Sea to Summit Ultralight Insulated Mat

I purchased the Sea to Summit ultralight mat to replace an older, uncomfortable, poorly insulating mat I owned.  I was drawn to this mat because of its supremely lightweight and small pack size.  Weight is everything on the trail. 

The small and light Ultralight mat in its package

The Key Features[1]:

  • Regular: 480g (On my kitchen scale it weighed 483g including the repair kit)
  • Packed Size: Ø10 x 23cm
  • Unpacked Size: Regular size 183 x 55 x 5cm
  • Fabric: Ripstop Nylon (40D)
  • Insulation: Thermolight
  • R value: 3.1
The mat on my kitchen scales weighs in at 483. Did Sea to Summit measure without the repair kit?

A quick point about the R-Value.  The R-value is a measure used to rate how well a sleeping mat prevents heat loss. Thermal resistance is a measurement that indicates a materials ability to insulate.  There are several different ways to define this, but the starting point is the R-value.

A 3 Season Mat should have an R-value between 2.0 to 4.5.  Mats with between these R-values are suitable for typical temperature ranges of +10C to -10C[2].

I am amazed by how light, small, and fast to inflate this mat is.  The stuff sack is used to inflate the bag.  There is an attachment at the end of the sack to the mat.  Air is then blown into the stuff sack before filling the mat.  I did initially think “this is another thing to break” but it does in fact prevent the build-up of humid air and microbes inside the mat.   In addition, it is easier and quicker to blow up the stuff sack than a small valve.  I think it takes me on average, 2.5/3 full stuff sacks to fill the entire mat and this can be done in minutes.

Unpacked mat
The stuff sack used to inflate the mat
The stuff sack connected to the 1 way valve to inflate the mat.
The inflated mat. It took me 9 lungful’s of air to fully inflate

I was dubious of the build quality and suspected it might puncture when on hard ground.  However, so far, after many nights sleeping outside in the mountains in the UK and abroad, I have nothing but praise for this excellent sleeping mat. 

The Sea to Summit design has air sprung cells which help keep your body off the ground while keeping your body warmer.  I sleep on my side, and I can actually sleep in relative comfort on this mat.  If I said I never walk up I would be lying but I only move maybe once or twice rather than the 30 – 40 time on the old mat.

The mat uses all sorts of thermal technology which aims to keep you warm.  I would love to explain how these work but I am not knowledgeable enough in these area.  I can confirm that as a regular user of the mat, it is comfortable, hardwearing and has kept me warmer than previous mats. 

Pros:

  • Comfortable even for a side sleeper
  • Tiny pack size and weight
  • Easy and fast to inflate
  • Lifetime Guarantee

Cons:

  • Cost – at £120 it is on the higher side than other mats
  • It is noisy.  Moving around on the mat sounds like I am sleeping on a crisp packet!
Photo taken with my GoPro during a night bivvy in the alps. I used this Sea to Summit mat for the night, wonderful!

[1] https://www.cotswoldoutdoor.com/p/sea-to-summit-ultralight-insulated-sleeping-mat-D2424172.html

[2] https://ultralightoutdoorgear.co.uk/r-value-explained-i206

Total Page Visits: 139 - Today Page Visits: 1