What could cause my interior air handler to become noisy? The home is about 12 years old. i went away for the weekend and return to a noisy air handler. It's a Lennox, sounds like it's coming from the blower. What should i do?

could be the blower motor, or the blower wheel. Alos there is a cance something got sucked up into the wheel. Turn the power of and spin it by hand see if it rubs or makes a vibration.

Other things to check are loose mounting screws, or the blower wheel might just need cleaning.