The convection fan heats up real fast on this unit so you may want to adjust your cooking time just to be sure. But it's something that really surprised me because the wall oven I got takes some time to preheat
 this cosmo wall oven is surely one of the best ovens out there on the market because it performs like an expensive one but the price was really the factor for me which made me decide to buy it. 9/10 for me.