You've decided to cut energy costs in the kitchen by upgrading your appliances. A friend suggested converting to a gas cooktop and it sounded like a good idea -- except as you recall mom always talked about how dirty gas was. Not the case. Gas seemed dirty in the old days because range hoods and exhaust fans were neither readily available nor properly engineered. Fortunately, that's no longer the case. Yes, gas gets hot faster and is a more cost-efficient source of heat -- but remember -- when converting from an electric cooktop to gas, make sure to upgrade the range hood as well. Look for a hood that exhausts the number of cubic feet of air per minute recommended by the cooktop maker. And that's the On The House tip for today.