mattress moisture barrier

Optimistic Paranoid wrote:
There are three methods of heat transfer. Convection, conduction, and radiation. Reflectix has NO insulation value as far a convection or conduction goes. It reflects radiation - AND IT NEEDS AN AIR GAP in order to do THAT.

My My. This reminds me of the blind men feeling an elephant. All are correct, as far as they know.

The above is mostly true. Reflectix has a marginal R value of 1.1 for conduction.

The original question was about moisture in the mattress. Moisture is generated by the body and will migrate down through the mattress material (except some foam mattresses, toppers and air mattresses). If the mattress is cold, the moisture will condense where the dewpoint temperature is encountered. Condensed moisture in or under the mattress will promote mold growth.

One solution presented here is to ventilate the underside of the mattress to allow air flow. This air gap stops conduction, can help remove moisture and insulates slightly.

Another solution is to use a foam topper to prevent migration of moisture down through the mattress. Some of us sweat when sleeping directly on a foam topper because moisture cannot penetrate.

A third solution here is to insulate under the mattress to keep the mattress above the dewpoint temperature. The moisture will migrate out after you get out of bed (assuming it is not too humid in your TC). A sheet of foam is probably best for this solution.

Another solution is to use a heating pad to elevate the temperature of the mattress above the dewpoint temperature.

All solutions work in some situations, but not all work for all situations.

Putting reflectix under a mattress provides marginal insulation, but in some cases, might be enough. Unless one reflective surface "sees" air, it will not function as a radiant barrier, only as a marginal conductive barrier. The air inside the mattress does not count.

Hope this helps,

(I needed a break from writing Christmas cards ;))