Backdraft Damper- The Key to Air Quality and Cleaner Air
As with any indoor vent, there is going to be what is called a back draft. Essentially a backdraft is the air trying to come inside through the vent where air is supposed to be going out. This will happen while an exhaust fan is not in use, so there needs to be a way to keep that air from getting inside.
An example of where this may occur would be with your bathroom fan or a kitchen exhaust fan. You don't want the hot outside air to come inside while you are not using them, so we use what is called a backdraft damper to prevent the air from flowing the wrong way.
Essentially a backdraft damper is a stainless steel vent that ranges from 4 to 16 inches, depending on the particular duct work, with "butterfly wings" on the inside, often made from aluminum. These wings will "flap" open in the direction the air is meant to go, while creating a seal when air is coming in the wrong direction. There is usually some sort of rubber seal to further help the prevention of leakage.
Rectangular backdraft dampers can be found on exterior walls to help relieve pressure from a particular side of a building as for use in a passive air system. Aside from that, you may also find them in an attic to help force out hot air, as well as in a furnace, chimney or other vents.
One example is a cape backdraft damper. Essentially, this is a valve that goes one way, which helps to make up for the limitations set forth by a butterfly or gravity damper. These use a fabric sleeve attached to a metal sleeve. The fabric sleeve will allow the air to pass through without restricting airflow.
This type of damper works more efficiently than other kinds of dampers in that they prevent unwanted airflow without reducing the efficiency of the system. They are also silent, so you don't have to deal with hearing the sound of metal banging against itself and are very versatile so they can be installed in a wide variety of applications.
Cape backdraft dampers are perfect for use in homes and can withstand temperatures up to 160 degrees. They are also economical and can easily be added to any vent. The best uses for them are in bathroom fans, dryer vents, low air flow HVAC systems and water heaters.
Using air flow regulation should be at the top of every homeowners list with rising prices in electricity as well as other homeowner costs. These can drastically reduce the amount of hot air entering your home in the summer, while keeping the cool air inside. As a result your air conditioner does not have to work near as hard.
Any vent or fan leading outside is capable of having a backdraft, bringing unwanted air into the room. With backdraft dampers, you can easily reduce the amount of this air, while saving money, increasing air quality and increasing the life and effeciency of your HVAC systems.