Asthma and Air Filters
Choosing an Air Filter
Ask the following questions before purchasing an air filter:
- Is it large enough? Will the unit clean the air in a room the size of my bedroom every four to six minutes at a fan speed I can tolerate? An adequate size is determined by the device's clean air delivery rate (CADR). The Association of Home Appliance Manufacturers (AHAM) rates air cleaners according to their clean air delivery rates; see the AHAM web site for details.
- How difficult is it to change (or clean) the filter? Ask for a demonstration. How often does the filter (or the two different filters) have to be changed (in an average home with a smoker, which is the worst case)? How much do the replacement filters cost? (Also check the cost when buying them online)
- What is the estimated cost to run the unit continuously for a year?
- How much noise does the unit make? This is very important for the HEPA units that include a fan. The CADR rating is only when you run the fan on the high speed, which is always the noisiest. Is it quiet enough to run while you sleep? (Turn it on and try it, even though you will probably be in a store and may not get a true sense of just how noisy it is in the quiet bedroom environment.)
If you or a loved one has asthma symptoms and there's a smoker in your home, an air filter is likely to improve your asthma control. If there is no secondhand smoke in your home, air cleaners may not help your asthma. If you are the one smoking, a room air cleaner will only help the nonsmokers in your home, not you. The bottom line on using air filters to prevent an asthma attack? If you’re a healthy individual living in a relatively unpolluted environment, there's probably no need to spend the money.