This is another extremely popular item with endless claims circulating on the internet regarding its insulating capabilites, durability and usefulness. It is one of AMK’s top selling products, claiming to be water and wind proof while reflecting 80% of the users body heat. We found the usual company jib here.
Unlike traditional bivys which serve to keep out the elements while offering little thermal protection, the S.O.L Thermal Bivvy has the added benifit of heat reflection. More on that below.
The Thermolite has a velcro closure system along the top few feet of the bag. This is convenient but the bag is not waterprrof because of it. In the rain you will have to keep this area out of contact with water if you want to stay dry. Is it windproof? Sure.
There is vent in the foot of the bivy for condensation prevention that is a welcome feature.
Is it durable? We actually think the bag is reasonably durable and easily more than a one time use product. This was one of our primary concerns with the bivy and we have to say we were impressed. It is not made of kevlar. Like much of your gear, if you jab it with a sharp stick it will get a hole in it.
We took ours to a 7 degree F walk-in freezer where we put it on our test subject along with shorts, shoes and a T-shirt. Even while our subject was standing up, the AMK Bivvy wasn’t up to the challenge and he had to leave the freezer after 7 minutes, the temperature in the bag having dropped below 50 degrees. Laying down on the cold floor would have been a complete disaster. We took it into a 34 degree F walk-in refrigerator where it held better but was ultimately inadequate there too. When the company says you can use it alone at temperatures greater than 50 degrees, we believe them.
Of note, when the Thermolite Bivvy was placed over our sleeping bag while in the 7 degree F freezer the temperature inside our bag improved by 7-10 degrees. Not bad. Other reviewers have found it very effective when used in this manner as well.
The extreme light weight, adequate quality and low cost when compared to other bivy systems make this a competitive choice for emergency preparedness kits and hiking or camping excursions. As above, the product had limited capacity to keep us warm in signifcantly cold conditions when used by itself, you should consider this carefully.