Cost-benefit/u-value difference calculator

[eandg]

I'm adding insulation to a SIPs kit. Had previously planned on adding 60mm everywhere but now considering going to 100mm in the roof. Cost difference approximately £700. Kingspan used to have SIPs as an option on its online u-value calculator but this has now disappeared. Is there an alternative calculator available and/or one which estimates the cost-benefit of doing so?

[SteamyTea]

Should be easy enough to calculate it from first principles.

As long as you know all the material's properties, and their surface area ratios, and the angle of the roof, should be easy enough to calculate.

Edited December 12, 2022 by SteamyTea

[Bonner]

... or try this simulator if you don’t want to do sums https://www.ubakus.com/en/r-value-calculator/

[eandg]

4 hours ago, Bonner said:

... or try this simulator if you don’t want to do sums https://www.ubakus.com/en/r-value-calculator/

Thanks - what I was looking for and can only just about work it out so would have struggled to do it myself!