Sizing An Air Cleaner Using Expert Advice
Correctly sizing an air cleaner ensures that it can handle the demands of purifying your home’s indoor air. A portable air cleaner is typically used in those areas where individuals who are especially sensitive to airborne particulates spend the most time, such as in bedrooms or other enclosed living spaces. Room air cleaners may also be placed where the household air contains a higher contaminant load due to smoking or cooking fumes. Sizing an air cleaner is accomplished by considering the unit’s air change per hour (ACH) and its CADR (clean air delivery rate).
Air change per hour
Most health authorities recommended an indoor air cleaner with sufficient airflow to clean the entire volume of air in the room at least three times per hour. A bedroom measuring 12 feet by 14 feet with a standard eight-foot ceiling contains an air volume of about 1,350 feet. Three air changes per hour total 4,050 cubic feet. Air cleaners are rated according to the cubic feet of airflow per minute (CFM). Dividing 4,050 by 60 (minutes) produces a minimum recommended airflow of at least 67 CFM. For the maximum six air changes per hour in a room that size, a cleaner with an airflow of at least 135 cubic feet is required.
Clean air delivery rate
The CADR system developed by the Association of Home Appliance Manufacturers rates indoor air cleaners by considering a unit’s efficiency in removing three common pollutants. The system assigns a numerical score to express the speed in removing dust, tobacco smoke, and pollen from a room of a given square footage. An acceptable CADR for each of the three common pollutants should equal at least two-thirds of the square footage of the room. For example, an air cleaner used in a 120-square foot room should have CADRs of at least 80 on all three pollutants.
Call us for more details on sizing an air cleaner to your needs.
Our goal is to help educate our customers in Wilmington, Delaware and surrounding areas about energy and home comfort issues (specific to HVAC & plumbing systems).
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