Most often when we are talking about room smoke eaters, we are either looking at a residential situation or a break room in a commercial setting. For jobs like this, I still refer back to air exchanges per hour. Very little changes from the way we spec out a commercial bar or restaurant, we’re just dealing with a smaller space.

To calculate air exchanges per hour, use the following formula:
( I’ll include an example)
L= Length
W= Width
H= Height
CF= Cubic Feet (of air)
ACPH = Air Changes (or exchanges) Per Hour
Measure your room (in feet) and work the following equation:
L X W X H = CF

(example: 10 X 12 X 8 = 960 Cubic Feet)

Now, work the following equation to find out how many CFM (cubic feet per minute) you would need to complete on air exchange per hour:

CF / 60 = CFM for 1 ACPH
(example: 960 / 60 = 16 CFM for 1 ACPH)

Next, figure how many air changes per hour you will need to handle the amount of contaminates and pollution in your room:

4-6 ACPH = Light Contamination (dusts, pollen, etc.)
6-8 ACPH = Light to Moderate
8-10 ACPH = Moderate (light occasional smoking, pets, etc.)
10-12 ACPH = Moderate to Heavy (1-2 moderate smokers)*
12-14 ACPH = Heavy (heavy smoking by 1-2 smokers most of the time)
14-16 ACPH = Very Heavy (2-4 heavy smokers or cigar smoke)

*(example: 16 X 12 ACPH = 192 CFM needed for 12 air changes per hour)

The above example is for calculating how much air flow you would need in a single room to reduce secondhand smoke, other factors to consider is the actual air filtration technology you will use.

Mechanical filters, such as HEPA or electronic collector cells only remove smoke particles. You must use several pounds of granulated gas phase media, such as carbon and potassium permanganate for the removal of chemical fumes and odors.

Also consider the fan speed settings on the machine you are considering, nobody like the noise level of any air cleaner on high speed, it is always best to size an air cleaner to handle the job at a medium setting. This also leaves room for catch-up or heavier than anticipated conditions.

Another thing to consider is that if you are using media filtration, such as HEPA, the airflow of a machine will greatly decrease over time, due to the filter loading with particles, which decreases airflow.

Lastly, remember that air purification dealer and manufacturers often overstate their airflow and state the CFM rating of the fan and blower, this is usually done before the filters are in place. A unit that says it has 560 CFM, more realistically has about 400 CFM with brand new filters, expect that to drop to about 300 after a few months of use.

For the above example, I would recommend the Smoke Muncher XL Deluxe. It could easily handle the airflow requirements at a medium speed and contains 26 pounds of activated carbon treated with potassium iodide.

If you need any help sizing a room or selecting the correct model, click the comments button below and I will be happy to answer your questions.