following on from this https://singletrackworld.com/forum/topic/retrofitting-cavity-wall-insulation/

I had a chap round earlier to quote on insulating the wall. Its a single wall, approx 7m x 3m, no interruptions, good access (scaffolding up everywhere) and will be filled from the inside (so less messing around with making good)

the quote was £1500 which seems really high to me – I can’t imagine a load of insulating balls cost much more than £100, nor that it would take more than a couple of hours for one chap to do it. I accept I might end up paying a bit more per meter than a bigger job, but wondering if anyone had recently had cavity wall insulation put in and could provide a cost they paid. I don’t want to waste the time of more companies if this is the going rate..

I had a quote for my whole house about 18 months ago and was shocked at how high it was. Sorry can’t remember the exact amount.

Decided against it as payback was a long time as we don’t use the heating that much.

I paid £2025 for 150sqm with a 75mm cavity – the grey bonded poly beads type.  I’m in a bungalow but the gable ends are quite high and due to the lay out of the house I have three. I used arrow insulation who did a good job of the survey and insulation. They also came back very quickly to sort a minor issue (some beads spilled into the loft). I think they cover all of the south east.

This was 2022.

https://www.moneysavingexpert.com/utilities/free-cavity-loft-insulation/

Theres a section in here advising on whether cavity wall insulation will help you? I live near the top of a hill above Morcambe Bay, have been offered it for free, but reading this makes me think it’s not a good choice for me. I don’t have any damp issues, and I’d like it to stay that way

You could insulate externally and clad for that figure