The fall is when most of us in the heating belt fire up our furnaces after a warm summer. For those who don’t have central air conditioners, this is probably the first time in 6 months or more that the furnace has been running. Now is the time to prepare for the cold weather months and one needs to start by inspecting the furnace for any cracks or damage to the heat exchanger, clean out the dust that has accumulated over the past season and install a new filter. Now one has to decide which filter to use and what is the difference between MERV 7, 8, 11, and 13 or are the inexpensive filters fine to use.
First the basics, filters have been around for decades and everyone used the same basic throw away filters without much attention to the performance of the filter. Over the past number of years, the awareness of proper filtration has come to light. Homes are being constructed using materials that all but eliminate drafts and air seepage into homes causing indoor air pollution, stale air, and unhealthy environments. While filtration alone won’t fix the problem, we now have alternatives to the basic 89 cent filter. There are filters that eliminate allergens and ones that filter out the smallest of particulates. But which filter should one choose. The decision begins by understanding what the needs are of the home. But lets start with understanding just what does MERV mean and gain an understanding of the MERV ratings.
Minimum Efficiency Reporting Value, commonly known as MERV Rating is a measurement scale designed to rate the effectiveness of air filters. The scale is designed to represent the worst case performance of a filter when dealing with particles in the range of 0.3 to 10 microns.
Merv ratings range from 1 to 16 and measurements are in microns. Some of the common particles related to MERV ratings are pet dander, insecticide dust, smog, dust, viruses, wood, tobacco smoke, spores, bacteria and pollen.
Some of the most popular furnace filters found in residential use often have no MERV rating and are typically disposable panel type filters that do a fair job at controlling dust in a home because they do not stop particulates smaller than 10 microns.
Pleated panel filters outperform ordinary filters with higher efficiency and lower pressure drop allowing air handling systems to stay cleaner and operate more efficiently. MERV 5 – 8 filters are a popular choice for homeowners as they remove smaller particulates than panel filters. These filters will collect particulates as small as 3 microns and are a good choice for homeowners and are often used in commercial applications. MERV 7 and 8 filters in common sizes are widely popular and available at numerous retail outlets.
Filters with a MERV rating of 11 – 13 offer homeowners the highest level of performance in dust control, allergen relief, pollen, dust mites, pet dander, and mold spores. Often these filters are purchased through Indoor Air Quality specialty store on-line.
How Often Should I Change My Filter?
The frequency of a filter change can depend on many factors. These can include the outside environment, trouble with allergens, how long the furnace runs during the day, pets, and smoking. Inexpensive filters should be changed at least monthly as the loose effectiveness quickly with a lack of media surface to collect particulates. Pleated filters (MERV 7 – 13) have considerably more media surface and remove smaller particulates. These filters can last up to 2 – 3 months but should be checked monthly to ensure optimum system performance.
Visit us at www.iaqliving.com for all of your filter needs. We stock a full line of MERV 8, 11, and 13 filters in 1, 2, and 4″ widths.