter project. They're based on the ESP8266 and report their readings over Wi-Fi in various ways. I use them to send MQTT messages to a mosquitto broker running on a Raspberry Pi then have my own software to log and display the results. The actual boards and things inside are all pretty much commodity items from the likes of AdaFruit and Sparkfun or from China though I think he might have got the CO₂ sensor board made up. What was good was that he did the software and packed them up in neat little 3D-printed cases. The other week I got a couple of ESP32 boards: the newer, larger and slightly more power-hungry development of the ESP8266. With some previous experience of Arduino programming and lots of on-line resources it was very quick and easy to get one set up with a 1-wire temperature sensor to add logging of the living room temperature to my data collection.

Agree with @PeterW and @JSHarris, it's the relative humidity that makes the most difference to drying, not the temperature. I've got some washing drying in the kitchen at the moment with a dehumidifier running. RH when I first got the washing out, with some on the radiator, shot up to about 70% and the first batch took quite a while to be dry enough to put in other parts of the house to finish off. Now the dehum has got it back down to about 55% even a towel not on the radiator is drying quickly. Room temperature's only about 16°C.

Plan A was not to hibernate. Even did a bit of work on Christmas day. But there've only been a few decent days since the first week of this month and I was not feeling well for the only run of more than one consecutive one so actually I have hibernated since about the 6th. Just a matter of how the weather goes when I start again.

Looking at the GGL-9 in my rental house it's the same grub screw. The more modern ones have a little button that clicks out. I had a small adventure with fitting a Velux vertically.

Also heat capacity (“thermal mass”). I've been thinking it wouldn't be completely mad to build a house with mostly solid internal walls and timber external walls. Pretty much the opposite of what's normally done in the UK.

I've left a comment on his blog pointing here. A high or low pitched noise had occurred to me (and presumably him) but not that it might be coming from a flow valve. That might well help him track it down.

One of Paul at the end of the road's dogs is completely freaked out by the UFH. He can't work out what the problem is.

Yours @JSHarris is an SBC_01? So it's wired as figure 6.1 in that manual? But your high current supply comes via your diverter so is off when the sun doesn't shine so where does the supply for the controller come from at night? From my hazy recollection of previous conversations here and application of a bit of logic I think your wiring is actually more like that in figure 6.3 (for the SBC_02) but maybe not having the 3A relay. In particular, the controller supply I think comes in separately from the heater supply. I think the low power restriction for the SBC_02 configuration applies to the HW+iPV (not the HW+i) where the immersion is driven directly from the PV (not via the AC wiring at all). Obviously a lot of checking would be needed first but I think your system could be switched to an HW+i setup with only button pushes, no rewiring.