bathroom fan electrical system

When to Replace or Upgrade a Bathroom Fan

Is Your Bathroom Fan Working Properly?


The bathroom can be the most humid room in your home, and an updated bathroom fan can save you from headaches in the future. Because it’s the room where you and your family enjoy steamy showers, run cozy bubble baths and run the sinks for toothbrushing and face-washing, it’s easy to see why your bathroom would have the highest humidity level in your house.

If your bathroom is poorly ventilated, all this warm steam can cause excess moisture buildup. This extra moisture can cause:

  • Mold and mildew
  • Bad odours
  • Poor indoor air quality
  • Peeling paint or wallpaper
  • Lifting or splitting of laminated plywood vanities

In more extreme cases, this may cause structural damage by penetrating into your home’s drywall, attic insulation, and structural joists.

Besides removing odours, the main purpose of bathroom ventilation is to remove all that extra moisture from the bathroom before your furnishings and finishings suffer water damage.

But how do you know if your bathroom exhaust fan is really working properly?

When Does Your Bathroom Exhaust Fan Need Servicing?

One of the biggest mistakes is thinking that just because your bathroom fan is making noise, that must mean it’s working.

Is your bathroom exhaust fan actually pulling out humidity and moisture, or is it simply making noise?

If you’re finding excessive moisture on your mirrors and walls, this can be a major indicator that your bathroom ventilation isn’t working properly.

If your bathroom exhaust fan is making a lot of noise, is slow to start, or is failing to remove moisture, your bathroom fan needs to be cleaned or replaced.

It’s important to note that if your bathroom fan starts to smell like burnt plastic, this is a fire hazard. This means your fan is failing or there are problems with your electrical wires. This should be replaced immediately to avoid any bathroom fan fires.

The best way to tell if your bathroom fan is in need of servicing or replacement is the “toilet paper test”.

To do the toilet paper test:

  • Take 2 pieces of toilet paper
  • Turn on the fan and place the toilet paper against the fan cover
  • The fan should suck up the toilet paper and stay attached to the fan
  • If not, your bathroom exhaust fan isn’t working efficiently

Typically, your bathroom ventilation should be cleaned at least 1 or 2 times a year. If you keep up with routine cleaning and maintenance, your bathroom fan can last up to 10 years or more.

It’s possible to clean your bathroom fan yourself. But for a more thorough cleaning, it’s recommended that you hire professionals.

How to Clean Your Bathroom Fan

A quick inspection and cleaning may be the solution to the poor ventilation in your bathroom.

How to clean your bathroom exhaust fan:

  • Shut off your electrical circuit to your bathroom to avoid shock
  • Remove your bathroom fan cover
  • Use a damp cloth, or an upholstery brush or crevice tool on your vacuum
  • Remove any dust, cobwebs, and other debris from the fan and housing
  • Replace your bathroom fan cover
  • Turn your electrical circuit back on

While it is possible to remove the motor and clean it as well, it’s highly recommended that you leave that to the pros.

Once you have completed these cleaning steps, try the toilet paper test again. If it holds this time, your bathroom exhaust fan is working efficiently.

If not, it’s time to replace your bathroom ventilation.

What should you consider before upgrading?

Airflow Rates For Your Bathroom Exhaust Fan

Airflow rate is an important factor when considering a new bathroom fan.

Air movement is measured in cubic feet per minute (CFM). This is the standard measurement of fan airflow in a bathroom.

According to the Home Ventilating Institute, following proper guidelines will ensure efficient ventilation.

  • For bathrooms under 100 square feet, the basic rule is to exhaust at least one CFM (cubic foot per minute) for every square foot of the bathroom area.

For example, an 8’x10’ bathroom (80 square feet) would require a minimum of 80 CFM.

  • For bathrooms that are over 100 square feet, the calculations are based not on square footage, but on the number and type of fixtures in the bathroom.

Consider an allowance of 50 CFM for each standard toilet, bathtub, and shower.

More importantly, you should allow 100 CFM for whirlpools and hot tubs because these generate the highest levels of humidity.

Besides finding the right airflow for the right space, what else should you look for?

Finding the Right Noise Level

Sound levels in bathroom fans are rated in sones, not decibels. The sones rating is a measurement of how sound is perceived by the listener.

The lower the rating, the quieter your fan will be. If the bathroom fan doesn’t carry an HVI rating, chances are the fan will be noisy.

Typically, a good sone rating is 1.5 or lower. But it’s important to note that if the level of noise is too quiet, you may forget that it’s on!

Always look for that “Energy Star” rating to ensure energy savings and superior efficiency with far less noise.

Basically, two of the most important features of a bathroom exhaust fan are quietness and removing moisture and odours. Now that you have a good idea of what you need, you have some choices between models and innovative features for your new bathroom fan.

Features of Modern Bathroom Ventilation

Typically, bathroom fans vent out through a duct running up to the roof.

Choices of bathroom fans include:

  • Simple box fans that are installed in the ceiling
  • Combination bathroom fan/light fixtures
  • Combination bathroom fan/light/heater fixtures
  • Wall-mounted bathroom fans to avoid much ductwork

Bathroom exhaust fans come in a variety of selections, depending on your style and needs.

Additional features of modern bathroom exhaust fans include:

  • A timer switch
  • A nightlight
  • A humidity sensor
  • A motion sensor
  • Adjustable fan speeds
  • Bluetooth connectivity
  • A speaker to play music
  • Thermal heat protection

There are also fan/light fixtures available with decorative globes and finishes to suit any bathroom style.

Keep Your Bathroom Space Free From Moisture

Unless your bathroom fan motor stops working entirely, it can be difficult to know whether or not your fan is pulling moisture out of the bathroom.

If your mirror is steamed up after a shower, or if there’s a buildup of condensation on your bathroom walls and ceiling, it may be time to service or upgrade your bathroom ventilation.

Ideally, you should only have to run your bathroom fan for about 20 minutes after a shower. If you’re finding there’s still excessive moisture in your bathroom, it’s time to contact the professionals.

Kobalt Systems offers expert full-service electrical, communications, and security services. Founded in 2015, our professional team of highly-trained master journeyman electricians offers the most cost-effective solutions for your home or property. Contact us today about replacing your bathroom ventilation, and so much more.