You expect to encounter snow in Scotland in March so I wanted to be sure that whatever mat I took would provide excellent insulation. Thermarest launched a new version of the All Season mat for 2017 which has their new Speed Valve hence the SV. This clever innovation allows the user to blow up the mat much faster and more easily than a conventional valve. We had seen it demonstrated but were curious as to how it would perform in the real world. I asked if we could test one and Thermarest kindly sent a mat to test.
We found that when you blow into the large open neck on the mat, some clever physics results in your breath drawing additional air into the mat. The Speed Valve adds a little bit of extra weight over the previous All Season mat but it really does work! Each night I blew up the mat with no red faced exertions. It’s much quicker to blow up than the conventional valve and the mat still has a normal valve to top the mat up and to make adjusting the pressure easy. Once inflated you roll down the neck of the mat like you would on a dry bag to seal it closed.
I woke up after the first night on a decidedly soft mat and was worried that perhaps this means of sealing the mat wasn’t as effective as it should be. I counted the number of rolls I’d put into the neck and found that I was one short of the number stated in the instructions. User error then! On subsequent nights with the correct number of rolls the mat performed faultlessly so it is important to follow the instructions (something that so many of us don’t do). One benefit of the SV valve is when it comes to deflate the mat and pack it away. Undo the neck and the air rushes out of the large opening allowing you to roll the mat up without the need to keep squeezing air out of the valve.
The All Seasons SV was a dream to sleep on and you can actually feel your body heat being reflected back by the mat as it insulates so effectively. We didn’t encounter any snow but one night there was a heavy frost and another was in a damp and cold bothy and the All Season SV helped contribute to a comfortable night’s sleep. The internal structure of the mat means that you can lie on the very edge and it never feels like you are going to fall off or the mat flip over. I’m a side sleeper and appreciated this quality of the mat and its rectangular shape allowing more room for my legs. Pack size and weight are reasonable given the size of the mat and it’s very high levels of insulation.I wouldn’t hesitate to recommend the Thermarest All Season SV to anyone requiring a mat that truly can be used in all weather conditions.