Ask Angi: What do I need to know about bathroom exhaust fans?

The bathroom exhaust fan might be the least glamorous item in your home. It’s small, it’s noisy and most days you probably flip it on without a second thought. But this modest little device plays a bigger role than you might expect, and it deserves a bit of care to keep doing its job well.

A bathroom fan does more than clear out unwanted smells. Its real value is moisture control. After a hot bath or shower, humidity lingers in the air, settling onto walls, ceilings and fixtures. Over time, that moisture leads to mold, mildew, peeling paint, damaged drywall, and even warped trim. A good exhaust fan pulls that damp air out quickly, helping your bathroom stay clean, healthy and protected.

Ventilation is key here. A fan must vent outside the home to do its job. If yours vents into an attic, crawlspace or ridge vent, the moisture doesn’t magically disappear. Rather, it just collects where you can’t see it, creating a perfect environment for hidden mold growth. Installers have several ways to route the airflow outdoors, including wall-mounted vents that push air directly outside or ceiling-mounted fans that tie into ducts or vent through the roof. Ceiling mounts offer the most efficient airflow since warm, humid air naturally rises.

If you’re considering adding a new fan, you have options. Handymen, electricians, and HVAC pros routinely handle this work. A typical installation takes three to four hours and costs between $100 and $900. Expect higher costs for first-floor bathrooms in multi-story homes because the installer may need to run longer duct lines. Silent or ultra-quiet models can also increase the price; some run around $200 just for the unit.

Some states require a licensed electrician to tie the fan into existing...