Have an exhaust fan question?
If you're looking to replace an exhaust fan, an HVAC company should be your first call. When choosing an exhaust fan, there are several different options: a fan only, a fan with a light, a fan with a heater or a fan with a light and heater. There are varieties in shapes and colors as well. Then you can choose whether to mount your fan on the ceiling or to the wall. It's likely those decisions were easy for you, one more to take into consideration is the noise level, called sones.
The sone is the unit used to measure perceived sound. A calm, quiet room is somewhere between .15 to .5 sones. A normal conversation takes place between 1 and 4 sones. So, the quieter fans will have lower sone ratings. If you’re looking to put a fan in a restaurant kitchen or construction workers bathroom, the sound level may not make a difference but you may want to look into the CFM number, I’ll explain that a little later. But if you want to put a fan in a bathroom near a nursery, the sound level may be of the utmost importance. Everyone has their preference for ideal fan noise. Just remember lower sone number = quieter sound.
For those that need fans to move air around, you’ll be focused on the CFM number. CFM stands for cubic feet per minute, meaning the amount of air the fan moves around every 60 seconds. You may have to do a small amount of math here to find your ideal number. Find the volume (length x width x height) of the area the fan will be placed in, for example if our bathroom is 12 feet long, 10 feet wide and 10 feet tall it has a volume of 1200 cubic feet. Divide the volume by 7.5; that equation provides the CFM number we’re looking for. Our bathroom requires a CFM of 160 (1200/7.5).
Fan only options and fans with lights need not be on their own dedicated circuit. Fans with heaters take more electricity than fans without heaters and need to have a dedicated circuit (its own line of power) to handle the extra power load. Whether installing a new fan or replacing an old fan with a heater a new line will need to be run from a breaker panel (one usually found inside the garage or utility room). When asking for a quote or scheduling an appointment you’ll need to have an idea of how far it is from the breaker panel to where the fan will be placed.
When to call HVAC
If you’re looking to place a fan where one is not currently, you’ll want to have an HVAC technician vent the area before an electrician comes in. Keep in mind, if there is no attic access and you’d like to add a switch to your fan, there may sheetrock damage to put in the wiring for the switch. The fewer surprises there are in your installation the better. If you're looking to replace an exhaust fan an HVAC company can also handle this type of call.
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