Thoughts for ground cover option? Double bubble reflective foil insulation?

Welcome, Ken.

I’ve used Reflectix a number of times.  I live in Alaska, work as an engineer, and need the air and water lines in my systems to operate year-round.  I’ve also used it to move frozen foods (usually sockeye salmon and halibut but sometimes caribou) across state lines at 33,000 feet.  I’ve got a bit of it in my own house (which I built) where I wanted more insulation in a tight space.

It’s highest use would be when you’ve got minimal volume, no compression load, and a high temperature differential (that’s when the IR reflection helps the most, well, works at all – when you have a delta T across an air gap. The extreme example is the vacuum gap in a Thermos bottle which is why the inner surfaces are silvered).

If I was going to crash somewhere in a bush plane, I’d rather have a roll of it along, then not.

But in lieu of groundcloth and foam pad?  Cheap.  Waterproof.  But not nearly the R-value of closed-closed foam (CCF) or a self-inflating foam pad nor the toughness of tyvek nor the extreme lightness of polypro.  If I was relying on it under my body, I’d throw in some CCF pads for under my hips and shoulders where my weight most compresses the insulation under me.

I think it would be more successful over your body but under your quilt, as you suggest, to allow for a thinner quilt 0 use a 40F quilt at 25-30F comfortably.  It wouldn’t quite have that lovely, light-as-a-cloud feeling of a 850- or 900-FP down quilt, because it’s a bit stiff but it wouldn’t weigh much and I suspect it would add 10-15F of comfort.  I wouldn’t plan on using it every night, but if I was cutting it close on my bag/quilt, it would be really nice on the coldest few nights.

But I’ve never tried as part of a sleep system.  It’s the kind of thing that would great to try out in your backyard before trusting on it on the trail.

Thank you for your quick reply and wonderful insights David! Seems your are the perfect
person with scientific and years of hands on experience with this.

Yeah, I’ll just get a small pack and try it in the backyard and see. It’s probably not the holy grail I thought it was but a fun experiment for $14.

Cheers, and I’d happily volunteer as air drop target, on your next crossing state lines with those tasty frozen foods.

I, too, live in Alaska and I have a friend who used to use Reflectix as a sleeping pad on hunting trips here on Kodiak in September – November, sleeping in a silnylon pyramid with a TiGoat wood stove and no floor.  I tried it myself, but the lack of cushioning was uncomfortable for me.  In recent years, my friend has gone to the Thermarest Z Lite Sol sleeping pad as have I although recently I prefer my Xtherm.  Both are more bulky and heavier, but far warmer and comfortable than Reflectix.  I have also used it for insulating my frozen fish & venison when flying down to Arizona, but that baggage was transported in an unheated baggage compartment anyway.

As far as the coldest camping I’ve done which was several Denali expeditions and some other Alaskan trips, we all paired a closed cell foam pad with a full-length Thermarest. – this worked well in snow caves as well as tents.

I do carry a square of Reflectix in my day pack as a seating pad.

Thanks Michael.