My bathroom fan isn't removing moisture - what's wrong?

Your bathroom fan likely has reduced airflow due to a clogged exhaust vent, accumulated lint in the fan housing, or a failing motor. Most moisture removal issues stem from blocked airflow rather than fan failure.

Start by checking the exterior exhaust vent on your roof or wall. In Vancouver's wet climate, these vents often get clogged with leaves, bird nests, or debris, especially during our heavy fall and winter rains. Look for a flapper or louver that should open when the fan runs - if it's stuck closed or blocked, no air can escape. While you're outside, make sure the vent isn't damaged or has gaps where rain could enter.

Next, remove the fan grille inside your bathroom (usually held by spring clips) and clean out any dust and lint buildup. Vancouver homes tend to accumulate more moisture-related debris due to our high humidity levels. Check if the fan blades spin freely and listen for unusual noises when running. A motor that's struggling or making grinding sounds may need replacement.

Proper sizing matters significantly - your fan should move at least 1 CFM per square foot of bathroom space, or follow the Home Ventilation Institute's recommendation of 50 CFM for bathrooms up to 100 sq ft. Many Vancouver homes, especially older character houses and Vancouver Specials, have undersized fans that can't handle our climate's moisture loads.

This also includes ensuring your exhaust terminates outside - never into an attic or crawl space, which violates the BC Building Code and creates serious moisture problems in our wet climate. The ductwork should be insulated to prevent condensation, and use rigid or semi-rigid ducting rather than flexible dryer hose, which restricts airflow and sags over time.

If cleaning doesn't solve the problem, the motor may be failing. Bathroom fan motors typically last 8-12 years in Vancouver's humid conditions. Upgrading to a higher-quality fan with humidity sensors can automatically manage moisture levels - particularly valuable during our long rainy season from October through March.

When to call a professional: If the fan requires new electrical connections, ductwork modifications, or roof penetration repairs, hire a licensed electrician. Any electrical work must be done by a Technical Safety BC licensed contractor and inspected. For ductwork running through attics or complex routing, an HVAC contractor can ensure proper installation and code compliance.