Sparrowhawk

I grew up near a birds of prey centre and regularly visited so I have a soft spot for them, and have become accustomed to birds will do what they will do. I have much less sympathy with cats.

Thanks @SteamyTea! Is there a guide I've missed on this forum? I've seen old car radiator fans mentioned as suitable - are there any others? When I removed a 'strip of shame' (plastic gap-fillers between the wall and window frame) around the double glazing I discovered that not only was it open to the cavity behind them, but the double glazing hadn't been foamed into place with flexible foam/any foam at all. I can imagine there are hundreds of air leaks round there.

Thanks Marvin. I have learned an expensive lesson there. The noise reduction was maybe worth it (less sound of rain thundering on the Velux windows) but I won't be doing it again in a hurry. AIM and APE are great acronyms. AIM will be my goal, and I am celebrating the slight condensation we now get on windows as a sign that the airtightness is better than it was 2 years ago. As an aside on PV the roof isn't particularly suited, as it's hipped and the south facing aspect has a gable over the bay window which breaks it up and shades one side. I calculated 16 years for payback in September, which is longer than we plan to live here (esp if the house remains stubbornly cold!)

I plan to have the radiators replaced as we cannot bleed a few of them (either rusted shut or won't re-seal after bleeding), or they have no fins. I'd love to do a re-plumb however with engineered or laminate flooring in most rooms it would be an expensive exercise to lift and replace the flooring as well. I have got myself confused over flow temperatures and what to use. I've done the calculations for 3 rooms so far and assuming the worst-case of -2C outside and 20C (or even 18C) inside, I can't find radiators big enough for an average flow temp of 45C (boiler output 55/return 35). I guess that's what weather compensation is for so the boiler then runs at 70/50 on those unusually cold days. So which temperature should I use for radiator sizing so that for most of the year I can run on low(er) flow temperatures? As a check on my workings, for the lounge which currently has a 110x70cm double and a 155x55cm double radiator in the bay window, after entering the wall/window construction I have calculated Air Changes (assumed) 1.5 Room Temperature 21 °C Delta-T 24 Heat Loss Requirement 4114 W / 14047 BTU Floor Dimensions 6.2m × 3.9m (24.18m2) Height 2.55m At delta T of 50 it's just possible to get big enough radiators in the same places as the current ones to meet that heat loss requirement. A modern Stelrad double 110x70cm is 2212W and a 1400x450 is 1919W. I can increase the height of one (and maybe raise the bay window windowsill to do the other) but how do I account for lower boiler temperatures at other times?

That is my fear that it is uneconomical to do anything about it. We have a cavity (filled with electrical cables) and all air bricks vent the cavity so in effect we have single-block-width solid walls around our property. I'm currently doing one using Stelrad Stars which has many different types of wall construction programmed in but doesn't do well with half-conventional ceiling half-warm-roof rooms and other unusual construction. If there's better software I'm all ears and will pay for it, as Stars is a pain to use.

Not this time, it means I've put it off until I can line up all the bits (e.g. builder to sort the vents, and prob advise how to block the top of the cavity or do it for me, unless that's a job for the insulation installer; decide who to believe about cables). The cold spell has made it much more pressing. I've just grabbed the manual for the cooker out to check. It's a ceramic hob Rangemaster that should use max 32A but recommends a 45A breaker. So that could be 10kW. This second fuseboard/link would be the one an EV charger goes on in a few years, so that's what - another 7kW? So... maybe? Replacing with a bigger cable would be the easiest way. I get why the previous owners had it put in this way as they'd just had a new engineered wood floor laid in the room between the fuseboard and the new one and didn't want to take it up, but under the floor would have been more sensible and I'd reroute it this way if I could.

Thanks Mike that's awesome to hear. No heating engineer I've spoken with has said more than a handwavy "it should save you money" yet. Currently doing my radiator sizing calculations. delta-t 35 will not cut it for the coldest periods, but looks like it'll work nicely the rest of the time.

I contacted an EPS bead manufacturer to see what they would say. I'll paraphrase so as not to out them but their technical team was of the view that: "The plasticiser serves to make the cables flexible, but once they are installed they no longer need to be bent or moved. Even if the plasticiser leaches out and the cable becomes brittle it'll next be moved when being replaced, at which point if the outer insulation crack the it’s of no consequence." It's the opposite of everything I've read online, but it seems to makes sense. But I'd want an independent view before going ahead. What do people think? In my case I've also got other blockers to cavity wall insulation as blocking the top of our walls with rockwool looks to be impossible without removing the soffits none of our air bricks are sleeved the previous owner had an 80A cable installed up one cavity, across the loft (under the insulation 🙄) and down the other cavity to a fuse box in the extension and I'd not want that surrounded by insulation.

Yes, keen very amateur birdwatcher and enjoying the coastal waders and occasional marsh harrier down here. Are you? I have found Jeremy's threads invaluable, as well as people's assessments of products e.g. Sunamp when thinking "could that be better than replacing our tank like-for-like. It's also appears to be a less... intimidating forum than some of the others with better natured members and fewer spats and general aggro. We shall see if that holds true 😁 Great advice. I shall try and break down the "WTF do I do next?" into intellible bite-sized questions. Always the hardest part with a mind teeming with ideas and aware of the dependencies that "if I start to do this it'll impact this that and the other bit, which means I then need to do that as well and I think I'll have a nice sit down instead and pretend it's warm". I don't think I know what they sound like! We have a local pair and before we started taming the wilderness that was the garden the female used to bring pigeons and eat them under our bushes. On the second day of this cold spell the male snatched a bird off the bird feeder and I've spotted him hanging around on neighbours' roofs keeping an eye out for more snacks.

Hi everyone, 5+ year reader and finally taken the plunge to join. It's almost 3 years since we bought our house, a 1920's detached house extended twice (late 1990s/early 2000s, the latter extension considerably better quality than the first). I wanted to build a Passivhaus but the impossibility of finding a plot at a sensible price prevented that. We soon discovered this house was cold and draughty and we could see daylight in the eaves storage. Since then I've sealed all the obvious drafts, used a thermal camera to try and find others, had the 3 worst windows replaced with triple glazing (an expensive mistake: I thought it would fix these rooms as the windows weren't airtight but it didn't), but it's still a cold house. Living here during the cold spell that's just ending drove me to join this forum as I'm not sure what to do next. We need a new heating system (25yr old boiler, radiators of same age) which I'm expecting will make the house warmer but won't reduce our gas usage unless I can reduce heat loss. Looking forward to getting stuck in!

Same here. Prime candidate for cavity fill but they rewired by dropping everything via cavities, including an 80A cable to the 2nd fuseboard/electric cooker in the extension on the other side of the house. I have an email from a technical manager at an insulation company saying it's not a problem because the cables inside a wall don't move once it's filled with insulation, so if the sheath becomes brittle it doesn't matter... That's one I've joined this forum to discuss in more detail - once I land on the correct section to post on.