Insulating above a Drop ceiling . Question.

[IlBeBauck]

Im going to have about 2' in the center above the drop ceiling, and of course a decreasing height as you move toward the exterior walls. Which is more effective ?: Insulate all the way up, or, leave an air space of some amount ? If the latter, how much air space ? (Id like to use Batt insulation). Thanks, David.

[trader4]

Not sure what you mean by "of course". Most drop ceilings don't have a decreasing height from center to the walls.

From an energy perspective, insulation is more effective than unconstrained free air. Impossible to say anymore without knowing what you have above the insulation.

[IlBeBauck]

1. If youre putting in a drop ceiling with a cathedral ceiling above it... the height between the drop ceiling and cathedral ceiling will vary as you move further away from center. This is my case.
2. What i have above the batt insulation going in, is a cathedral ceiling and beyond that id guess a few inches of roof insulation then the wood deck then the asphalt tiles. I suspected insulating all the way up was better than any air space. Thanks.