by James Dover, M.D.
Allergens and air pollution can best be treated by avoiding exposure to them. This can be accomplished by correctly designing the bedroom exposure, and by using air purifiers to reduce exposure within the home.
Air purifiers come in all shapes and sizes, and can use one or several collection techniques. What really counts is not their appearance, but their effectiveness in cleaning the air where you need it cleaned and to the degree it needs to be cleaned. The commonly asked question is which one is best: a single portable room air purifier or one installed in the home’s central heating and cooling system.
Approximate efficiencies of central furnace filters:
- Standard furnace filters – 5%
- Electrostatic filters – 75%
- Electronic filters – 95%
- HEPA filters – 99.75%
A highly efficient HEPA filter, high CFM (cubic feet per minute) portable, will be more effective in the room where it is located than a central system. There are scenarios that can go either way, but the portable unit has some features not available with a central system, such as:
- Usually less expensive than an efficient installed system.
- Can be moved with the people to do a superior cleaning job in the room where time is spent.
- Can “visit” friends, relatives, office, or motel.
- Can move with the family to a new home more easily than a central system.
- Can have a lower electrical operating cost, considering the large heating/cooling blower must be operated continuously with central cleaning.
- There are no installation costs involved with portable units.
- Can filter our odors or chemical smells better due to carbon filters that are replaceable.
Remember to look for this information when selecting your air purifier:
- CFM. Cubic feet per minute tells you how much air can be cleaned each minute. The larger the CFM rating, the larger the area cleaned.
- RSP. Respirable size particle is measured at 0.3 micron, which is the range most likely to be deposited in the lungs.
- CADR. Clean air delivery rate measures the volume or air that is moved through and treated by the purifier. If no air moves through a 100% efficient air purifier, the effect is no air cleaned. An air purifier with a larger CADR number can always maintain cleaner air in a space or room than one with a small CADR, regardless of the size of the room.
- Warranty. Most quality units have a lifetime warranty for central units and replaceable filters for portable units.
Above all, do not waste money on cheap products which deliver insufficient airflow, require frequent service or filters, or may be poorly constructed.
Posted in: Home Environment