My bathroom exhaust fan is loud and rattles.

A loud, rattling bathroom fan is usually caused by one of three things, most of which you can fix yourself. Before you decide to replace the entire unit, try these steps:

1. Clean the fan (The most common fix) Dust buildup on the fan blades or the housing can cause the fan to become unbalanced, leading to vibration and noise.

• Turn off the power to the fan at the circuit breaker.
• Remove the cover (usually held on by spring clips).
• Vacuum the inside and wipe the blades with a damp cloth. If the blades are plastic, you can often pop the fan assembly out to clean it more thoroughly.

2. Tighten loose components Vibration often comes from parts that have shaken loose over time.

• Check the screws holding the fan housing to the ceiling joist.
• Check the screws holding the motor assembly to the housing.
• Make sure the fan cover itself is snapped firmly into place.

3. Check for obstructions Sometimes debris, like a piece of insulation or a small pest, gets into the housing or the ductwork. While the cover is off, use a flashlight to check for any items that might be hitting the fan blades as they spin.

When to replace it: If the fan is clean, tight, and free of debris, but still makes a high-pitched grinding or "growling" noise, the motor bearings have likely failed. Because replacement motors can be expensive and difficult to match to older housings, it is often more cost-effective and easier to replace the entire unit.

If you are comfortable with basic electrical work—turning off power, using a wire stripper, and using wire nuts—this is a manageable DIY project. If you feel unsure about the wiring, it is best to consult a professional.