3 Residential Exhaust Fans

Any exhaust fan within a home is designed to remove contaminated air. They are a usually a simple system and do not have the ability to replenish that air. The air removed needs to be replaced to prevent negative pressure within the space. In most cases, the air will balance from other locations throughout the home naturally. An open window or infiltration will do the job. In some cases, especially new homes, there must be a means for air to get back inside the home. A whisper grill is one way to alleviate this negative pressure. The whisper grill is a grill directly through an exterior wall which can be opened or closed as required. It will allow air to pass through passively when pressures vary. Whisper grills are also used for appliances like gas fireplaces to replace the air used through combustion.

Bathroom fans are an important unit within any home. With showers, a large amount of humidity is produced and a bathroom will quickly grow mold without a way to exhaust the moisture laden air. Bathroom fans can work off a simple switch or humidistat. They will create a negative pressure within the space, but they are usually not strong enough to effect a home. If you ever want to check your bathroom fan for effectiveness, turn on the fan and close any windows and the door. Then take a piece of bathroom paper and slide it close to the bottom of the door where there is a gap. The negative pressure will pull the paper through the gap and right up the inside of the door. If it does not work, you fan is not strong enough or not operating properly. Bathroom fans must be vented directly to the outdoors.

Kitchen exhaust fans remove the air which contains any food odors, moisture and/or grease. They will cause the same negative pressure as a bathroom fan, but because they are in larger spaces it is usually unnoticeable. Kitchen exhaust must be vented directly to the outdoors.

Dryer vents are the one item that must never have screws in the ducting. The duct must remain smooth as possible to avoid bits of lint being caught inside. A small piece of lint will eventually develop and become a blockage in the pipe causing a fire hazard. It is very important that only tape and straps be used to hold dryer vent together. A dryer vent must be vented directly to the outdoors.