Reflectix Material for Ground Cloth

do a search of reflectix … a cheap foam pad will provide more insulation for ground use

not to say reflectix wont work … just that for ground use there are better solutions

relectix has a ground R value of 0.67-1.1 depending on who you believe … blue foamies from 1.3-1.4, and zlites/ridgerest considerably more

For Reflectix (or any radiant barrier) to work properly the reflective surface must have an air gap against it. If I understand your proposed system correctly, both reflective layers will be in intimate contact with either your ground sheet or your pad.

Reflectix, as I understand it, is bubble wrap with an aluminized layer on each side. The air gap is provided by the bubbles; it's between the reflective layers (which I'm pretty sure are reflective on both the inside and outside). I've successfully used regular bubble wrap as a sit pad without any popping but I've never tried sleeping on it.

I wasn't sure if both the inward facing and outward facing sides of the top and bottom were aluminum or not. The bubbles would indeed provide the air gap thus rendering the radiant barrier effective.

I've got some in front of me, the insides of the coating are indeed reflective. I'm not sure that this would work though because both sides are reflective, so it seems that the heat reflected back up would immediately be reflected back down again….like light caught between two mirrors it might just bounce back and forth. It seems ideally you'd want just one reflective layer on the inside to reflect heat back up…..just a few musing by a non-engineer.

I did consider since both sides are reflective, if this would null the warming effect. Since I use the Big Agnes Air Pad, I have read that the air that is trapped in the pad itself can become cold, and actually make me colder. It maybe a waste of time to bring an extra "Reflectix Pad", and then have it reflect the cold air up due to the BA. I am new at Tarp Tenting in cold, so looking for a better than average ground strategy.

Thanks for all the feedback, much appreciated.

Again not an engineer, but there's probably a reason they've manufactured the product with the reflective layer on both sides. Presumably the radiant barriers would reflect the heat back and fourth ad infinitum as neither a net loss or net gain. You'll primarily have heat transfer through conduction. Being that the reflectix is a closed cell type material, convection heat transfer would be significantly reduced. Overall, I would imagine that the thermal performance of a reflectix pad would be more beneficial than a closed cell pad of similar thickness.

Scott,
I'm assuming that the reference you made to the BA Air Pad and that the air could become cold is mostly found in their Clearview pad. Without any insulation or radiant barrier, the cold ground would easily transfer into the pad cooling the air. With the air as the only method of insulating you from the ground, that would be a unpleasant experience.

A while ago, I posted an inquiry about whether using material from one of the state of the art space blankets, with ample perforations, would be worth the weight to improve insulation in a sleeping bag or quilt.

The response, from some of the engineers who visit this site, was a unanimous negative.

Have lost count since of the number of threads on the same subject.

This kind of product development, and discussion about it goes many years back to the "Texolite" sandwich that was incorporated in sleeping bags and found to be of marginal value by BP magazine (That was the 'old' Backpacker).

Until someone comes up with some hard evidence that there is a reflective barrier or coating that provides more warmth for weight than good quality insulation, or vapor barrier if you are into that; then, where are we going with this?
Sam

I have had good results over the years in cold weather of using E blankets to line my tent and then place my gear on top. I even line up the walls a bit. What it does is block the wind and the loss of heat. I can sit on the floor directly on top of snow or frozen ground with no issues.

It does though crinkle badly and you run the risk of condensation (you have to be careful!).

I still haven't gotten around to it but I had considered using Insul Bright, the material I use in our FBC Cozies, to make a tent liner. It is mylar that is coated with fabric – breathable and not crinkly. It is also thin and readily packable. You might consider it as a liner.