Free U-value calculators

[edit] Introduction

U-values (sometimes referred to as heat transfer coefficients or thermal transmittances) are a measure of how effective the elements of a building's fabric are as insulators. That is, the degree to which they prevent heat from transmitting between the inside and the outside of a building. The lower the U-value of an element of a building's fabric, the more slowly heat is able to transmit through it, and so the better it performs as an insulator.

It is important to understand the physics, mathematics, practicality and impact of U-values before moving onto the calculation of U-values. However there are an increasing number of software packages that include U-value calculations within them along with other functions and many simple online U-value calculators.

There is an article on Designing Buildings about U-values and a page called Thermal bridging in buildings both of which will give some background to the subject along with a number of other related articles on Designing Buildings.

It is important to understand that U-value calculations can vary dramatically as a result of the way the are calculated and the factors that are considered it is therefore important to understand concepts in order to assess the accuracy of any calculators that are used.

Whilst Designing Buildings does not endorse any of the following and suggests the users seek professional help or guidance if they are unclear on any detailed points, below is a list of free or minimally priced U-value calculators. They are divided into sections as these may influence some of the factors that are considered.

[edit] U-value calculators developed by consultants

• https://www.elmhurstenergy.co.uk/u-value-calculator/
• https://www.ikonografik.co.uk/free-area-weighted-u-value-calculator/
• https://jpatechnical.com/products/
• https://www.ths-concepts.co.uk/how-to-calculate-u-values/

[edit] U-value calculators developed by other organisations

• https://www.ubakus.de/u-wert-rechner/?
• https://greenbuildingcalculator.uk
• http://www.energiberakning.se/U_value/U_value.aspx
• https://www.changeplan.co.uk/u_value_calculator.php
• https://www.yourspreadsheets.co.uk/u-value-calculator-to-bs-en-iso-6946.html

[edit] U-value calculators developed by product manufacturers

• https://insulation-uk.com/technical-services/tools/online-u-value-calculator
• https://bim.rockwool.co.uk/u_value/
• https://uvaluecalculator.ecotherm.co.uk/calculator/
• https://www.knaufinsulation.co.uk/uvalue-calculator
• http://bguvalue.techlit.co.uk
• https://k.systems/ewi-tools/u-value-calculator/
• https://u-valuecalculator.com/gb/
• https://www.superglassuvalue.co.uk/calculator
• https://www.swisspacer.com/en/caluwin

[edit] Related articles on Designing Buildings

• Conventions for calculating linear thermal transmittance and temperature factors.
• Conventions for U-value calculations (BR443 2e 2019).
• Emissivity.
• g-value.
• k-value.
• Heat loss.
• Heat transfer.
• Insulation.
• Limiting fabric parameters.
• R-value.
• Standard Assessment Procedure SAP.
• Thermal admittance.
• Thermal bridge.
• Thermal resistance.
• U-value conventions in practice: Worked examples using BR 443.
• U-What?
• What do design professionals need to know about U-value calculation conventions?

[edit] External references

• Planning Portal: Approved Document L (Conservation of fuel and power).
• National Calculation Methodology website.
• Standard Assessment Procedure.

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