Venting a Basement Bathroom Fan

Adding a bathroom in your basement has many advantages. If you are turning your basement into additional living quarters, a basement bathroom will complete it. It eliminates the need to go upstairs to use the bathroom. If you just want to cut down on waiting time for access to the upstairs bathroom, the addition of a basement bathroom will definitely help.

Regardless of the purpose, any bathroom needs ventilation. This is important for health and hygiene as well as the prevention of mold and mildew growth. Venting a basement bathroom fan can be somewhat tricky. This article will help you do so properly.

Most basement bathrooms don’t have windows. A basement can be a dark and dreary environment. The ventilation of a basement bathroom is second in importance only to adequate lighting.

To make the bathroom more pleasant it needs a fan to circulate air and remove odors and moisture. Exhaust fans can be quite noisy. You will need to weigh the power of the fan against the noise factor and choose one that best suits your basement bathroom needs.

The CFM or cubic feet per minute is the amount of air a fan can move in one minute. This is the rating you use to make sure that the fan is strong enough for your bathroom. The easiest way to determine the CFM required for a bathroom is to allow for one CFM per square foot of room.

Once you have determined the size of the fan you must then read the manufacturer’s instructions for the duct work. You must also factor in the length and width of the duct work into the CFM rating.

Placement of the Fan

The fan should be placed at the highest level in the bathroom. Moisture, hot air and odor all raise to the top. Many people make the mistake of mounting the fan directly in the center of the bathroom. The fan should be placed over the toilet or shower/tub area. Above whatever area or appliance that creates the most moisture is the best spot for placement of the fan.

Position the fan so that it is parallel to the joist bay. You can insulate the ductwork to prevent condensation. The duct should be run between the joists. Make sure that the size of the duct will fit. Using a smaller duct than recommended will result in poor performance.

Plan where the ductwork will terminate. Follow the vent to where it meets the outside wall. The fan must be vented to the outside. It should be vented away from any fresh air intakes. Consider the outside placement as well. Look for a spot that is out of the way and out of sight.

Mark the place where the duct terminates by drilling a small hole through the exterior of your house. To prevent damaging the siding cut a hole the same diameter as the vent through it from the outside.

Continue by cutting a hole the same size directly inside the opening in the siding. Be very careful not to cut into any wires. It may be necessary to hold them away from the vent opening prior to cutting the hole. Screw in the vent cover and seal the perimeter with foam insulation.

Another issue you may have to deal with is the presence of existing ductwork, pipes and poles. You will have to plan around them. Adding odd or too many angles to a bathroom fan vent can prevent the fan from properly functioning. If you must run extra ductwork to accommodate these obstacles make sure you factor this in choosing the fan’s CFM capacity.

Types of Fans

There are different types of fans. They are available with combinations of fan, light and heater. A fan/light combination is perfect for limited ceiling space, as is usually the case with basement bathrooms.

Building a quality basement bathroom will increase the value of your home. Proper ventilation is very important because it will reduce the amount of moisture that will lead to mold and mildew and eventually rotting and decay. If in doubt about your ability to install a bathroom fan in your basement consult with a professional or better yet hire a contractor.