air filter

jon

I know to replace my central AC filters (20x20x1) about every 30-60 days and to do so with a pleated filter, but there are many different price ranges for a disposable pleated air filter from about $3 each to about $12 each. Which should I buy? Some are electrostatic, even though they are not washable or reuseable. I understand MERV ratings a bit, but is it worth paying double to go say from a Merv 6 to a Merv 8? Thanks for any enlightenment........

BillW@honeywell

MERV ratings...

are defined by ASHRAE Code 52.2-1999 as a standard based on their ability to remove particles from the airstream, and their resistance to air flow. The ratings range from 1 (least efficient) to 20 (most efficient). Theses ratings are based also on the size of the particles they can remove. .3-.10 microns (merv 13-20); 1.0-3.0 microns merv 9-16 and 3.0-10.0 microns (merv5-16).

Technical mumbo-jumbo aside, the basic retail special 1" disposable filters remove hair, string, dustbunnies; big easily seen stuff that will plug your coils right any. In other words, they are there to protect the equipment, and have no real air quality function. Try this... take one of these and shake some tablesalt out of your saltshaker, and watch it fall right through!

Retail pleated media filters can vary widely as to their merv ratings, so read the packages very carefully. The higher the number, the better.

Professionally installed media filters range from merv8 on up. The smaller particles, .3 to 1.0 are the ones that can cause the most damage, because they stay airborn longer, and are harder for the respiratory system to get rid of.

For example, our F100 basic media is listed as merv 8, with a 22% rating on the .3- 1.0 microns, 53% efficency on 1.0 to 3.0, and 78% on the 3.0-10.0 particles. The upgrade model, the F200, is rated at merv 11, with a rate of 47% for the smallest particles, 78% for the mid sized, and 92% for the largest. HEPA models are 99.97% effective at 0.3 micron particle size. The electronic air cleaner is professionally installed in your ductwork, (our F50F) and is rated at 73% for the smallest, 88% for the mid sized and 95% for the largest particles.

The cells of an electronic air cleaner are washed periodically, and there is no on-going cost of replacing media filter cartridges.