Changing Furnace Filters? The Homeowner's Guide To The Why, What, and How
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Changing Furnace Filters? The Homeowner’s Guide To The Why, What, and How

As a homeowner, to avoid frequent problems with your central heating and air conditioning system, it is vital to change your furnace filter on a regular basis. Although it may sound easy, changing a furnace filter can be challenging for some. This guide will explain the basics of furnace filters and how to change them. If you still find yourself struggling to change your furnace filter, don’t hesitate to ask a professional for help. After all, it is better to be safe than sorry when it comes to your home’s heating and cooling system. The team at Robert B. Payne is always happy to help out and ensure that your furnace is running smoothly. Contact us today!


What Are Furnace (Air) Filters?

Furnace filters are an essential part of any central heating and cooling system as they help to remove contaminants from the air that passes through the system. These contaminants can include dust and pollen.

Why Change Your Air Filters?

Prolong The Life of Your HVAC System

Your furnace filter plays an important role in keeping your HVAC system in good condition. It protects your furnace by trapping dust and other particles that could damage it. Over time, the filter can become clogged, which reduces the system’s efficiency and can cause it to overheat and break down. When you replace your air filter, you extend the life of your furnace and avoid costly repairs.

Maintain Healthy Air Quality

Another important reason to change your air filter is to maintain healthy indoor air quality. By trapping pollutants like dust, pet dander, and pollen, furnace filters help to improve the air quality in your home. This is especially important for children and people with allergies or respiratory problems like asthma.

Lower Energy Cost

Clogged air filters cause your HVAC system to work harder to circulate air, which can lead to higher energy bills. When you replace your furnace filter on a regular basis, you keep your system running efficiently and save as much as 15% on your energy bill.

How Often Should I Change my Furnace Filter?

The frequency with which you need to change your furnace filter depends on a number of factors, including the number of pets in your home, the size of your home, the number of people in your household, and whether or not anyone in your family has allergies. In general, it is recommended that you change your air filter every three months. However, if you have pets or live in a particularly dusty area, you may need to change it more often. If you have allergies or respiratory problems, you may need to change it more often as well.

What Kind of HVAC Equipment Requires Air Filter Change?

HVAC systems that regulate temperature by using hot and cool air, require regular filter changes. These systems are of two types: Forced Air Systems or Duct Systems: These systems use ductwork and vents to deliver conditioned air throughout the house. The most common type of forced air system is a furnace, which heats air and then blows it through the ductwork. Ductless Systems: These systems do not use ductwork. Instead, they have two separate units, the indoor unit, and the outdoor unit. The indoor unit delivers conditioned air directly into the room, while the outdoor unit removes heat from the room. A refrigerant line that passes through your wall connects both units. The mini-split is an example of a ductless system.

How to Change HVAC Filters

Forced Air Duct Systems

Now that you know the importance of furnace filters and how often you should be changing them, it’s time to learn how to actually change the filter. We’ll tell you where to find the air filter in a forced air duct system, how to buy the right size of a replacement filter, and then how to do the replacement on your own.

Where to Find The HVAC Filter

We are aware that most new homeowners are not familiar with the location of the furnace filter. In order to help you out, we have compiled a list of the most common places where homeowners find their filters. The majority of residential HVAC forced air systems have an outside unit and an inside unit. This means that they are split systems. In these systems, you’ll find the air filter inside the HVAC system or in the air duct system. This depends on the airflow configuration.

Upflow Configuration

For upflow configuration, your indoor HVAC unit is placed on the lowest floor in your home and the air is sent upward through the ductwork and into your rooms. You’ll find the filter placed in any of three places.

  • The filter is placed in the return air grill – this is the metal grate that covers the opening in your wall or ceiling where air enters the HVAC unit. You’ll need to remove the screws or hinges that hold the grill in place in order to access the filter.
  • The filter is at the return duct, which is the large metal duct that carries air from your rooms back to the furnace. The filter is also usually placed at the air handler, which you’ll find on the lowest floor in your home.
  • The filter is located within the air handler or furnace. You’ll have to take out the access panel to reach the air filter.
  • Downflow Configuration

    Your HVAC system is a downflow system if your furnace is located on an upper floor in your home (usually the attic or on the middle floor) and the air is sent downward through the ductwork into your rooms. The majority of filters are placed in one of three places in a downflow configuration.

  • The filter is at the air handler or the return duct, which is located outside the furnace.
  • The filter is located within the furnace. You’ll have to take out the access panel to reach the air filter.
  • The filter is placed in the return grill, whose location has already been described.
  • Horizontal Configuration

    If you have a horizontal configuration, this means that your furnace is located on its side and not standing up vertically. It takes in cool air from one side and then moves out warm air through the other side. The horizontal configuration also has three potential places for the air filter.

