We tracked down another good article on angieslist and we decided after reading it, it is just what the furnace doctor ordered.
This article was written by JB Landers, Angie’s List Contributor. It is kind of a long read, but be sure to click the Google+ button and leave a comment below.
The Environmental Protection Agency (EPA) reports that indoor air quality rates among the top five environmental health risks. Air-tight construction and home insulation contribute to this because they eliminate incidental home ventilation.
Consequently, you have two options to improve indoor air quality: allow clean exterior air into the residence to provide ventilation or use an air cleaning device that removes indoor pollutants.
You can choose between two types of air cleaning devices for the removal of airborne pollutants: electronic air cleaners and mechanical air filters. Air filters consist of porous membranes that allow air to flow through while trapping dust, pollen, dust mites, pet dander and some mold spores.
To help measure the efficiency of filters installed in the duct work system of heating and cooling units, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has a rating system called the minimum efficiency reporting value (MERV). These ratings range from 1 (lowest) to 20 (highest), and shows three things:
- the ability of the air filter to remove particles
- the ability of the air filter to resist airflow
- the product’s expected operating life
Mechanical filters possible for residential heating and cooling systems come in four varieties.
Flat-paneled fiberglass air filters
Usually carrying ratings of 1 to 4, flat-paneled fiberglass air filters consist of a disposable filter made of layered fiberglass fibers. The material forms a filter media for filtering the air. A metal-like grating reinforces and supports the fiberglass material and helps prevent the filter from collapsing.
Inexpensive air filters mostly provide protection for heating and cooling components and not for cleaning the air. The filters have a medium efficiency rating for capturing larger airborne particle and a low efficiency for the filtration of dust mites, viruses, bacteria and dander.
Pleated polyester filters
Similar to fiberglass filters, disposable pleated polyester filters have a sizable surface field and a rating of 5 to 13. The medium efficiency rating makes them efficient at filtering small to large particles. Filters with a rating of 7 to 13 provide a level of effectiveness compatible with absolute high-efficiency particulate air (HEPA) filters, but at a lower price point.
These filters also have less airflow resistance compared to HEPA filters and support quieter operation of the blower fan. Pleated filters also come in a higher efficiency product with a rating of 14 to 16. They have the physical appearance of true HEPA filters and are often confused with HEPA products.
High-efficiency particulate arrestance (HEPA) filters
HEPA filters are recognized by the Occupational Safety and Health Administration (OSHA) and EPA as the ultimate product for cleansing airborne particles. HEPA products filter air at a very fine level, blocking elements that are 0.3 microns or larger. These filters catch 99.97 percent of all particles.
HEPA filters have an efficiency rating of 17 to 20. Most residential heating and cooling systems can’t accommodate HEPA filters because of the product’s dimensions and resistance to airflow. If you’re interested in HEPA filtering, call on a licensed heating service provider to configure their heating and cooling system to accept these filters.
Washable air filters
Permanent and washable filters are fabricated from plastic or metal frames. These products have a few layers of polypropylene weave or wire mesh material that stops certain pollutants. The durability of the filtration material makes it cleanable and reusable. According to Daniel Sinclair of Angie’s List 2012 Super Service Award winner Sinclair Heating, Cooling & Plumbing of Lubbock, Texas, washable air filters come with some major drawbacks:
- They’re usually rated only 1 to 4 on the MERV scale. “If your house is exposed to smaller particles like pet dander, cigar smoke or hair spray,” Sinclair writes, “a washable air filter may not be as effective as a higher-rated disposable filter.
- Maintenance is a pain. “Once you’ve washed them, you’re not supposed to simply dump the water out,” he writes. “Because that water was exposed to bacteria and other particulates, it’s considered a wastewater hazard and should be disposed of appropriately — creating extra work for you.”
- They can get moldy. When you wash these filters, they’ll take a long time to dry. If you replace them while they’re still damp, they may develop fungi that your HVAC system can blow througout your home.
- They cost more than a disposable filter. So you’re paying more for a filter that works better.
We hope this article helped shed light on your questions about furnace filters.
Don’t forget to contact us today with all your Greenville SC heating and cooling repairs.