If you are wondering what size or how “strong” of an air purifier you need, these two calculators will help.
To properly size an air purifier or filter for your home or room, the main value you are looking for on an air purifier’s specs is how much air it moves. This will be provided by the company as the CFM (Cubic ft/Minute) value. Think of this as the fan size.
The First Calculator: Calculate What Size Air Purifier you Need
In the first calculator, you will find out what CFM value you need for your room size.
You need to add your desired or ideal Air Exchange Per Hour (ACH). This is how many times you want the unit to overturn (and filter) the air in the room per hour.
This calculator will tell you what (minimum) CFM value you are looking for and then below is a list of air filters that meet that requirement.
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Air Purifier to Choose based on Result of Required CFM from the Calculator
(Note if the required CFM is over 400 you will need more than one unit, I recommend calculating each room at a time, not the whole house).
PCO Models Best for Mold Reduction:
High Carbon (and other Sorbent Material) Best for High Offgassing:
The Second Calculator: Calculate How Much Air is it Cleaning
Below, the second calculator can tell you how many air exchanges per hour you are getting from an air purifier you already have, or one you are looking to buy, based on the size of your room.
Most experts recommend a minimum of 4 ACH. ASHRAE (The American Society of Heating, Refrigerating and Air-Conditioning Engineers) recommends a minimum of 4 ACH for patient rooms in hospitals, 5 for intensive care units and 25 for operating rooms.
These two calculators helped you find out your ACH to CFM calculation and your CFM to ACH calculation.
Corinne Segura is a Building Biologist with 8 years of experience helping others create healthy homes.
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