How to Install an Air Filter in a Furnace

A question I’m often asked by people when visiting friends or vacationing in another state is how to install an air filter in the furnace. It’s easy, you just have to know the process and you’ll have it in no time. The way I understand it is this: When you turn on your furnace (indoor or outdoor), the air passes through a filter unit called the blower. Once the air passes through the filter, it is vacuumed by a machine called the collector. When the air leaves the collector, it goes into the room where the furnace is.

So, in order for us to understand how to install air filter in the furnace, we need to know how air passes through the blower and into the room where we want to heat. That’s a pretty basic explanation but let me elaborate. Think of the blower as a big fan that sucks up air and then blows it back out into the room. That’s the way air passes through a filter.

Now, a furnace starts with a closed blower, meaning that it creates air from a vacuum that is open. When you put in the air into the furnace, the air passes through the closed blower. Now, imagine a large fan that is blowing air across this pathway continually (like blowing air out of a window).

That’s how air is moved into the room where we want to heat. We can measure the amount of air that flows through the blower by attaching a reading device to the blower. The reading will tell you how much air is passed through the blower. You also may not see any condensation on the reading device, as this is usually caused by the moisture in the air binding to the inner portion of the blower. That part will eventually loosen and allow the water to escape. This is called air removal and is how your home keeps dry.

So, what is happening when you have your air filtered? When you turn on your furnace, the blower (the part that carries the dirty air) starts up and starts blowing into the room. That air is now going through the filter. Over time, that filter will become clogged with dirt and debris and will need to be replaced.

So, how to install an air filter in the furnace is to do it the old fashioned way. It is a lot harder than today’s technology and even harder than back in the old days (when it was invented). Back then, there were air filters that came on the top of the furnace. They were made from metal, but they were so cumbersome they were never installed properly.

If you want to avoid that type of problem, you should get an air filter that comes with the duct system. You can put that air filter inside the furnace or you can place it on the blower. Either way, you will feel better because you will not have to lug around the extra weight of the filter. But, that does not mean you cannot install it; just not in the way most people do. Now, there are new systems that do not require you to go through any type of messy installation.

So, if you are wondering how to install air filters in the furnace, the correct way is the way that has been handed down through the years. Get the filter that is designed for the blower. It does make sense when you think about it. After all, if that device is not doing its job correctly, then you would not want to waste your time or money on it.