Choosing a Kitchen Exhaust Fan
Kitchen exhaust systems work through the use of a powerful fan that sucks air from your kitchen and redirects it elsewhere. According to DoItYourself.com, you should always choose a fan that vents to the outside, as fans that vent into attics can be potential fire hazards. The most sanitary fans will also be equipped with filters or screens that can be easily removed for cleaning. While some kitchen exhaust fans are designed for ceilings and utilize the principle of hot air rising, others are designed to operate in hood-like structures that are positioned directly over gas or electric ranges. According to AskTheBuilder.com, to determine how much power or output your ceiling kitchen exhaust fan will need, you can simply take the area of the kitchen floor (200 square feet, for example) and multiply it by two to find the appropriate CFM or cubic feet per minute level (you would need a fan that can suck 400 CFM of air in this instance). According to DoItYourSelf.com, for fans being installed directly over ranges, you will want a fan with a rating of 100 CFM for every 10,000 BTUs (British thermal units) your range produces.
No matter what type or size of kitchen exhaust fan you choose, you will need to install ductwork from it to the outside of your home. According to AskTheBuilder.com, the best strategy for installing a do-it-yourself kitchen exhaust system is to have the ductwork extend out through the roof of your home. You can then place a special valve cap on top, which will allow exhaust to flow out, while preventing rain and other precipitation from coming in. Make sure all the joints of your ductwork are covered with a specialized foil duct tape to ensure that no air escapes. Also, avoid making 90-degree bends in your ductwork whenever possible, as this will disrupt airflow.
One common problem with kitchen exhaust systems--especially ones with high-output fans -- is that too much air can be sucked out of your home. This is especially true in more modern homes that are virtually airtight. When this happens, dirty air from chimneys and vents will try to replace the air that has been sucked out. According to AskTheBuilder.com, you can install a makeup-air vent to counteract this problem, which will cycle in fresh air from outside.