OK, I made the trip to Home Depot today, light meter in hand ... in a nutshell, the shiny white 'pebble-grained' fiberglass shower-enclosure-type paneling' was a BAD reflector of light (15 foot-candles on my meter)... very disappointing, but, it was too expensive for me anyway $$$$ ... same for some white 'plastic' panels they carry, poor reflective qualities (15-18 footcandles) ... their 'flat-white Melamine-surfaced particle board' was MUCH better (25 footcandles) ... it reflects the same as flat-white paint, (which is pretty good, overall) ... it is available on 4'x8' sheets from 1/8" thickness to at least 3/4" ... that's probably what I'll use for my new cabinet ... I'm using Mylar now, and while it reflects the best when NEW, after a couple cleanings, it fogs, scratches, etc... I think I'll buy the Melamine-surfaced sheets, as they should be easy to clean, and durable, cleaning-wise ... this experiment wasn't very technical, I just measured the light falling on each board from Home Depot's overhead lights, but it seems to indicate comparative reflectiveness just fine ... I didn't find any of the 'bubble-sandwich insulation' ... :smokin: