Install Bathroom Exhaust Fans to Remove Moisture

Before power ventilation was invented, bathroom ventilation was performed by simply opening a window. As we have progressed in our understanding of energy efficiency, indoor air quality, and moisture control, bathroom ventilation fans have become the main tool used in order to evacuate moisture from the bathroom and prevent mold and mildew from forming.

Different Types of Bathroom Exhaust Fans

As with all bath fixtures and furnishings, from plumbing and skylights to sunken tubs and marble tile, a homeowner, architect, or interior decorator can spend buckets of money in this space. Understandably too, because there is such a high return on investment with bathroom remodeling projects.

Almost all home builders install inexpensive contractor-grade fans, even in high-end houses. But there are options. Many units incorporate a light fixture. This is a handy option because there is only one electrical switch to flip when entering the room.

An additional option is a heater. The further north the home is located, the more of a viable option this becomes.

Upgrade to Peace and Quiet

The next thing to think about is the noise factor. Basic units simply have the fan motor sitting mere inches from the grill. They simply vent the air into the attic. This in itself is not a problem if the attic is well-vented with ridge vents, solar powered vents, or whirlybirds.

But the noise can be irritating, especially for exhausted people who relax with candles, a tub of hot water, and a glass of wine. There is a solution. There are models on the market that actually have the motor 8 to 10 feet (2.4 to 3.0 meters) up into the attic space.

There is a flexible duct secured to the top of the fan. The attic ductwork exits through the roof or the side of the home and the motor is connected right into the duct. It’s amazing how quiet these fans are.

Installing an Exhaust Fan

If there is an existing fan, the job is fairly straightforward. Buy a unit that’s the same size or larger to make sure that it will cover properly. One thing to pay attention to is the wiring. A unit that incorporates a heater may need a dedicated circuit for the heating element.

Most modern fan housings screw directly to a ceiling joist so it may be necessary to remove an existing electrical box.

Some fans are powered by two-wire cable and some by three. Check for this and make the appropriate changes. Remember:

  • Whenever working with electrical connections, turn off the power at the circuit breaker box.
  • Always check the local electrical building code and comply with it.

When making an installation in a bath not equipped with an existing ventilation unit, it will be necessary to cut the hole in the ceiling, run the cable and install any ducts and vents to the exterior of the home.

Why is Water Coming Out of My Bathroom Exhaust Fan?

One common complaint of homeowners is that during the cold winter months, the fan will drip water, causing damage to the drywall. This is caused by a few different reasons, all of which have simple solutions.

Turns in the Ventilation Pipe

It is common knowledge that the most twists and bends you have in an air duct, the harder it is to push air through it. Many times, ventilation pipe is improperly run in a twisted mess that does not allow the power of the fan to pull air through it. The warm, moist air collects in the pipe and forms condensation which flows back toward to bathroom and drips out the fan. This can typically be solved by cutting the ventilation pipe and making it shorter so that the pipe has a smooth curve to it all the way to the vent where it exits the house.

The Pipe is Not Insulated

Often times the main reason a pipe will collect condensation is because the warm moist air inside the pipe makes the exterior of the vent pipe warm, causing it to form condensation when the cold attic air hits it. Installing an insulated duct line that is completely insulated from the bathroom ventilation fan to the exterior vent prevents the cold air from reacting with the warm surface of the duct because the duct is protected by the insulation wrap. This type of pipe should be attached with zip ties and taped at all seams with duct tape.

The Ventilation Pipe is Too Long

Ventilation pipes that are attached to bathroom fans should not be more than 12 feet long for proper air movement. Most bathroom fans are rated for 60 CFM which barely meet the requirement of what is needed to evacuate moisture from a bathroom. If the pipe is too long, a negative pressure is created in the pipe which causes the air to basically be pushed back in the pipe before it can reach the exterior vent. This sucks air from the exterior down the pipe and forms condensation when the warm and cold air meets. Shortening the pipe will take care of this issue.

Bathroom ventilation may seem like a simple concept, but it seems that this is something that professionals make mistakes on all the time and often can be easily prevented or repaired with a few simple changes.