Convection ovens have a large fan in the back and it circulates hot air in the oven to keep a more even temp throughout the oven (they are also called forced-convection ovens). They are supposed to cook food faster and cook more even than regular ovens. You can get convetion ovens as a single unit with the stove part on top (what we had in VA) or you can get them built into the wall as a single or double unit. You can get them in any form that you get a regular oven. Reg. ovens have a fan too, but you can't miss the fan in the back of a convection oven....and if I remember right, its more loud than a reg. oven. Also, our old convection oven let you cook either with the convection fan or without it and use the oven like a reg. oven. Not sure if they all do that.
I would think double ovens can only help the resale. If you have someone like me who comes in, I'd be all over the double ovens...drooling.
