What Happens If You Put Furnace Filter In Backwards?

furnace repair service

For your furnace to function optimally, you know you have to replace the filter. For experienced homeowners replacing the filter isn’t a problem, but it might be a problem for new homeowners that might install it backwards.

What happens if you put the furnace in backwards?

You might think nothing will happen, but nothing is further from the truth than this. According to furnace repair service providers, installing the furnace backwards comes with plenty of negatives that include:

Short cycling

Short cycling is when the furnace turns on and off faster than it should. You might get away with installing the filter backwards with a new furnace, but it will short cycle if your furnace is old. Sometimes the effect is so severe that fire starts.

When you let the furnace short cycle for a long time, you put the furnace under more strain than it should, which significantly reduces the appliance’s efficiency.

Reduced efficiency

When you install the furnace filter backwards, you impede airflow, which reduces the appliance’s efficiency.

Installing the filter backwards also means that the air flows around the filter, throwing a lot of dust on the evaporator coil. When there is a lot of dust on the evaporator coil, you have reduced efficiency.

Besides the dust covering the evaporator coil, it also coats the blower fan, blower motor, and other internal parts of the furnace which further significantly reduces your appliance’s efficiency.

Poor indoor air quality

Reduced airflow, short cycling, and increased dust make the house uncomfortable to live in. The situation is worse in newer homes that are designed to be airtight. Here you will have to clean and dust the house more often than usual.

Increased risk of mold growth

As mentioned above, a backwards filter leads to more dust getting in the furnace and reduced airflow. The unfortunate thing is that dust is a food source for mold.

This means the longer you live with the filter in the backwards position, the higher the chances of mold growing in your home.

Mold comes with plenty of health negatives such as increased allergies, respiratory diseases, and many others.

How can you avoid installing the furnace the wrong way?

There are two ways to do it. One is to invest in knowledge. You need to read or watch videos on how to install the filter properly. To know how to install the filter in your specific furnace, read the owner’s manual.

If you don’t have time for this, hire a professional to install it for you. The cool thing with hiring a professional is they not only replace the filters; they also inspect the furnace and fix any issues that might be present.

Understanding how the furnace works

The key to avoiding making a mistake is to understand how the HVAC system works. Airflow always goes from the return vents to the furnace where it’s re-heated.

The HVAC duct system works like a loop with a return side and supply side. The return side is usually larger than the smaller supply ducts. In a single home, you will have one or two large return ducts that extend the entire length of the house.

The supply side is the smaller side, and it supplies air to the house through the air vents. So if you look at your furnace and follow the furnace’s ends, you will have one large and another small duct.

For the air filter, it’s always before the HVAC equipment. The air always comes from the side of the duct with no HVAC components.

The blower fan, motor, evaporator coil, and other system parts are always downstream of the filter. And this makes sense as you need air filtered before it gets into the furnace.

You need to be observant.

It’s easy to install the filter backwards, even if you are experienced. All it takes is a loss of concentration, and you make a mistake. To avoid this, observe your actions. Also, consider hiring a furnace repair service Long Island to clean or replace the filter for you.

As mentioned above, the service providers don’t just do the basic work, they also tune up the appliance to ensure it’s in top working condition.

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