The importance of replacing your HVAC air filter

Clean air filters keep your HVAC system and the air you breath clean!

Your HVAC (Heating, Ventilation and Air Conditioning) systems air filters should be changed not when they're dirty but on frequently planned intervals. Your home's air filters are like your cars oil filter. Only clean oil works effectively as a lubricant. If you wait to change your car's oil and filter when it’s dirty, the performance and fuel efficiency of the engine decreases. This is the same for your home's HVAC system.  

There are many different kinds of air filters. Each has pros and cons. Below  is a list of most filters available from cheapest to most expensive:

• 1" unframed spun plastic cut from bulk material.  This material is the cheapest.  It does not have a frame so it fits poorly and allows many particles to escape the filter.
• 1" framed spun fiberglass.  These are usually blue or white.  They are low cost but do not capture small particles.  They must change often (monthly).
• 1" framed pleated paper media.  These are usually gray or white with deep one inch pleats. The cost can be up to five times a fiberglass filter.  These are preferred as the most effective filtration material.
  
• 1" washable media.  These area usually black in a metal silver colored frame.  These last longer but must be washed and dried monthly creating quite a hassle.
• Return air grill HEPA filter system.  This a four inch deep pleated filter with a 1” extension frame that fits existing return air grills where the air is returned to the HVAC system.  They are more costly than 1” pleated filter but last much longer and filter more material resulting in fewer changes per year.  Typically, this type of filter is changed twice a year.
  
• The in-line HEPA filter fits in box next to or under the HVAC system.  This system last much longer than a standard 1" pleated filter thus requires fewer changes per year.  However, the initial installation of the in line box is more costly to install.
• Electrostatic filter systems.  These are electrically charged so there is a risk of electrocution.  Since the system is permanent, it lasts longest but is costly to install but this system filters the most material.
  

Filters should always be changed or cleaned based on the manufacturer’s recommendations. It is probably the easiest thing to do to keep your HVAC system clean, running efficiently, reduce your maintenance costs and extend the overall life of your system.


Most homes have the filters located as the first point of air intake but some have them located near the main HVAC system as an inline box. If yours is not part of an inline system, it will be located on a wall, on the ceiling, under the furnace or more rarely, in the floor. It is almost always located near the HVAC unit’s thermostat. Since room temperature air is pulled from the house into the return plenum where the filter is located to be heated or cooled, measuring the air temperature with the thermostat near the return is just makes sense.


You home's filters are installed using one of three methods. In most cases, the filter is located in a return air grill that folds open to reveal a one inch frame that holds the filter. If the furnace is in a closet, it may be located under the furnace’s blower unit.  These are usually either held down with a U-shaped wire or end clip.  A HEPA (High Efficiency Particulate Air) is usually slid into a 4" or 5" wide in-line HEPA filter box either under the blower unit or before the furnace (if the system is horizontally oriented). HEPA filtration is considered the best type of filtration since it stops the smallest particles from entering the core of the HVAC system. Only electrostatic systems can filter out more than a HEPA filters. In most cases, the in-line filters are simply slid out and new filters slid into their place. By far, the most difficult filter to change is the one that fits under the blower and is held down by the U-shaped wire or end clip. This design seems to be weak and allows the edges of the filter to be pulled up by the vacuum of the blower when the unit is on.


It’s always a good idea to have more than one filter on hand for each size your house uses. This will save you from having to make special trips to the hardware store for this frequent and very important task. Filters are not created equal so decide which system is right for your home but try to choose a filer with a sturdy frame. I personally use a Honeywell 4” HEPA return grill filters that fit in my home’s ceiling return air grill. This is a specially designed filter that uses the in-line HEPA concept but allows you to insert in to a standard 1” return air frame. They are not easy to find and I’ve never seen one at a hardware store. I use “return air grill media filter" as keywords to search the Internet for companies that sell this unique filter. Buy a case at a time and you’ll have several years of filters on hand.

Regardless of they type of house you have, there are some necessary tasks you will have to do stay on top of things.  Learn more and keep up with your house with a free My Healthy House.com profile.  Stay tuned and make your house the best it can be.  

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