Technical web application for UK’s leading radiator manufacturer

Case Study: Stelrad STARS Advanced Heatloss Calculator

We developed a web-based product specification tool for Stelrad, helping them to improve engagement and raise product awareness with their increasingly loyal customer base.

Technical online heatloss calculator web application

Stelrad’s STARS Advanced Heat Loss Program has been popular with customers for many years, providing a powerful tool for calculating heat loss in rooms and buildings. Aimed at radiator installers, contractors and specifiers, the original STARS program simplified the repetitive and complex calculation process and suggested appropriate products from Stelrad’s radiator ranges based on the results.

However, as a CD-ROM based Windows-only application, STARS was costly to distribute and maintain, with no means of directly engaging with its users. Our solution was to redevelop STARS as an online, server-based web application that could be accessed using a conventional web browser.

The browser-based version of STARS was a hit with both Stelrad and their customers. Customers loved the step-by-step workflow and intuitive drag and drop room planner for quickly specifying room layouts and building materials. Stelrad saw engagement go through the roof with the number of user registrations quickly reaching the thousands. And running the application centrally from a server means that updates to Stelrad’s product range can be rolled out in realtime.

In 2017 the user interface and was completely overhauled and support for smaller screens and mobile devices was improved. At the same time we developed a basic version of the heat loss calculator intended for domestic and trade customers with less detailed requirements. This too has proved to be very popular.

We recently integrated the STARS user registration process with Stelrad’s CRM system and the Mailchimp email marketing platform. This has provided Stelrad’s marketing team more direct access to the growing STARS user base introducing further efficiencies and time savings.


STARS has become the best recognised and most used heat loss calculator and radiator sizing software in the UK heating sector. We have more than 20,000 registered users of the software and it’s one of the best ‘added value’ tools we can offer installers up and down the country to ensure that the radiators they select and install provide the warmth and comfort everyone expects from radiators in their homes.

Chris Harvey from Stelrad project leader for STARS application development

Chris Harvey

Head Of Marketing · Stelrad Radiator Group