on top of the cage where to domes go there are big cut outs i got some foil and made a big square and cut out circules for the light to go through and the humidity came up a little more. but i would have to say that MDF i used for my other cage really holds in heat and humidity im thinking of saleing my cagesbydesign cage and build my boa a new bigger cage. Hes comeing close to 6feet now and i got him less than a year ago and he was 18" long