Do you think your sleeping bag is not doing the job it was described to do?
Not keeping you warm enough?
You are not alone. Mine failed me.
It’s a common problem, because whilst your sleeping bag might say “rated to –3 degrees”, chances are if the weather

When I was in –4 degree weather, my –8 degree sleeping bag failed me. I had been pretty confident that I would be OK in these cold temps, even a little cocky!! It turned out to be a long night.
On return home, I went looking for something to help me and restore my confidence that I could sleep in the colder weather.
We invested in a Sea to Summit Thermolite Reactor Liner.
We have the Extreme, which is meant to, and I stress meant to, increase sleeping bag performance by up to 25°F (14°C).
I think that’s a big call….NO WAY does it add that much to a sleeping bag! I would say maybe 4°C?? Yes, I was a little warmer in it (and I am a cold sleeper), but not as warm as I hoped for.
But if you want
- a liner (keeps your sleeping bag clean)
- some extra warmth
- use it as a sleeping bag itself in summer
Have you used this product? Did it work for you? Add a comment.