3M Filtrete 1" Air Filters Comparison Chart:

	Dust Reduction	Dust & Pollen	Micro Allergen	Ultra Allergen	Ultimate Allergen	Elite Allergen
Description:	Entry Level	Basic	Good	Better	Best	Best
Prices   Starting From:	$5.99/filter	$6.99/filter	$10.99/filter	$14.99/filter	$15.99/filter	$17.99/filter
Available in:	17 sizes	24 sizes	31 sizes	32 sizes	22 sizes	7 sizes
MPR Rating:	300	600	1000	1500	1900	2200
MERV Rating:	7	8	11	11	12	12
* Efficiency:	60%	70%	80%	90%	93%	94%
Pressure Drop:	0.15	0.14	0.21	0.19	0.21	0.21
Captures:	Large allergens, such as: household dust, and pollen.	Large allergens, such as: household dust, pollen, dust-mite debris, and lint.	Large allergens, such as: household dust, pollen, dust-mite debris, mold spores, and pet dander. Small allergens, such as: smoke, smog, and bacteria.	Large allergens, such as: household dust, pollen, dust-mite debris, mold spores, and pet dander. Small allergens, such as: smoke, smog, bacteria, and particles that can carry viruses.	Large allergens, such as: household dust, pollen, dust-mite debris, mold spores, and pet dander. Small allergens, such as: smoke, smog, bacteria, particles that can carry viruses, and particles that can carry odors.	Large allergens, such as: household dust, pollen, dust-mite debris, mold spores, and pet dander. Small allergens, such as: smoke, smog, bacteria, particles that can carry viruses, and particles that can carry odors.
Summary:	Most economical Filtrete Filter available	Lowest pressure drop of any Filtrete Filter	Most economical "High-Performance" Filter	High-Performance Filter	Premium High-Performance Filter	The absolute best quality filter, available in select sizes

About 3M Filtrete 1" Air Filters:
3M Filtrete filters contain electrostatically charged filter media made of polypropylene and polyolefin plastic, and capture particles that measure between 0.3 - 10 microns in size. The electrostatic properties cause the filter to act like a magnet, helping it to attract both large and small particles into the filter's pleated fabric. 3M Filtrete filters, when clean and new, outperform all other fiberglass, washable and non-electrostatic 1" residential air filters.

MERV and 3M Performance Rating:
MERV (Minimum Efficiency Reporting Value) is a number from 1 to 12 produced from an air filtration test designed by the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE). The MERV rating is designed to help you compare the effectivenes of various air filters, with a higher MERV rating indicating better filtration performance. 3M also produces their own independent ratings which focus instead on a filter's ability to capture the smallest particles and allergens measured in the ASHRAE test. Using particle data between 0.3 and 1 microns in size, the Microparticle Performance Rating (MPR) is 3M's way of demonstrating their filter's superiority at capturing the smallest microscopic particles. A higher MPR rating indicates a more effective 3M Filtrete filter.

Recommended Replacement:
Filtrete furnace filters should be replaced at least once every 3 months. When clean and new, Filtrete filters do not restrict airflow. After the Filtrete furnace filter has been in your system for 3 months, and depending on your usage and environment, it may begin to restrict airflow. Certain conditions in your home will significantly add particles to the air causing the filter to capture more particles than usual. This will shorten the filter life to less than 3 months and reduce the effectiveness of the filter to capture particles. These conditions include: Dirty Ductwork, Construction Work, Sanding Projects, Pets, Burning Candles, Tobacco Smoke and Fireplace/Wood-Burning Stove Smoke. In addition, running your furnace or air conditioning fan continuously will help clean the air in your home more effectively, but could further shorten the life of the filter. So, if you use a Filtrete filter under these conditions, it could begin to restrict airflow, especially in energy efficient furnace and air conditioning systems. In these cases, it is recommended to change the filter more frequently. Actual filter life will vary depending on your living conditions.

To determine when the filter needs to be changed, hold the filter up to a light source. If you cannot see any light through the filter, it should be changed even if it has been used less than 3 months.