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What Happens If You Don’t Change Your Furnace Filter?

Regular filter changes are an important component of maintenance for any forced air heating and cooling system, including furnaces, heat pumps, and air conditioners. What happens if you don’t change your furnace air filter when you should? Douglas Cooling & Heating explains what will happen to your HVAC system if it is left to run with a dirty filter in place.

What Happens If Your HVAC System Runs with a Dirty Filter?

Did you know that furnace air filters need to be changed on a regular basis? Changing your air filter is a must. This should happen as frequently as every month to every 12 months or so, depending on the air filter model in use. What happens if you don’t change your furnace filter and your system keeps operating with a dirty, old filter in place?

The furnace air filter’s role is to trap airborne contaminants so that they don’t make their way into the inner chambers of your furnace or air handler unit. Many homeowners believe their purpose is to trap air pollutants for the benefit of better indoor air quality, but this is actually just a bonus perk filters provide in addition to keeping the insides of your equipment clean. When the filter is full, it can no longer trap new particles from the air circulating through it, and these contaminants will be free to cycle into the HVAC equipment.

Let’s take a look at what happens if you don’t change your dirty air filter for a new one:

1. Dirt & Dust Accumulate Inside the Unit

Dirt and dust settling inside your furnace or air handler are what happens if you don’t change your furnace filter. These deposits build up on components inside the unit, restricting their performance. If you have a clogged air filter, the unit will draw more energy to power through this restriction and do its job, raising your energy costs. Your HVAC unit operates less efficiently and these parts encounter added stress that leads to more wear and tear, and eventually breakdowns.

2. Airflow Is Restricted

What happens if you don’t change your furnace filter is that the dirty filter will become a barrier inside the HVAC system, restricting air movement through the equipment and your home. In order to force air through the system and circulate conditioned air to your living areas, the HVAC system will consume more energy to do its job. As a result, your energy costs will increase because the system isn’t operating as efficiently as it should. The system will also experience added stress which takes its toll in the form of wear and tear and future breakdowns.

3. Equipment Overheats

With good airflow blocked by the dirty filter, the interior of your heating equipment can increase in temperature. When the inside of the unit becomes too hot, the limit switch will shut down the heating cycle in an attempt to protect the components from damage. Once the equipment cools down, it will be able to run again – but this issue will continue to repeat. Overheating can damage furnace components and prevent your home from reaching comfortable temperatures due to shortened heating cycles.

4. System Short Cycles

When your dirty furnace filters cause your HVAC unit to overheat and shut down, and then restart again repeatedly, is called short cycling.  Short cycling occurs when the HVAC system doesn’t run for the correct cycle length and the cycle ends prematurely.  Short cycling causes increased energy consumption as your HVAC unit experiences more starts and stops than it should. More frequent starts and stops also stress the system, increasing wear and tear, causing breakdowns and component failures, and ultimately forcing the unit to experience a premature total failure. Constant overheating with each cycle also damages components, leading to more repairs.  Replacing your air filter with a new air filter can help prevent short cycling.

Keep Up with Filter Change Needs

Ultimately what happens if you don’t change your furnace filter is that the system will run less efficiently, costing you more on your energy bills. Components will experience more stress along with wear and tear, causing them to break and require repairs or replacement. Ongoing operation with a dirty filter causes short-cycling, which will end up causing your HVAC system to break down for good and require total system replacement.

Avoid what happens if you don’t change your furnace filter and make HVAC maintenance a priority in your Birmingham, AL area home. Douglas Cooling & Heating offers heating and cooling maintenance tune-ups to care for your HVAC equipment in addition to the filter changes you perform throughout the year. Contact us today to schedule service.

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