How To Replace The Furnace Filter (Step By Step Guide)

changing furnace filter

Where Is My Furnace Filter Located?

The filter will be on the return side of your furnace. Your air handler will have two sides you’re gonna have return ductwork on one side and you’re gonna have a supply on the other side.

If for some reason you can’t figure out which is your ductwork. One easy way to figure it out is to just turn on your heat for five to ten minutes let the furnace run.

And then come downstairs and feel your ductwork well put your hand on it whichever side is cold or basically room temperature that will be your return and the side that’s hot will be your supply.

So basically the air filter will always be in your return somewhere. Most of the time it’ll be placed right by the furnace either outside of the furnace or maybe inside the door.

But there are times where the filter is somewhere else as well maybe like in a ceiling or a wall. It doesn’t matter where the filter is located they work the same no matter where they are located.

How To Choose A Furnace Filter?

Choosing a furnace filter can be pretty troublesome because there are too many options available in the market. Most of the filters come ranging from 100-1900 MPR (microparticle performance rating).

The higher the MPR rating the better they filter dust, debris, bacteria, etc. Most of the commonly used furnace filters is a 300MPR filter that you can easily get from amazon or other stores.

If your furnace is overheating you should not use premium grade filters because they restrict the airflow and don’t filter that much. I personally use and recommend a medium-grade pleated filter (300MPR rating) which costs around $4-7.

How Often Should I Replace The Furnace Filter?

So most of the 1-inch filters will have a life cycle of 3 months. But they get worn down before that. You should replace your filter every month or two.

In most cases, you’ll be using your ac or furnace more than often so make sure you change it every month or two. That 3-months mark is for those who rarely use their ac or furnace.

Also if you have an electronic or washable filter then they should be cleaned every month or two depending upon your usage. Next, if you have a 4-inch pleated filter that should be replaced every half year (6 months).   

How To Replace Your Furnace Filter?

Follow the following steps below to change your filter. Make sure to take proper precautions so that you don’t hurt yourself.

Step 1: Turn Your Furnace Power Switch Off

furnace switch

The first thing you need to do is turn off the power to your furnace. A lot of times you’ll have a switch on the side of your furnace like a light switch just shut that off.

If you don’t have a switch you can also shut off the circuit breaker in the breaker panel for the electricity in your whole house. Or just go to your thermostat and set the cool and heat setting off and just set the fan to automatic.

Step 2: Remove Your Filter cover and Take Your Filter Out

furnace filter removing

Now just go on the side of your furnace and check where your filter is. If you don’t know where your filter is. One way to check is by removing the furnace door (both doors). After removing the doors you’ll be able to see your filter from inside. Now just remove the filter cover and take your filter out.

Step 3: Replace Your filter    

changing the furnace filter

Now you need to check your filter’s dimensions and replace it with the same size one. Now if you already have one and want to replace it. Just check for an arrow mark on the filter’s frame. It shows in which direction you should place it. So the direction arrowhead is pointing it should always face towards the blower motor. 

If you have different placements then it should be like this. So if the filter is on top of your furnace the arrow would be facing down towards the blower motor, if you have a filter in the ceiling the arrow will be pointing into the ceiling, if you have the filter on a wall behind a return grill the arrow will be facing into the wall. 

One more thing you should always write the date on the filter when you are replacing it. Filters do have a space on the frame where you can write stuff.

Why Do Furnace Filters Have A Net?

If you notice one side of the filter has a net, like a chicken wire net and the other one does not. Another reason for this is that sometimes you know if people neglect changing their filter.

The filter will start to get sucked in when it gets really restricted. The blower wheel can actually suck it in and it kind of wreaks havoc on the motor. So that’s why the net is there on the filter to prevent the filter from getting sucked in. 

Also, check our guide on ac repair: Troubleshooting most common problems.

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