Online Insulation U-value Calculator

The Celotex insulation U-value Calculator gives you instant access to calculating your required insulation thickness and product solution.

U-value Calculator
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IMPORTANT: On 1 September 2017, Celotex took the precautionary measure to temporarily suspend the supply of Celotex FR5000, Celotex CG5000, Celotex CF5000 and Celotex SL5000 while we investigate the results of recent tests (Parts 6 and 7 of British Standard 476). Materials relating to these products are for information only.
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This professional Celotex U-value calculator is one of the most comprehensive online calculation services in the industry, with a variety of different insulation applications covered.

Specify your desired U-value before immediately calculating the required insulation thickness and product

"I use the members area of the Celotex website on a daily basis. In particular I use the U-value calculator within the member area because I can quickly produce U-value calculations for inclusion within my projects' specifications" - Robin Bradbury of Bradbury Design

"Thank you for the online U-value calculator, it is really easy to use. I plan to specify Celotex from now on. It's more commonly available and easier all-round" - Jon Gay, architect fom Lochaber

In order to access the Celotex U-value calculator and download your calculation pdfs, you must register for the members area, which is quick and easy!

How to access and use the Celotex U-value calculator

The following video explains how to access and step through using the online U-value calculator. 


Register now to use the Calculator Calculator Icon

Why register?

Our U-value calculator app is also available from the App Store.

If you require further help or advice on an already created U-value calculation and would like to speak with an advisor, please contact our Celotex Technical Centre on 01473 820850.

Lines are open Monday – Friday, from 8.00am – 5.15pm.

Please note, some products in the U-value calculator may not be available from stock and subject to minimum order quantities and extended lead times.