# Why have my heat losses changed since the last time I opened the project?

To ensure accuracy, we regularly update our heat loss calculations in line with the latest regulatory guidance and to fix minor software bugs.

Read our recent [news and updates](https://help.heatpunk.co.uk/books/news-and-updates "news and updates") to stay up to date with changes.

<p class="callout info">Autumn 2026: we are updating the default temperatures of heated and unheated spaces in line with new guidance. These updates will automatically be applied to heat loss calculations on new projects. On pre-existing projects, you will have the option to **accept** the new heat loss calculations, or to view the existing project as it was without making any further changes to the floor plan. </p>

[![image.png](https://help.heatpunk.co.uk/uploads/images/gallery/2026-11/scaled-1680-/K0DO6dFG3cVBhehK-image.png)](https://help.heatpunk.co.uk/uploads/images/gallery/2026-11/K0DO6dFG3cVBhehK-image.png)