Preview
The snippet
Paste this where the box should go. The script lets the frame grow and shrink with its content; without it, the box still works at a fixed height.
Frequently asked questions
Is it free to put on my website?
Yes. Copy the snippet into any page. There is no account, no key and no fee, and the box carries a small “by U-Monkey” credit and a link back to the full calculator.
What does the box calculate?
A U-value to BS EN ISO 6946 with BR 443 conventions — the same engine as U-Monkey — for walls, pitched roofs at rafter or ceiling level, flat roofs and floors over outside air, using generic material values. It checks the result against the Part L (or Section 6, or Technical Booklet F) figures for new build or an extension in England, Wales, Scotland or Northern Ireland.
Can my visitors use real products?
The box uses generic λ values to stay small. The button under the result opens the same build-up in the full U-Monkey, where any of 400+ real UK products can be swapped in, the condensation check runs and the free PDF is one click away.
Does it track my visitors?
The box sets no cookies. It counts how often it is opened and which site it is on (the host name only), with Umami, a cookieless analytics service.