What You Need to Know About Your Furnace Filter


Furnace filters are a little-known but important part of the heating and cooling process. Furnace filters, in the context of air conditioning and heating systems, work to remove excess dust, dirt and debris from the air before it passes through to your vents.

This is one of those tasks that falls under the category “it may not seem important, but if you don’t do it, it could have serious consequences.” If there are young children or elderly people at home, it is especially important to make sure that their furnace filters are changed as often as possible.

Furnace filters are not optional as they play a critical role in the running of your furnace. They must be maintained regularly and replaced as necessary to ensure that air quality is optimal throughout your home.

Here is everything you need to know about your furnace filter!

Why You Should Change Your Furnace Filter

Homeowners should be diligent about changing their furnace filter regularly (usually once every 1-3 months). And while this is an easy task that doesn’t take more than a couple minutes, it’s surprising how many homeowners don’t change their filters as often as recommended.

But when they get dirty or clogged, they can also cause problems like:

  • An increase in allergens that could cause asthma attacks or other health issues for those sensitive to dust and pollen
  • A decrease in air flow due to pressure drop caused by clogged filters
  • An increased risk of fires because furnaces have to work harder if their filters are clogged
  • Prevent particles from getting into your HVAC system, where they would eventually collect in the evaporator coil

When to Change Your Furnace Filter

Furnace filters are designed to be changed every 1-3 months or so -- typically during your scheduled furnace service visits. The length of time that you go between changes will depend largely on the quality of air in your specific area. For example, if you live near a construction site where there is much more dust and dirt in the air than average, you should change your furnace filter more often. If you have pets, you will want to change that filter regularly.

Filters are not created equal! If you have high-quality filters in your home, they should be changed at least once each heating season. On the other hand, low-quality filters may need to be replaced every month or two—or even more often.

How Can I Tell When I Need To Change My Furnace Filter?

The air in your house is drawn into the return duct work and then heated before being pumped back into your house by a central heating system. The air is pulled through that furnace filter that captures larger particles such as dust and pet dander.

Over time, your filter will become clogged with these particles and you'll find that the cooling or heating system begins to work less efficiently.

You will know when to replace the filter by using the following indicators:

  • If you can see through the filter easily (or look at the manufacturer's recommendations for your particular filter), it is time to be replaced.
  • If you shake or tap the dust off of the filter and some kind of granular debris falls out, you should definitely replace it.
  • If you see more dust around the house, don't be afraid to replace the filter.
  • Sneezing? Sounds like it's time for a new filter.

Is There A Difference Between Furnace Filters?

Absolutely! The filtration media and the frame of the filter can be constructed from a variety of materials including fiberglass, cardboard, mesh, foam and pleated paper to name a few. In addition to this, there are different ratings for filters that help to let you know the filter's ability to block things like bacteria, pollen and mold.

Be sure to use an appropriate filter for your HVAC system. Different types of filters are designed to catch different particles in the air. For example, a basic panel filter is not appropriate for allergy sufferers or households with pets.

What Should I Think About When Choosing A New Filter?

Filter size is very important! To ensure your furnace filter provides the correct air flow for your system, you must have the right sized filter. This information can be found on a sticker located on or near your current filter. It will also be printed on the side of the new filter package.

Pleated filters can remove more dirt since they have larger surface areas to collect it. An electrostatic pleated filter offers significantly better filtration compared to a non-pleated one.

Discard any filters that you can readily see through.

A Clean Filter Saves You Money!

Consider the following: A clogged filter makes your equipment work harder, which means you'll use more energy. A dirty furnace filter can significantly reduce the efficiency of your heating equipment.

A clean air conditioning, heating, and ventilation system is more efficient at delivering heated or cooled air throughout your house. Your system will run less frequently, which means it will last longer!

What's the bottom line? A clean furnace filter means savings on energy bills and a system that requires less maintenance.

Not to mention that avoiding having to make an emergency service call to replace or repair expensive parts like evaporator coils can be worth it to you in the long run.

Furnace Filters: The "Do's" & "Don'ts"

DO read the instructions on your furnace filter carefully; they should tell you how long the filter will effectively clean air before you'll need to change it.

DO consider purchasing high-quality furnace filters that are designed to last longer; these usually cost more but can save you money in the long run (and spare you from having to make emergency trips to the store).

DO set a reminder to check your heating equipment's performance every couple of weeks to see if your filter needs changing.

DON'T neglect to change your furnace filter when needed, even if it still looks clean! Remember, a dirty air filter makes your furnace—and your heating and cooling system—work harder, not smarter!

DON'T use NO filter, always put some kind of furnace filter in the appropriate place

DON'T leave dirty filters laying around to spread the dust and pollen around again


If you have any questions about how often to change your furnace filter or which kind of filter is best for your home, contact Craig Plumbing, Heating & Cooling. We can help ensure that your home stays comfortable.

To be certain you never miss a furnace filter change, sign up for our Service Club!

Craig Plumbing, Heating & Cooling offers a Service Club annual inspection, which is the key to keeping your plumbing and HVAC systems in great working order.