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This Is Why You Need to Change Your Furnace Filter


As a Louisville homeowner, one of the most important things you should do is changing furnace filters throughout the year. Unfortunately, too many of us forget or skip this important job, which causes problems with HVAC equipment along with home comfort.

To drive home how important changing furnace filters is, our NATE-certified technicians share the many issues that are caused by dirty filters. We also explain how often to change your filter based on various factors that apply to your household.

Jarboe’s Heating, Cooling & Plumbing cares about your comfort and your comfort systems. From maintenance to help you avoid issues to quick repairs that undo damage, we are here to help. Contact us today to schedule heating service in your Louisville home.

What Is a Furnace Filter’s Job?

Furnace filters are designed to capture dust, dirt, debris, and more that travel throughout our homes via the indoor air supply. Many people mistakenly believe a furnace filter does this job primarily to improve indoor air quality.

In fact, the main purpose of the furnace filter is to keep all those things out of your HVAC system – cleaner air is more of a bonus! Depending on the filter you use at home, it can have a great impact on air quality, but either way, it primarily serves as a safeguard for your equipment.

When Changing Furnace Filters Is Necessary

How often changing furnace filters needs to be done in your home is probably different from your neighbor’s filter changing schedule. This is because there are several different types of filters and several different factors that make it so a filter may need a change sooner or later. Just take a look at the filter section of your local home improvement store and you’ll see what a wide selection of replacement filters there are on the market. The differences each of these filters carry impacts how often you must change them.

Changing furnace filters needs to take place anywhere from once per month to once per year – sounds like a pretty wide range, doesn’t it? Thankfully, you don’t have to guess when it’s time to replace your furnace filter. A good place to start is by checking the product information that was in the packaging when you purchased your new replacement filter. The manufacturer states how frequently your filter usually needs to be changed.

While different from one home to the next, in general changing furnace filters should happen on this schedule:

  • Replace 1- to 2-Inch Filters Every 1 to 3 Months
  • Replace 3- to 4-Inch Filters Every 6 to 9 Months
  • Replace 5- to 6-Inch Filters Every 9 to 12 Months

Thicker filters have more surface space and filter media to trap airborne contaminants, so they last longer than the thin, 1-inch disposable filters. Aside from filter thickness, filter efficiency also impacts how often it will need a change. Filter efficiency is measured by MERV – minimum efficiency reporting value. Filters with a higher MERV rating typically last longer than those with lower MERV ratings.

Guess what – that’s not all! These household factors also impact how long your furnace filter lasts and how often you need to be changing furnace filters:

Number of People in the Home

Homes that house large families need to be changing furnace filters more frequently than in homes where only one or two people live. With more people in and out, using products, and more, more contaminants are introduced into the home’s air to be removed by the filter.

Pets in the Home

Pets are a significant source of airborne contaminants in the home. Their fur and dander are easily circulated as air moves through the house. Households with pets see about 30 fewer days of service life from their furnace filters per pet, compared to households with no pets.

Indoor Air Quality

Indoor air quality equipment like air cleaners and air purifiers do a great job at removing contaminants from your air supply. If you utilize these systems, there is less contamination for your furnace filter to snag, so it lasts longer. In homes with poor indoor air quality and no indoor air quality systems, filters just don’t last as long.

Allergy Sufferers in the Home

Anyone with allergies will tell you just how miserable the symptoms can be. Contaminants in the house can be a cause of many people’s allergy symptoms. If someone in your home suffers from allergies, it is wise to be changing furnace filters at a more frequent interval to help ensure contaminants are regularly removed from the indoor air supply.

HVAC System Use

During times of the year where heating and cooling systems run in full swing, furnace filters don’t last as long. As they cycle more frequently, there are more opportunities for the filter to capture contaminants and they become full of them sooner. Most Louisville homeowners find changing furnace filters necessary more often in the summer and winter when these systems run throughout the day, rather than in spring or fall when we use them sparingly.

What Does a Dirty Filter Do?

If changing furnace filters isn’t made a priority, your household is destined to experience some pretty troublesome problems. Dirty furnace filters harm the HVAC systems inside Louisville homes, cause discomfort among occupants and generally contribute to worsened indoor air quality.

System Damage from Dirty Filters

As mentioned above, the primary purpose of a furnace filter is to stop airborne contaminants from reaching the interiors of HVAC equipment. Your furnace and air handler are filled with several delicate components that need to be protected from dust, dirt, and debris.

When a filter is dirty, it is not effective at removing circulating contaminants. So, these contaminants are able to cycle through the equipment, where they settle on components. As they build up, contaminants impact performance and force the system to work harder and use more energy. Debris buildup inside the unit also leads to damage which requires HVAC repairs to remedy.

Furnace filters also help the home’s HVAC equipment maintain adequate airflow. When changing furnace filters is forgotten, air isn’t able to freely circulate through the system. This causes the furnace or air handler to use more energy to move air through. This sets off a sort of chain reaction – the system works harder, uses more energy, raises utility bills, and sustains damage.

Good air movement is also needed to keep temperatures within a safe range inside your HVAC system. When airflow is restricted due to a dirty filter, interior temperatures rise – often to the point of overheating. At this point, the system shuts down. Then starts back up again later, but quickly shuts down again, and so on.

This is a problem we call short cycling. The name reflects the shortened heating or cooling cycle the system produces. Not changing furnace filters as often as they should be is one of the top causes of short cycling. Short cycling causes excessive energy consumption, discomfort in the home, damage to components, and even early system breakdowns which require full system replacement.

Contaminants in the system also cause issues with the condensate drain. A byproduct of operation, condensation typically exits the system with ease through the drip pan and condensate drain. However, when contaminants get inside the system, clogs occur which prevent proper condensate drainage. The result is water damage as condensation spills out of the drip pan. Also, as this excess moisture now has no way to escape your home, the indoor air stays more humid, contributing to further discomfort.

Comfort Issues Caused by Dirty Filters

The system issues that result when changing furnace filters is overlooked, comfort issues build indoors. The airflow restriction caused by a dirty filter prevent living areas from receiving the heating and cooling they need to remain comfortable. It becomes difficult to maintain temperatures inside, and hot or cold spots may arise.

Without the ability to catch contaminants, a dirty furnace filter causes indoor air quality to decline. You’ll notice asthma and allergy sufferers encounter more triggers inside the home. Other family members may experience problems like respiratory symptoms, itchy eyes, runny noses, and more. Also, with more debris circulating through your home, more debris come to rest in your living areas. It becomes harder to keep these areas looking clean, despite constant chores – who wants more of that?!

HVAC Help from Jarboe’s

Jarboe’s Heating, Cooling & Plumbing wants our Louisville neighbors to understand just how important changing furnace filters really is, to both your HVAC system and your personal comfort. Now that you are aware of the serious issues a dirty filter can cause, we hope that you will make changing furnace filters a part of your regular home maintenance routine.

In addition to changing furnace filters, your system needs yearly maintenance to clear away debris and deliver other important care that improves performance and efficiency. If a dirty filter has already caused any of the issues we mentioned above, don’t delay in scheduling HVAC repairs – we work to resolve these issues to prevent further damage to your system and to restore comfort inside your home.

For HVAC repairs and maintenance, call Jarboe’s today.

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