could be the bearings going out. call a service man.

My old furnace made the same squeal. You're about to throw a belt on the blower motor.

The rattling is probably poorly fitting furnace panels or ducts from the install.

Marco

No blower motor = no heat.

Heavy rattle can also be bad rubber insulating bushings.. It can mean an unbalanced blower wheel.. It is not right if it rattles. If you place your hand on any of the ducts, and the noise stops, you have found the loose component. Most blowers are not belt driven. A loose belt will squeel, but a direct drive blower probably needs the bearings lubed.

If you have a power vented furnace, the mounts may need adjusting or motor is just noisy. I dont know what brand you have, but Carrier will warranty noisy combustion motors.

Still laughing, mr.hvac. We don't have a kitty or a piggy, but it sure sounds like one got his tail caught under the rocking chair. The squealing sound is becoming more constant now, but DH is ignoring it. Maybe he believes in the power of prayer more than the furnace repair guy. It's cold and snowy in Indy and I hope the furnace doesn't die on us. If it does die, I'll have another opportunity to say "I told you so"! DH justs loves that phrase. Oh, the furnace is a Bryant which is about 4 years old. It has always rattled. Looks funny also since the Bryant face plate is upside down. We've always wondered about that.