Radian

OK, sounds good. Still recommend you use a warm roof build-up which will make up for some of the losses from the glazing. Also simpler to construct and insulate. Velux or equivalent would work but do you even need opening roof windows? There doesn't seem to be much in the way of fixed glazing for sloping roofs but I don't understand why. Would have thought it would be a popular, cheaper alternative.

Hmm, from this manual Lights table Mains Light Green Power is on Red The unit is in standby mode. Check troubleshooting suggestions. Sensor light Green Surplus power is available Red The house is drawing grid power Flashing red/green ALL available surplus power is being offered to the immersion heater circuit Immersion light Green Power is being offered to the immersion Off No power is being offered to the (?) Flashing red Boost function is operating No mention of amber anywhere. But that's what it seems to show at times in your video?

Not sure about pent roof. Do you mean with the highest side adjacent to the garage? Is it your garage? I think I'd go with a flat roof (warm buildup) and plain rectangular skylight. Any reason you're not using the full footprint of the old conservatory (3m)?

No direct experience with that module, other than that I'm currently trying to understand the Vaillant/Glowworm ebus protocol which the VR33 module bridges to OpenTherm. I've built the electrical interface and got it talking over a connection to a RaspberryPi running ebusd. In principle, once this is working, an OpenTherm interface should be quite easy to knock-up.

Interesting reading. From the article you linked: "This means much smaller boilers (in this case 12Kw) are needed so no gas pipe upgrades." I'm looking at a possible boiler replacement for a 30kW condensing heat-only one. I've already tried range rating it down to 15kW which is more in line with my heat loss calculations and barely notice any difference so I'm looking to replace with something having half the capacity. My current boiler has a 15mm gas feed and is only 2m from the meter connection point and I'd rather like to retain the feed pipe as it's neatly hidden behind tiles. I had been anticipating the imposition of a new 22mm gas feed which seems to be automatically installed with any new boiler these days (judging by experience of other recent installations I've seen) but this article makes it seem as though it might be possible to retain the 15mm feed?

Jeez! It's only XPS as well 😵 for that kind of money I'd want aerogel.

Probably for the best if it's not your money or your boiler. Actually that's given me an idea. I have a double panel rad with only one side that gets hot. I was going to wait until spring to remove it and flush it out with a hose outdoors but it'd be a little easier to isolate everything else, open a drain valve and put mains pressure water into the fill point. Or maybe not such a good idea to release crud into the rest of the pipework?

I have to say I'm a bit confused by your question. What difference does it make what fuel the boiler uses?

My installer used Evobead as well. I tried analysing them with a megger to see if the graphite gave a measurable resistance but they didn't show any conductivity up to 1kV test voltage at least. I'm pretty sure they do conduct a little at static level voltages as they don't tend to cling in the same way plain EPS beads do.

Especially in the bathroom(s). I'd apply more than one coat.

Quite high. The vertical membrane looks to be folded over at the junction between plasterboard and wall plate suggesting that the vapour barrier is directly behind the vertical plasterboard in the rooms below. If the overlap is an attempt to prevent cold air getting down behind the vertical plasterboard it fails as there's nothing sealing it to the wall plate. I.e. it can't fold over in both directions.

Collar tie. C channel or anything mounted parallel to the ties is going to work. Our attic trusses were all over the place and got sorted by screwing a whole bunch of 2x4 like in your illustration.

This is why I worry about the practice of using a vapour barrier beneath loft insulation. In theory, if the insulation is doing its job and keeping the ceiling at room temperature, then no condensation should develop between the plasterboard and vapour barrier. But in practice, despite there seemingly being good levels of insulation, any shortcomings with it will lead to this kind of problem. The overlapping membrane may be intended to prevent cold air from the loft descending the wall rather than providing a fungus garden so I would want to understand the build-up before cutting it back. The problem I see with this suggestion is that there's nothing preventing the build-up of vapour coming through the plasterboard which is not foil backed. Sealing with airtightness tape could actually make things worse. The adjustment I would make to this solution would be to trim the membrane back to the end of the plasterboard and seal the junction to the wall plate with Illbruck FM330 Air Seal foam.

