I know this is kind of old topic, however it gave me a good place to start with bulbs testing with candlewarmers.com's cermic warmers. Been using and selling warmers for years but this brand is new to me, I was concerned what would happen if customers bought other bulbs besides a 25 W Halogen from candlewarmer. Because you know it will happen. Here are my results (of course these are with my tarts) so others may vary. Using a square warmer, with the 25 W from candlewarmer I had a very small amount of hang up on one side that wouldn't completely melt. I might add that these bulbs can be found a Hobby Lobby. I also tried the 35W short ones, The wattage is higher but the lighter area is smaller. They come 3 in a package from home depot for around $9. They gave me the same results as the 25 W. After examing closer I noticed the bulb socket in the warmers are not centered, hence the hang up on one side possibly! Lastly I tried a 35W Halogen from Menards, Home Depot have these too. Same size as 25 W but 10 watts more. This has done perfectly for me. I have been testing for 3 days with no problems yet. Full melt! I am going to continue with this one here at home for me, just so I know it is doable! If it does not work out I will let you all know. Hope this info will help some not have to drive all over town looking for bulbs to test! LOL