Yes, just a little while ago I said that convection is a term applied to moving liquid. Yet it’s also applied to air, at least by oven salesmen. Convection ovens are much like conventional ovens (they can be either gas or electric), except that they contain little fans. The fans circulate air around the interior of the oven, causing warm air molecules to bump into your food at a higher rate than they would if the air were inside were still. Of course there’s always at least a little convection going on in an oven, the fans just speed it up.
What effect does all this convection have on, say, a loaf of banana bread? More convection means more heat absorption, which means a shorter baking time (about 15%). Greater efficiency of heat transfer also means you can bake the same bread at a somewhat lower temperature (again about 15-20% lower). So what’s the big whoop? you say. I say the same thing myself. All that efficient heat transfer is cool on an intellectual level, but it really doesn’t save me much in utilities since the running fans take up energy of their own.
What I will say about a convection oven is that the moving air does eliminate the so-called “cold spots” in an oven, and that means foods bake up more evenly with less (if any) turning. But there again, I don’t much mind turning, since it gives me the opportunity to look at (and maybe poke) whatever it is that I’ve got going in there. Except when I’ve worked in a bakery, I’ve never baked in anything other than your run-of-the-mill cheapie GE or Whirlpool (though there was this one apartment I rented that had this half-mile wide, WWII-era, white enamel beauty in it…it couldn’t hold a temperature to save it’s life) and I’ve pulled splendid bakery out of all of ’em. Convection ovens do sound nice in principle, but in practice they’re really not necessary.