Your furnace is a large investment. With this in mind, you want it to last a long time so that you can get your money’s worth from the purchase. One of the best ways to accomplish this is by making sure your furnace is properly taken care of. This means maintenance 1-2 times per year and regularly changing the filter.
You want to make sure you choose the best air filter for your home furnace. The filter you choose can affect all sorts of HVAC aspects. This includes air quality, furnace lifespan, and even the number of repairs you may need over time. To help you choose the right one, Meade has compiled this guide to furnace air filters. Check out this useful information below.
What Is a Furnace Air Filter?
A furnace air filter is a device that helps remove dust, dirt, and other debris from the air. The air circulating through your home passes through the filter to be cleaned. This helps your furnace continue to run properly as there is less debris to cover or damage the more sensitive components of your furnace. It also provides cleaner air for your family to breathe.
A furnace air filter is composed of tiny fibers that block larger pieces of debris as they pass through. The smaller the gaps, the smaller the debris the filter can catch. However, smaller gaps can also cause your furnace to work harder. Therefore, it is important that you choose the best filter for your home furnace.
Types of Air Filters
One of the first aspects to know about furnace air filters is that there are different types. This includes pleated air filters, non-pleated air filters, and HEPA air filters. Each one has its own pros and cons. Read the information below to help determine which type is best for your furnace and home. You can also talk to a B&L Ott professional for more information.
Non-Pleated Air Filters
Non-pleated air filters are pretty standard and are generally the cheapest type of filter. They are typically a flat sheet of fibers. However, sometimes they are reinforced with other materials.
This category includes fiberglass, electronic, and electrostatic air filters.
Non-pleated air filters are commonly known as “throwaway” filters because they do not last very long. They usually last about 1 month before they will need to be replaced. Non-pleated filters often come with new furnaces. They come in a variety of sizes so you can also find one to fit almost any type and model of furnace.
Generally, non-pleated filters will block enough of the large particles to keep your furnace running properly. However, if you are looking to clean the air in your home, this type of filter is not very effective. They can trap large debris particles such as hairs, dust, and fur. However, they are not able to catch smaller particles such as bacteria and viruses. They do allow for good airflow, though, which can promote efficiency.
Pleated Air Filters
Pleated air filters take the sheet of fibers that the non-pleated filters have, but add zig-zag folds like a fan. This increases the surface area and allows the filter to catch more of the debris passing through.
Pleated filters are a bit more expensive than non-pleated filters, but are also more effective at cleaning the debris from the air. They can stop debris, including dust mites, dust, pollen, mold, pet dander, and even the smallest bacteria. If anyone in your family suffers from allergies or respiratory issues, a pleated air filter will be more than worth the extra price to keep your family from suffering symptoms.
Like the non-pleated filters, they also come in a variety of sizes so it should be fairly easy to find one for your particular HVAC system. You can find thicknesses of anything from 1” to 6”. They last a bit longer than the non-pleated filters, but it is still important to change the filter regularly to keep the air clean and your furnace running efficiently.
HEPA Air Filters
HEPA stands for high-efficiency particulate air and sets a standard for filters with the HEPA label. They are generally thick filters and filter 99.97% particles whose diameter is equal to 0.3 μm. This includes hairs, mold, dust, pet dander, asbestos, pollen, bacteria, and more. You can also invest in better models that can stop even smaller particles.
HEPA filters generally cost more than non-pleated and pleated air filters. It is also worth noting that they can vary in price depending on multiple variables. These variables include efficiency, brand, type, and more.
They are typically made of fiberglass or plastic. HEPA filters are generally thick as well. This thickness helps them catch more particles than the average filter. While particles can manage to sneak through part of the filter, they are generally too heavy and don’t move fast enough to make it all the way through. Additionally, if the particles are still too small, the zig-zag pattern they tend to travel in also ends up getting them stuck in the filter.
