After 18 years, I have to replace my JennAir double wall oven. The top oven is convection/self-cleaning and the bottom is just standard. They're 27" and my main complaint is that I can really only cook one thing at a time in each oven. If I try to put two pans of anything in a single oven, there just isn't enough room for the heat to circulate. I'm wondering if this is a function of a poorly designed oven (I despise mine, btw) or if convection is necessary for using multiple racks in a smaller capacity oven. I'd rather avoid the extra cost of convection, but if it will help make the best use the oven space, I'll consider it.