If the loft insulation was sufficient to prevent the plasterboard ceiling from getting cold the condensation wouldn't be forming. Could it be that the extract vent pipe was keeping this area from being properly covered? If you pulled back insulation from another similar location at the eaves would you see the same problem?

The fact that there's a "cable" connection between the display unit and a "cable" dispenser reel must be the giveaway. I use scare quotes around "cable" because it might not be electrical. But if its a flexible tube containing liquid or gas I can't figure out how that could work. But on the other hand, if it's an electrical link, why didn't they make it wireless and have unlimited range between the two ends? I'm beginning to think it's atmospheric air in a tube with an extremely sensitive pressure transducer at each end.

What's the working principle behind these? I'm at a loss to guess. You say accurate to 0.1mm but the picture shows a precision of 0.01mm (the width of a sheet of paper) which would be truly remarkable.

It depends on how you use your HW though. Early morning showers at any time of year will require the import of power and in the winter this may leave the cylinder close to full. It's just not easily predicted. If there is any spare PV, a cascade priority system such as this makes perfect sense to me.

It's a sobering lesson for anyone not understanding what interstitial condensation is all about. Downlighters, no vapour barrier, poor insulation. No doubt it all looked fabulous the day it was done but the consequences would soon begin to reveal themselves and the whole thing probably became a constant worry for the original owner. Looks like @MattMiller 's gonna sort it out 😃

GPS suffers from Dilution Of Precision due to the changing geometry of satellites as they orbit relative to ground locations. Altitude error is generally specified as having 1.5 times the horizontal error - which itself is in the order of a few meters. Your results are surprisingly close! I'd say more down to luck than precision and accuracy was probably way off. You can do much better by measuring air pressure. Very roughly speaking, referenced to an air pressure of 1000mb at sea level, pressure falls reasonably linearly to 500mb at an altitude of 5000m (with half of the Earth's atmosphere sitting below this altitude) so pressure changes by around 0.1 mb/m. A typical digital pressure transducer is only precise to this sort of amount so you could only use one to estimate height to within 1m steps. A fancy one might improve on this by a factor of 10 but would be difficult to get repeatable measurement's from it.

Neither altimeter or GPS are going to be any where near accurate enough. Maybe to the nearest 2m but that's about it. I don't quite understand your problem with the laser level but a water level kit might help: https://www.screwfix.com/p/water-level-kit-15m/3573v

It's right there, in the name. 🤣

I had begun to contemplate how to measure air movement inside a cavity to evaluate efforts to improve airtightness. My current thinking is to build a small solid-state anemometer probe inside the end of a small diameter copper tube. This would then push into a hole drilled through the inner or outer leaf and sealed up afterwards.

This question often keeps me awake in the night. If all the insulation value of EPS beads was lost due to airflow then why would anyone bother with injecting it into cavity walls? Obviously the volume of polystyrene displaces the volume of air by around 70% so the potential for heat transport is reduced as would be the mean velocity. But this is only considering the displacement effect of the beads. The expanded polystyrene beads are trapping air in their internal cellular structure so maintaining a lower thermal conductivity than, for example, solid polystyrene spheres when acting as a conducting bridge. But I think it may be an open question as to whether 0.033 W/(mK) quoted for EPS accounts for airflow or not.

You're sounding like my millennial Son. Funny how us old fogies are more into the hi-tech scene 😁 I jest. It'a a valid view - unnecessary complexity is not a good thing. Anything critical to the smooth running of a household has to be self-contained in my opinion. As soon as you reach beyond your walls for services you're at the mercy of others so I'm quite envious of off-griders. The best I can afford to do is build my own smart services for lighting, heating, security etc. and not buy into the commercial offerings for these things. it's also the reason I prefer, if practical, to code a microcontroller in preference to using a SBC like the Pi for simple tasks as even maintaining a Pi has complexities whereas the code running on a microcontroller is ridiculously bulletproof. I think this is one small miracle that's often overlooked - I've still got PIC chips that are running code that I flashed into them in the early 90's reliably performing the same functions for over 30 years now. Even stupid mechanical things will fall over on these timescales.

Ha! It happened again just now. All my raspberry pi's were unreachable other than by ping and had stopped logging out to a remote database just like the last time - Saturday 6th Novemeber. Rebooted the router and about half an hour later it was all working fine again. Obviously doesn't like Saturday's.