What is your feeling about staple up vs gypcrete with cost versus efficiency? Anna http://www.green-talk.com

Unfortunately, the simple answer to your question of cost is that it depends on whether or not you need to do anything with your existing floor. For example, if you have carpet that you intend to tear out and replace with tile, that makes the gypcrete option significantly more affordable, though it still may not be as (installation) cost-competitive as staple-up. If you’re happy with your flooring the way it is, staple-up is likely the way to go.

As to performance, that depends on the use of the area. The less thermal mass you’re heating, the more “responsive” the system; that is to say, it reaches the desired temperature more quickly. For example, if you like to sleep in a very cool room, but want a little heat to help you rise in the morning, a bedroom floor that heats relatively quickly might serve you better than a floor that takes an hour to warm but can hold heat for much of the day. That said, continuously occupied spaces are most efficiently heated with more thermal mass (a thin slab, like gypcrete, or a deeper slab).