Against a background of rising energy costs, manufacturers have made great strides toward improving window efficiency. The advantage is that, in homes with high-efficiency windows, the HVAC system need not work overtime to counteract the effect of drafts and air leaks. The homeowner therefore enjoys lower monthly bills. Indeed, for the budget-conscious, windows are no longer a liability. If you're looking to cut costs, Dave Lincon of Sears Home Services recommends concentrating on windows rated by Energy Star. After all, he says, there's a simple reason why the Sears Weatherbeater line carries the certification: "At the end of the day, Energy Star windows help you save."