There are several different types of bathroom exhaust fans. Most are rectangular and white or off-white, but there are some decorative fans available. Other variations include the level of noise produced, or sone rating, amount of air flow, and aesthetic design. There are also several types of add-ons that are often available with bathroom exhaust fans.
A quiet fan is generally the most desirable. Manufacturers rate the quietness of a fan with a unit of measurement called a sone. The higher the sone rating, the louder the fan. It is common for quieter fans to be more expensive than louder fans, though a fan with a rating between 0.5 to 1.2 sone will probably be fairly quiet without being too expensive. A fan which has a 2.0 to a 4.0 sone rating is usually too loud for home use.
Properly functioning bathroom exhaust fans normally produce approximately 1 cubic foot (about .03 m3) per minute (CFM) of airflow per square foot of bathroom. For instance, if the bathroom is 5 feet (1.52 meters) by 8 feet (2.43 meters), or 40 ft2 (3.71 m2), the bathroom exhaust fan should be at least 40 CFM. A large bathroom, which contains a whirlpool tub in addition to a shower, may require two small fans at opposite ends of the room to ensure that moisture will be removed from the bathroom efficiently.
Add-ons for bathroom exhaust fans include lights, night lights, and heat lamps. If the bathroom exhaust fan is the primary light source for a bathroom, then it is important to choose a fan with high enough wattage to provide plenty of light. A fan which only supports a low wattage light, such as 40 to 60 watts, may be too dim for a bathroom which does not have additional light fixtures. Night lights have a very low wattage, starting at 4 watts. Heats lamps have wattage ratings, ranging from 100 to 250 watts, for a heat lamp, to 1500 or more watts for an integrated heater.
The most common style for a bathroom exhaust fan is a rectangular shape fitted with a grill. A light is normally integrated into the middle of the grill. Slightly less common but still widely available, are round exhaust fans. Both the round and the rectangular forms are usually white or off-white to blend with to the ceiling color. Some exhaust fans are designed to be decorative and aesthetically pleasing. The grill of a decorative exhaust fan is camouflaged to look like a flush-mount ceiling fixture and comes in a variety of colors and finishes.
