Self-inflating mat
A self-inflating mat is a sleeping mat with an open foam core that draws in air when its valve is opened, so it fills itself. You can top it up with a few breaths to firm it up. Its insulation is rated by R-value, and that matters as much as the bag above it.
Where you'll see it
It is sold in camping shops and on product pages, usually with a thickness and an R-value. The R-value is the figure to compare between mats. Check the maker's page for it, because a thick mat with a low R-value can still let the cold ground through.
What to check
- The R-value on the label or the maker's page, which shows how well the mat insulates.
- The thickness and packed size, since a thicker mat often packs larger.
- The valve and the maker's advice on storage, so the foam core stays in good order.
- Whether the mat's R-value suits the forecast low for your site.
Related terms
- R-value: the rating that shows how well a mat insulates.
- Sleeping bag liner: a thin layer that adds warmth inside the bag.
- Comfort rating: the bag figure to read alongside the mat's R-value.
Read more: sleeping mat R-values explained and, if one fits, the sleeping mat R-value guide.