For bathrooms up to 100 square feet in area, HVI recommends that an exhaust fan provide 1 CFM per square foot (approximately eight
Choose Ventilation Fans With Enough Capacity
To rid the average-size bathroom of excess moisture, make sure you have one CFM of fan capacity per square foot of space. Bathrooms over 100 square feet in size need an additional 50 CFM for each toilet, bathtub or shower, and an extra 100 CFM for a jetted bathtub.
Choose a fan that can ventilate at least 1 CFM per square foot of room. So, for an 80 square foot bathroom, select an 80 CFM fan. For bathrooms 50 square feet and smaller, it's recommended you purchase a bath fan designed for small rooms. In other words, choose under 79 CFM bath fans.
Ensure that all windows, skylights and duct connections are properly sealed to prevent leaks, which can introduce unwanted moisture into your bathroom. In areas with high humidity levels, consider using a portable dehumidifier in your bathroom. This can help reduce overall humidity and support your ventilation system.
When drain lines aren't properly vented, low pressure inside the pipe can suck water out of the traps, letting sewer gas in. Air pressure imbalances inside the drain pipe can restrict water flow and cause sluggish draining, often mimicking a partial clog inside the pipe.
Yes, the toilet and sink can share the same vent, as can the shower. It's common to have one main vent pipe for multiple fixtures, although you might need a larger pipe. You should check with local building and plumbing codes to confirm you'll have adequate piping for your home.
To fulfill the local exhaust airflow requirements of ASHRAE 62.2 (2010) and the International Residential Code (IRC 2021, Section M1507), bathroom fans should have a mechanical exhaust capacity of ≥ 50 cfm for intermittent operation or ≥ 20 cfm of ventilation when operated continuously.
If your bathroom does not have a ventilation fan, combating mould calls for a window that provides effective airflow. If you notice water beads on the walls after a shower, that's a telltale sign you have a problem. The solution is a bathroom window replacement that allows adequate fresh air to enter the space.
It's not uncommon especially for older homes to lack the necessary ventilation that modern-day bathrooms need. There are some simple solutions, like installing a window-mounted fan or a ceiling vent.
The most common configuration is to feed 2" PVC down from the ceiling within the wall behind the toilet. The vent pipe connects into the toilet drain pipe. The sink drain pipe and the tub/shower drain pipe are vented with 1.5" pipe that branches off from the 2" PVC mainline.
While building codes vary by location, most communities and states require an established form of bathroom ventilation. Exhaust fans are required in bathrooms that don't have a window or if the window is smaller than 3 square feet. The window must also open.
Keep the doors open. Keeping the bathroom door open after using the bathroom is a great way to help ventilate the bathroom if there aren't any windows. This lets out any steam that has built up when you were taking a shower or a bath.
One Foot In, One Foot Out – Ideally, you should place a bathroom fan in the ceiling about 1 foot from the shower and between the shower and the door.
Ventilation rates based upon eight air changes per hour are generally suggested. For most bathrooms this works out to one CFM per square foot of bathroom area. For example, a 7' x 10' bathroom would require a 70 CFM fan. A 50 CFM rating is recommended as a minimum for bathrooms 50 sq.
The duct should vent to the outside.
In general, the vent should be as close as possible to the fixtures it serves. This proximity helps ensure the vent can effectively equalize air pressure and prevent sewer gas entry. However, there are some common guidelines to consider: The vent should be within 5 to 6 feet of the fixture drain it serves.
Keeping your shower doors closed at all hours of the day locks in moist air and can lead to mold. After you shower, the interior space is at its wettest point. Try to keep the doors open for a half hour or so until the steam clears. If you have a fan in your bathroom, make sure to turn it on and let the air circulate.
A fan that is too big can cause a bathroom to be cold and noisy. This is why calculating the correct CFM is important.
If you have the fan on, and your door is closed, your bathroom fan will have to fight to pull fresh air through the tiny cracks. As a result, your fan will be less effective. Your bathroom should at least have a 12mm gap between the finished bathroom floor and the door.