Exposing the insides – how our online U-value calculator works

calculator xray

Previously we’ve talked about what a U-value is, what the targets are for U-Values and what else you get with your calculation if you use our U-value calculator. Today we will explore how our online-value calculator works.


To give you an idea of the scale of our U-value calculator there are over 6,000 different U-values held within the database supporting it. Each calculation has a range of questions, and options for each question, and we have added in caveats and tool tips, as well as images of the insulation and details of the construction build up. But you will only ever see the questions and options for the particular type of application you are interested in, meaning that you should never have to answer more than eight questions to get a U-value.

Look up tables vs calculator

We built the Kingspan U-value calculator to act as a look up table. This is a type of calculator, but it doesn’t carry out any calculations as you put your figures in, instead as you select options and answer questions it filters through the database of pre-calculated U-values until there is only one left which matches your requirements.

When you have got this you can bookmark the page to save your calculation or get a PDF emailed to save for your records. Or if you are not happy with the U-value you can change the insulation thickness, or go back to an earlier option and change your answer, working through the calculator again until you are happy.

We’ve set up this way for a number of reasons:

  • Pre calculated

The U-Value that is provided to you has been calculated out by a BBA approved competent person. This means that the calculation will be been worked out by a person who has been trained and certified to carry out the calculations, and who is audited on a regular basis. In this way you can be assured that the number provided is accurate and that the correct values and methods have been used to calculate it, taking into account common assumptions and construction methods.

  • Common build ups

The build-ups in the calculator are all common construction build ups and, as far as possible, we have specified the most commonly available materials, and thicknesses of material. For example plasterboard is assumed throughout to be 12.5 mm thick with a 3 mm skim coat on it. Where we have made assumptions on thickness or density of materials in the build-up these are noted, either in the caveats or in the build-up details for that application.

We’ve provided dropdowns for thicknesses of insulation – this means that you can only get U-values for sensible thicknesses of insulation and build ups that are commonly used. It means that you can be sure that the U-value you end up with is for a construction that can actually be built and for a thickness of insulation that can actually be manufactured (always check with us about what is in stock though). We don’t let you guess how the wall, floor or roof might be constructed.

  • Appropriate/relevant questions

As you work your way through the calculator you will find more questions appearing. This is because we only asked questions appropriate for that application, for example if you are getting a calculation for a wall, then you will only be asked questions for a wall – structured in a way so that they lead on from each other. You are only asked the minimum number of questions in order to get to the U-value you need. We only show thicknesses of build-up elements that are commonly used in that situation – so you don’t have to look up all the details to get your u-value – they are built into the calculator. By the end of it you should have a shopping list of products that will allow you to get the U-value you have selected.

  • Helps avoid mistakes.

We wanted to make life as easy as possible for the you when you are using our u-value calculator as we know how frustrating it can be to have to work out the thickness of every element in your build up. We’ve avoided that by letting you pick the type of application and then we add in the all the common details, so you only have to select the information required to get a U-value.

There are two other things that we wanted to highlight about our online u-value calculator:

  • Free to play

You don’t have to sign up or register to get a U-Value from our calculator. You can go straight on it and start playing with different applications, and different build ups in those applications. It means you can try out as many different combinations for the application until you are happy with it, then if you want a permanent copy emailed to you we will just need your email address. We do ask for a few project details which are then used to personalised your calculation when we email it to you.

  • Call us

In some situations on the U-Value calculator we’ve asked you to call us. This is because we really need to talk to you and understand your project before we can give you a U-Value – this would be allow us to assess what the best solution will be and what thickness of insulation will achieve this.

For example if using Optim-R, a vacuum insulation panel, which gives a much lower U-value to an equivalent thickness of board, then this insulation would be provided with an enhanced specification designed for the particular application.

Obviously this is a bit more involved process and we would want to make sure that the information that we give you is accurate and specific to your project. In order to make sure that we do this then you will need to contact us to go through the project in detail. So don’t be surprised if you get to a particular application and we ask you to call us. It just means that we want to make sure you get the right information.

We hope that this has given you a bit more insight into how our U-Value calculator works – have a play with it at www.uvalue-calculator.co.uk and let us know what you think, either in the comments below or by through email at info@kingspaninsulation.co.uk.

To find out more about the u-value calculator and how it works check out the rest of the posts in this series which are linked below.

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Kingspan Insulation is a market leading manufacturer of optimum, premium and high performance rigid insulation products and insulated systems for building fabric and building services applications.

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