  • The filter is placed in the return duct, which is located on one side of the furnace.
  • The filter is located within the air handler or furnace itself, and you’ll have to take out the access panel to reach it.
  • The filter is at the return grill, just as in the other configurations.
  • How to Tell The Size of Your HVAC Air Filter

    Most big box stores have a range of air filters. The problem is that most homeowners don’t know what filter they need for their HVAC system. The first step is to determine the size of filter you need for your AC or furnace. Your furnace filter works best if it fits correctly.

    Is Your Furnace Filter Too Small or Too Big?

    An air filter that’s too big won’t fit properly, and one that’s too small won’t catch all the contaminants in the air. Your air filter should be flush with the sides of the housing unit and the top of the air duct. A good way to determine the size you need is to get it from your current filter if it’s a perfect fit. The size of the air filter is often inscribed on its frame’s edge. The actual size is written in small numbers like 15.75×19.75×0.75. The nominal size is written in bold and rounded numbers like 20x25x1. The nominal size is the one you use to order a new filter. If the old air filter is not a good fit or you don’t have it, you’ll need to measure your air ducts. Measure the return air duct depth in inches as well as the height and width of the opening where your air filter slots in. Once you have these dimensions, round up to the nearest whole number. This is the nominal size you’ll use to order a new filter.

    Where to Buy Furnace Air Filters

    In-Store Purchase

    If your air filter size is common, you’ll be able to find it at most hardware or big box stores. However, if you have an older home or an uncommon furnace, you might have to head to a filter specialty store where you’ll place a custom order.

    Air Filter Subscription

    With an air filter subscription, you don’t have to worry about running out of filters or remembering to buy them. They’ll be delivered right to your door when you need them. This can be a great option for busy families or those who want the convenience of never having to think about changing their furnace filter again. Robert B. Payne delivers top-quality filters right to your doorstep so you can be sure your furnace is always running at peak efficiency.

    Determining The MERV Rating

    The MERV (minimum efficiency reporting value) rating is a number between 1 and 20 that’s assigned to an air filter. This number corresponds to the size of particles that the filter can remove from the air. This scale was introduced by ASHRAE in the 1980s. The higher the MERV rating, the smaller the particle that will be trapped by the filter. But this also means less airflow and more stress on your HVAC unit. To overcome this problem, as you increase the MERV rating, you should also increase the filter’s thickness. A 4″ filter should be a good pick. A filter with a MERV 2 rating is designed to trap 20% of particles. These are the bigger particles like mold spores, pollen, and dust. You’ll find the MERV rating printed on the side of the filter’s frame. If it’s not there, you probably have a MERV 2 filter. This is the lowest level available. A MERV 8 air filter will remove 70% of the particles in the air. A MERV 11 filter is great as it traps 85% of particles, including smoke and particles that cause allergies. At the other end of the spectrum, a MERV 16 filter is designed to trap 95% of particles like dust, smoke, lint, pollen, bacteria, viruses, and more.

    How to Change a Furnace Filter

    Now that you know the importance of changing your furnace filter, it’s time to learn how to do it. Follow these steps, and you’ll have it done in no time.

    • Don’t forget to always wear gloves and a dust mask when handling or changing your furnace filter.
    • First, turn off your furnace. This will prevent any accidents from happening while you’re working.
    • Then, locate and remove your old furnace filter.
    • If you have a washable furnace filter, clean it off with soap and water or according to the instructions provided by the manufacturer. Let it dry completely before putting it back in. If you have a disposable furnace filter, which is the most typical type, dispose of it safely.
    • Because your old air filter may contain mold, bacteria, and other harmful particles, it’s essential to dispose of it carefully. To do this, put the old filter in a plastic bag and tie it up tightly. Then, throw it away in your regular trash can. Never leave it lying around in your home.
    • Now that you have removed the old furnace filter, it’s time to install the new or washed one. Make sure it’s facing the correct way (check the arrow on the frame). It should point in the direction of the blower.
    • Seal the edges of the filter with silver tape or a magnetic cover to ensure a snug fit. Never use duct tape. Finally, turn on your furnace and check that the airflow is not restricted. You’re all done! Now you know how to change your furnace filter like a pro.

    Do You Need Help Replacing Your Furnace Filter?

    If you’re unsure which furnace filter is right for your home, call us at 540-373-5876. We can help you find the perfect filter for your needs and budget. Whether you’re looking for a MERV 8 air filter or something with a higher rating, we can help. We also offer air filter subscriptions, so you never have to worry about changing your furnace filter again. Robert B. Payne delivers top-quality filters to your doorstep so you can be sure your furnace is always working efficiently.

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