Knowing when to replace your heating system isn't always obvious, but knowing what signs to look for can make it a little easier.

• A noisy heating system could be a sign that you have an undersized duct system or a serious operating issue. Either way, comfort doesn't come with loud noises.

• If your heating system is more than 10 years old, upgrading to a properly installed ENERGY STAR®-certified system can significantly improve your heating costs and your comfort.

• Multiple visits from a professional could be costing you a lot in repairs and on your energy bills.

• Uneven heating can be a sign of leaking ducts, uneven ductwork or system performance issues.

• Leaky ducts or poor equipment operation can lead to big problems. High humidity can lead to mold or other biological toxins. Excessive dust can stir up allergies all year round.

If you've noticed any of these signs, it might be time to consider replacing your heating system.