Does the membrane have any insulating value?
The air gap membrane has an RSI value of about R2. A point of note is that dry air feels warmer. This question often arises when discussing the installation of the membrane sub-floor. In this instance the answer remains the same but additional information becomes helpful. The human body does not measure temperature in degrees but rather by noting heat loss from the body. This is why a piece of wood feels warmer than a piece concrete even when both are at room temperature. The thermal conductivity of the concrete is higher which draws heat from your body quicker. Taking this into account, a finished basement with properly insullated walls will feel warmer with an Air-Gap Membrane sub-floor than without.