Furnace Air Filter Sizes
The filter size you need is determined by the make and model of the furnace you have. Below are some of the most common sizes of filters.
| 12 Inches | 14 Inches | 16 Inches | 18 Inches | 20 Inches | 24 Inches |
| 12 x 12 x 1 | 14 x 14 x 1 | 16 x 16 x 1 | 18 x 18 x 1 | 20 x 20 x 1 | 24 x 24 x 1 |
| 12 x 20 x 1 | 14 x 20 x 1 | 16 x 20 x 1 | 18 x 20 x 1 | 20 x 20 x 4 | 24 x 30 x 1 |
| 12 x 24 x 1 | 14 x 24 x 1 | 16 x 25 x 1 | 18 x 24 x 1 | 20 x 24 x 1 | |
| 12 x 30 x 1 | 14 x 25 x 1 | 16 x 25 x 4 | 18 x 30 x 1 | 20 x 25 x 1 | |
| 12 x 36 x 1 | 14 x 30 x 1 | 16 x 30 x 1 | 20 x 25 x 4 | ||
| 20 x 30 x 1 |
How Often Should You Change Your Air Filter?
How often you need to change your furnace air filter depends on a variety of aspects. This includes what type of filter you have, how much dirt your family track in, and if you have pets. If you have a high-quality filter, you may not need to change it as often. On the other hand, if you have a lot of dirt in your home or furry friends, you may want to change it more often.
As a rule of thumb, a standard filter should be changed every 30 days. However, some better quality filters can last a bit longer. You should check these types of filters about every 90 days. No matter what type you have, it is good to be cautious and at least check your filter every 30 days. When the filter is grey and covered in a layer of dust, it is time to change or clean it.
Making Sure Your Filter Is the Right Fit
When it comes to ensuring that your HVAC system runs at peak efficiency, it is important to ensure that you get the right size filter. If the filter doesn’t fit properly, dirt can pass through the gaps. If this dirt gets to the more sensitive components in your furnace and can cause issues. If left long enough, it can turn into a major and costly repair.
Most filters are 1” deep, however, some can be deeper. Be sure to take height, length, and depth measurements before you head to the store or place your order online. It is also a good idea to watch out for cheaper or damaged filters. You may also have trouble getting these to fit properly. As mentioned above, it is important to your furnace’s health that your filter fits properly.
Furnace Air Filter Location
The filter may be located in different places depending on your specific HVAC system. However, there are some common places you can look. These include:
- The blower compartment on your furnace. This is a door on the bottom.
- A sliding door on your air handler.
- A V shape on the upper blower compartment.
- A slide-in furnace rack on the side of the furnace.
- Behind the return air ducts in your home. There could be a filter behind each one.
Generally, it is somewhere near your furnace or behind your return air ducts. If you need help locating your furnace, it is usually in the basement, attic, garage, utility closet, or crawlspace. If you require any more assistance or need help figuring out how to install an air filter in a furnace, call on the professionals at Meade.
MERV Ratings
MERV stands for minimum efficiency reporting value. It is a rating system used to measure how effective filters are at removing pollutants from the air. Every filter is rated with a number 1-20. The higher the number, the smaller the particles the filter can trap. However, it is worth noting that 20 ratings are generally used for clean rooms in hospitals. This is likely not a rating you will require in your home or business. A MERV rating between 8-13 is usually sufficient for an average household.
MERV Filter Ratings and Efficiency
One might assume that the higher MERV rating is better simply because it can remove more of the particles polluting the air in your home. However, this is not the case. While it is great to have cleaner air, filters with higher MERV ratings also block more of the air. If your furnace was not designed to work with this much resistance, you can experience issues with efficiency. You may notice your utility bills rise or even less comfort in your home.
MERV Filter Ratings and Air Quality
There has been debate over the years as to whether particle filtration actually has health benefits. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) researched this claim. They found that it is “modestly effective” for those suffering from allergies and respiratory conditions. It can lower the concentration of infectious airborne particles, thereby “substantially decrease the portion of disease transmission caused by these small particles.”
MERV Rating Chart
Below you will find a chart with different MERV ratings, the particle size they filter down to in microns, common applications, and some of the contaminants a filter of this MERV rating removes.
| Application | Contaminants Removed | |
| MERV 1-4
10.0 microns |
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| MERV 5-8
3.0-10.0 microns |
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| MERV 9-12
1.0-3.0 microns |
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| MERV 13-16
0.3-1.0 microns |
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| MERV 17-20
Less than 0.3 microns |
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By taking the time to make sure you get the right filter, you can help ensure that your furnace works properly and lasts long. If you need any help or have any questions, you can call on the professionals at Meade. We are happy to help you with all of your HVAC and air quality needs.
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