Adding Insulation to a crosswall house

RN7

Not sure why but thank link doesn't seem to work. 

Could be wrong but I thought EWI was a term usually used for building something additional on the outside of the existing wall and adding insulation that way. 

Rather than adding / changing insulation into an existing stud wall. 

plumb1_2

FreeBear said:

RN7 said:

FreeBear said:

jonnydeppiwish! said:

I’ve just finished some work with BC and they wanted rock wool, not celotex in the external wall. Not sure if this is a shift away from celotex?

Cork would be a viable alternative to Celotex or fibreglass/rockwool - Fire resistant, similar thermal performance to fibreglass, and doesn't have the problem with slumping. Would be a bit more expensive, and there are not that many suppliers in the UK.

I'd worry about pay back time in that case.

Going by some estimates of EWI (https://www.checkatrade.com/blog/cost-guides/external-wall-insulation-cost/), even at the lower end of £8K, it is going to take a very long time to get a return on investment. I'll have spent close to £10K on doors, windows, and insulation by the time I've finished the thermal upgrades here. Whilst I'm already seeing some savings, I won't recover the total cost in my lifetime. However, quality of life has been vastly improved by way of killing cold draughts and the place being easier to heat to a comfortable termperature - What price can be put on that.

Guessing about £10k

FreeBear

RN7 said:

Not sure why but thank link doesn't seem to work. 

Could be wrong but I thought EWI was a term usually used for building something additional on the outside of the existing wall and adding insulation that way. 

Rather than adding / changing insulation into an existing stud wall. 

Fixed the link.

If you were to insulate a whole house internally, I'd still expect a bill in the region of £8K unless you do the work yourself.

https://energysavingtrust.org.uk/advice/solid-wall-insulation/ claim a potential saving of £540 per year for a typical semi, so a ~15 year RoI.