Looking at the AMK website I see two different AMK Heatsheets. One is larger and is for two people, I guess, although it says its only 20% larger. Is there any other differences between them? Also, I can;t find out how small they pack. Anyone know?

20% larger than competitors.

Haven't seen the small one, but the two-person version packs smaller than a video cassette. Fits in your back pocket like nobody's business.

Thanks for the clarification. That makes more sense.

The smaller one is just like the regular silver space blanket - about the size of a cigarette pack. The larger 2 person one, is a bit larger then the 1 person one. I would say its about 3x5x1 inches when folded.

I believe the emergency bivy they sell (the smaller package of the two bivy bags on their site) is made of the heatsheet material.

What is surprising is that, the way their advertising reads anyways, the smaller packaged bivy seems to be higher rated for keeping you warm. That seems counter-intuitive to me. Even if it isn't as I perceive it to be, I still prefer the smaller packaged bag for packing convenience. I bought some last Xmas as stocking stuffers for the girls, and as more gear for me.

Those yellow whistles look a lot like the Fox Micro 40 ones I own.

I have yet to try out the heatsheet material in cold climate. I would like to see how effective the thinner bag really is.

I thought the same thing until I used one of the Heatsheets blankets in the Sierras. I ended up making a bivvy of sorts by taping the edges of it with duct tape. It keeps more of the heat inside. (Of course it keeps more moisture too, but at least I was somewhat warm)

they are



What I ended up using was a combination of a Thermo Lite and a Heatsheets. I climbed inside a Thermo Lite and then wrapped Heatsheets blanket (now a bivvy) over it. Temperatures at night dropped to about 40. I was wearing socks, pants, t-shirt, light fleece and rain shell, while sleeping inside a tent. I was relatively warm, but would get chilled if there was even the slightest wind.

Overall, I would recommend this, or similar set up, only when temperature stays above 50. Anything below makes things uncomfortable. (Then again, I do tend to get cold rather easily )

Well, comfort aside, I reckon the idea with these things is to keep you alive more than anything else. I guess long as it keeps you dry in a rainstorm and keeps the wind off your back, you got a better chance than without it. If the reflective heat claim is at all realistic, that'd be an improvement over garbage bags enough to warrant the added cost I suppose.

I haven't done a lot of testing with the Heatsheets and Thermolite bivvies, but my understanding is that the Heatsheets has better reflectivity because of the material. However, there is no way for moisture to escape, so you get condensation on the inside.
The Thermolite has a vent down by your feet to prevent this. The material is more durable, making it last longer in a survival situation or even reusable as a lightweight bag when doing ultralight backpacking in warmer weather.

Either is greatly augmented by some fill material (fleece sleeping bag, fleece jacket, blankets, etc).

Ew-w-w-w-w. Maybe they should put the vent somewhere else to protect the innocent.

Last winter I used the bivy as an inexpensive vapor barrier liner to my down bag. The bivy worked ok, but I did tear a small hole in it and you'll never get packed down as small once you open it up. For my next winter trip I'm going to buy a real vbl for my bag and I'll put the AMK product (with hole duct taped) in my emerengy gear stash.