If you've tried all of the energy-saving recommendations above but still find your house too cold and inefficient, then maybe—just maybe—it's time to consider replacing your furnace. The average life span for a gas—or oil-fired unit is between 15 and 20 years. Along with fridges and dishwashers, Energy Star also certifies furnaces from companies such as Bryant, Carrier, and York, among many others. Most are at least 15 percent more efficient than standard models and can save you up to 20 percent on heating costs.
Not sure if it's worth the money? Add up your fuel bills for last winter, then multiply that sum by 20 percent. Divide the result into the cost of buying and installing the new system, about $3,000 or so, and you'll see how many years it will take to recoup your investment.
Get three factors to weigh when deciding if it is time to replace the furnace.