So let me explain my conditions first. I have a medium sized box a few feet high (enough to grow) and everything I need but the problem is it gets really hot in the box if I use a high watt bulb. I've tried cutting holes in it and everything but it really doesn't do much but the light I use now is bright but not insanely bright. And I have aluminum lining the inside. I have other bulbs I could put in the lamp but I think it'd be to high of a wattage (is that possible lol) but is it bad that the lighting isnt that good? It still grows but I'm not sure how big it'll get...
need to get a fan in there and hook up some computer fans in the to actually suck the air out. they sell some at radio shack for cheap Cooling systems - Components & parts - RadioShack.com
Make sure your air intake is at the bottom and the air-out is at the top! good look man hope everything works out for ya!!
mylar to cover a small cupboard grow would be less than 10 dollars. but i agree white paint will do just fine as well