Filtering the air in your home

Murphy Giegerich CM • Indoor Comfort Team

Indoor Air can be up to 10 times more polluted than outdoor air.

Filtering the air in your house is important to improving or maintaining a healthy indoor environment. It also will protect the HVAC (Heating Ventilation and Air Conditioning) equipment and furnishings, allowing full-equipment efficiency and trouble-free maintenance.

I have seen many service calls that could have been prevented due to partially or fully clogged filters, and too often, these calls lead to expensive repairs. There are two basic categories of filtration options for your residential HVAC equipment – pleated or fiberglass filters and electronic-type filters.

Get the filter that is best at trapping the dirt in the air you breathe. A piece of plywood would make an excellent filter but would not let air pass, causing equipment damage.

So, it is a compromise of filtering the air but not becoming too restrictive to allow safe equipment operation within manufacturers specs. Pleated or fiberglass filters are rated in a MERV rating (Minimum Efficiency Rating Value). These values are numbered 1 through 16, with 16 being the most efficient at trapping dirt.

Electronic filters will use a magnetic field to charge the particles of dirt and use the principle that like magnets will repel, and opposite-charged magnets will attract in the capturing process of the dirt particles. This magnetic charge is created with a high-voltage static charge or field charge using some form of step-up transformer built into the filter. The electronic filter will have a media filter in front of the charging portion to remove large particles. These electronic filters are good at removing dirt down to a low micron size. Some filters have the capability of being higher than a Merv 16, with a low restriction to airflow, and are rated in what is called CADR (Clean Air Delivery Rate).

My fear is that homeowners put the most restrictive filter in they can afford, but even though these filters are good at removing dirt, they sometimes become too restrictive of the air passing through them and cause equipment damage and loss of efficiency.

Please seek out the advice of your installing HVAC dealer or service company to get the best filter you can without damaging the equipment.