Sea to Summit Reactor Extreme Thermolite Liner
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- 110g/m2 Thermolite construction throughout
- Adds up 25F (14C) to warmth to a sleeping bag
- Mummy shape with a box foot. Draw cord hood with mini cord lock
- Packs into its own Ultra-Sil stuff sack
- Color of liner is orange. Weighs 14 oz / 399g. Dimensions: 84 / 210cm x 36 / 90cm
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Increases sleeping bag performance by up to 25°F (14°C) with super-insulating 110g/m² Thermolite fabric. Thermolite is a hollow core fiber that provides extraordinary warmth for its weight and remains extremely breathable. Spacious design allows for a comfortable night’s sleep, even when the mercury plummets. Perfect for extending the season of your sleeping bag.
Color: Red | Size: One Size
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Temp: 30° F Precipitation: 60% Wind: 0-5 mph Conditions: Cloudy with light sleet
• Sea to Summit Thermolite Reactor - Extreme
• Marmot Trestles 30 Sleeping Bag
• Alps Ultra-Light Air Pad
• Eno hammock
• REI Medium weight base layer
Test conditions: All temperatures taken from three locations (center of chest, center of body and center of left thigh) using an infrared thermometer and then averaged. When I added the liner, I got out of the sleeping bag and allowed 10 minutes for it and the pad to cool.
Ground Temperature at start of test 28° F
Temperatures at 5 minutes w/o liner
• Outside of sleeping bag w/o liner 42° F
• Inside of sleeping bag w/o liner 66° F
• Base layer w/o liner 75° F
Temperature at 15 minutes w/o liner
• Outside of sleeping bag w/o liner 45° F
• Inside of sleeping bag w/o liner 69° F
• Base layer w/o liner 77° F
*Added Thermolite Reactor
Temperature at 5 minutes w/ liner
• Outside of sleeping bag w/ liner 43° F
• Inside of sleeping bag w/ liner 64° F
• Sleeping bag liner 68° F
• Base layer w/ liner 82° F
Temperature at 15 minutes w/ liner
• Outside of sleeping bag w/ liner 44° F
• Inside of sleeping bag w/ liner 74° F
• Sleeping bag liner 80° F
• Base layer w/ liner 86° F
As you can see from the numbers, the sleeping bag and pad was working at their designed levels and keeping me comfortable with a base layer temperature of 75-77° F with an outside temp of 28-30° F. When I added the liner, I went from being comfortable to being very warm as my base layer temperature went up to 82-86° F with the outside temp still at 28-30° F.
Now, about the +25° F claim. I have no way of knowing what a 7-9° F increase inside the bag equates to in temperature range outside the bag but, I can say this. For the size and weight, I would recommend it as a comfort item, if you can fit it into your budget.
While this test/review isn’t comprehensive, I did apply somewhat of a scientific approach and tried to give you something better that “this is great” or “this sucks”.
I not carry this as my "improvised sleeping bag" for summer and spring camping.
Before using the item: Very cold, unable to sleep
After applying the item: Nice and toasty.
My sleeping bag is two-stage, meaning it is essentially two sleeping bags one inside the other. I have applied this liner to the outside of the inner sleeping back, so inside the outer bag. It seemed to definitely improve the temperature by at least 10 degrees.
At 5am in the middle of the woods I didn't bother bringing a thermometer to check the actual temperature, but it was enough of a difference to change miserable night experience into comfortable sleep.
I do have the next step down in this liner, but was afraid it would not have been enough. I am very satisfied for the extra warmth.
I stayed warm! It was great! I’m guessing temps dipped into the 40”s . So base layer, thermal socks, liner bag and insulated mat under my cot and I was ok. I do wish there was a side opening but maybe that would affect the warmth. I’ve never used a bag liner before. Soft and cozy.
My favorite sleeping bag is a 40 degree down bag from Kelty that I can use pretty much year-round with this liner. It adds the little bit of extra warmth you'd want in the early spring and late fall, and if it's hot enough in the summer you can just leave the bag at home and use this instead.