Aired on: 2012.08.23
How do Carbon Filters Work? How to pick the right size Carbon Filter... Does it have to fit your fan? for that matter, how do you decide on fan size? This is what we talk about today on Lex's World. Carbon filters use a process called Adsorption... air passes through ground up charcoal that's been treated with oxygen to achieve a 'cleansing' effect on air that passes through it. So long as you recharge the Carbon Filter with positively-charged, oxygen treated charcoal on occasion, it works great in eliminating odors. If it is correctly fitted to both the exhaust fan and the room it is in, it will work amazingly!
EXAMPLE FOR PICKING A FAN & CARBON FILTER:
Your room measures: 5 feet long... by 5 feet wide... by 7 feet tall.
Step 1) Figure out Volume in Cubic Feet: 5X5X7 = 175 CF (Cubic Feet)
All Fans & Carbon Filters are rated by how much air they can move. The rating is in Cubic Feet/Minute (CFM), so figure out how many CFMs you need. Aim for AT LEAST 25-30 full air exchanges per hour. High impact growers do it 60 times an hour.
Step 2) 175 Cubic Feet X 30 times/hour = 5250 Cubic Feet per Hour, Divide by 60 minutes: 87.5 CFM
You now know that you need a fan & Carbon Filter that move AT LEAST 87.5 CFM. Any 4" inline fan will have more than enough power for this. Then just find a 4" carbon filter that is rated for at least 87.5 CFM (this would be a relatively small one). For extra credit you can go as high as 175 CFM on both of them.