Which Air Filter do I Need?


Air filters keep the dust out, mitigate allergies, and keep pollution levels low inside our homes. Using the right air filter can even mitigate (but not remove) the effects of smoke or pet dander.  A quality filter will always lead to better breathing, regardless of the season. Not all filters are created to the same specifications.  Different materials and shapes are designed for different purposes, from full-scale medical scrubbing to simple residential filters meant to be disposed of after a few months.

Types of Filters

  • Fiberglass
  • Polyester
  • Electrostatic
  • High-Efficiency Particulate Arrestance (HEPA)
  • Washable

Ratings and Costs

There are two different ways to select an air filter for your home: By efficiency rating or by cost.  The size and shape of your filter is based on your current ventilation system, so there’s nothing to be decided there.  The rest is a balance of how much you want to spend on a filter compared to how sensitive you are to airborne contaminants.

Filters come in two different types: disposable and washable.  Most filters used by residences are of the disposable type.  Washable filters have the benefit of being reusable, by they typically have low Minimum Efficiency Reporting Values (MERV).  MERV ratings are a simple number between 1 and 20 that identifies how effective a filter is at removing particles from the air.

  • Fiberglass – Flat panel fiberglass filters are the most common filters for homes and apartments.  They’re effective at removing dust, large pollens, and pet hair from the air but aren’t the most effective filter on the market.  The inexpensive $1-2 price tag per filter makes them easily affordable, however.
  • Electrostatic – These filters use an electrostatically-charged cotton to capture smaller particles and pollutants.  They’re especially well-designed for homes with smokers or pets, as they’re capable of collecting particulates that a standard fiberglass filter will miss.  They’re more expensive, however, averaging $10.
  • Pleated Polyester – Unlike the previous two filters, polyester-based filters are folded into pleats.  These pleats increase surface area, helping to push the MERV rating for a polyester air filter up into the 10-14 range.  The increased surface area allows for a higher rate of airflow while still cleaning up the air as it passes through.  If you want the best balance of cleaning power and cost, polyester filters are the way to go.
  • HEPA – Hardy, long-lasting (they require replacement every year instead of every 3 months) and sporting an almost perfect MERV rating, HEPA filters are the most expensive on this list. Unfortunately, the major drawback is that they use a non-standard form factor.  Unless your ventilation system is designed to use a HEPA filter, it won’t fit.  These filters are standard for environments that require top-tier filtering, such as hospitals.

Thank you for making Service Legends the #1 provider of residential heating and air conditioning in the Des Moines area. A live and friendly customer care representative is ready to take your call 24/7 at 515-COMFORT (515.266.3678).

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