Furnace filters – How, Why and What

Ok, let’s start at the beginning……….

The furnace should be maintained yearly by a service professional, (as recommended by the manufacture) and you need to be changing the filter regularly as well. There is or there should be a filter in your furnace. All disposable filters need to be changed on a regular basis.

A filter that is overly dirty can cause many problems and possibly a dangerous situation in your home.

  1. Reduced airflow to rooms in the house.
  2. Over heat the furnace, causing it to turn off at the limit switch.
  3. Cause smoke and possible fire.

The most common reason that emergency calls are placed to heating contractors is because of dirty furnace filters.   A dirty filter can actually cause the furnace system to shut down. Once the service technician is in the home and discovers that the furnace is not working because of the dirty filter, they usually find that the system has not been maintained and there is a lot of work needed to make the system work safely, effectively and lower the operating cost.

The How

Have you ever changed the filter in your furnace, or any furnace? Watch the video below for step- by- step instructions on how to do it.

If you have questions, call us 303-346-3466

The What

What type of filter should you buy? There are 3 basic types of filters available at the hardware store.

  1. Fiberglass (usually blue).  This type filter will keep the motor safe from large particles. This filter will not address cleaning particles out of the air you breathe.  A couple of reasons to use this filter are:  the furnace at your home is located in a crawlspace and/or your system has low airflow through the vents. This filter should be replaced in the beginning of the heating season and then again ½ way through.
  2. Media Filters (usually pleated).  This type filter is often advertised showing the MERV rating of the filter. The higher the MERV rating the more dust, dirt and allergens it will trap. This filter is typically 1” in diameter and should be changed every 1-3 months depending on the environment.  Check it every month to verify the condition of the filter. If it looks very dirty, change it and note the amount of time that the filter was in there.  It is not advisable to go to a high allergy arrest filter or MERV rating over 11 for a home heating system. As the rating goes up the ability to allow for good airflow goes down. A high MERV rated filter can reduce the temperature in those hard to heat rooms as a result of reducing airflow.
  3. Electrostatic  Filters. In the Metro Denver area, this filter is not recommended for home heating systems. As with the high MERV rated filters, this style filter is too restrictive. It inhibits airflow and can over heat the heat exchanger in the furnace.

The Why

Why do you care about changing the filter? There are two basic reasons:

  1. To protect the motor and other components in the furnace.
  2. To capture dust, dirt particles and allergens from the air.

The furnace system moves air throughout your home. Prior to the air going through the furnace, the filter captures dust and dirt. The type of filter you put in the system will protect the motor and depending on the type you choose, it can also improve the air quality in your home.

It is important to change the filter regularly. Prior to putting in a new filter, write the month on the side of it. This will help you to remember when it was installed so you can track how long it lasts.

Remember do your part to keep the furnace system running properly and avoid unexpected, costly breakdowns. Have the furnace serviced yearly and change the filter often.

Next month: CFL’s. Where to use them, how to dispose of them and what to do if you break one.

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