Certain telltale signs indicate it's time to consider replacing heating and cooling equipment, or improving the performance of your overall system. It may be time to call a professional contractor to help you make a change if:
Consider replacing with ENERGY STAR qualified equipment that uses 20 percent less energy than new standard models.
Consider replacing with an ENERGY STAR qualified furnace, which is 15% more efficient than a conventional furnace. If you have a boiler, consider replacing with an ENERGY STAR qualified boiler that is 10% more efficient than a new, standard model.
Your cooling or heating equipment may have become less efficient.
Improper equipment operation, duct problems or inadequate insulation could be the cause.
Install an ENERGY STAR qualified programmable thermostat or have a good contractor install one and instruct you on its use — to start saving energy and money while they're away or sleeping.
Poor equipment operation, inadequate equipment, and leaky ductwork can cause the air to be too dry in the winter or too humid in the summer.
Leaky ducts can pull particles and air from attics, crawl spaces and basements and distribute them throughout your house. Sealing your ducts may be a solution.
You could have an undersized duct system or a problem with the indoor coil of your cooling equipment.
Energy Star - U.S. Environmental Protection Agency - U.S. Department of Energy