Is a MERV Rated Air Filter Suitable for a Humidifier?

Do you struggle with allergies or asthma in your home? Your solution may be to use an air filter with your humidifier. However, not all air filters are created equal. One rating that may come to mind is MERV.

MERV stands for Minimum Efficiency Reporting Value, which measures the effectiveness of air filters. But the question is, is a MERV rated air filter the right choice for a humidifier?

In this article, we will explore what MERV ratings mean, the pros and cons of using a MERV rated air filter with a humidifier, and alternative options that may better suit your needs.

Understanding MERV Ratings

MERV (Minimum Efficiency Reporting Value) ratings are used to measure the effectiveness of air filters in residential and commercial HVAC systems. The rating system ranges from 1 to 20, with higher numbers indicating better filtration capabilities.

Filters with MERV ratings between 1 and 4 are considered standard, while those between 5 and 8 are better at capturing small particles such as pollen, dust mites, and pet dander. Filters with MERV ratings between 9 and 12 are high-efficiency filters that can capture tiny particles such as smoke, bacteria, and viruses.

Filters with MERV ratings between 13 and 20 are used in hospitals and other medical facilities to filter out the smallest particles, including microorganisms and tiny allergens. These filters use a combination of active carbon and electrostatic charge to capture contaminants and purify the air.

When choosing an air filter, it's important to choose one that is compatible with your HVAC system and that matches your indoor air quality needs. A higher-rated filter may not necessarily be better if it can't be accommodated by your system, and a lower-rated filter may not be sufficient if you have asthma or allergies or live in an area with high levels of pollution.

By understanding MERV ratings and choosing the right air filter, you can improve the quality of the air that you breathe and protect your family from harmful pollutants.

The Pros and Cons of Using a MERV Rated Air Filter with a Humidifier

Using a MERV rated air filter with a humidifier can have both advantages and disadvantages. Let's take a closer look at both.


1. Better Air Quality: MERV rated air filters are designed to capture small and large particles that can cause harm to your respiratory system. Using them in combination with a humidifier means you get better air quality overall.
2. Reduced Allergies: As mentioned, a MERV rated air filter can capture allergens that cause allergies. Using one with a humidifier is a great way to reduce allergies in your home.
3. Better Humidifier Performance: Using a MERV rated air filter with your humidifier can also enhance its overall performance. The filter can capture minerals from hard water that can cause problems for the humidifier. The filter can also prevent mold growth in the humidifier, which can be harmful to your health.


1. High Cost: MERV rated air filters are more expensive than standard filters. Using one with a humidifier can increase your overall cost of maintenance.
2. Reduced Humidifier Performance: MERV rated air filters are denser than standard filters, which can restrict air flow to the humidifier. This, in turn, can reduce the efficiency of the humidifier.
3. Regular Maintenance: Using a MERV rated air filter with a humidifier requires regular maintenance. That includes replacing the filter on a regular basis, and cleaning the humidifier regularly to prevent mold growth.

Overall, using a MERV rated air filter with a humidifier can be beneficial for your health and improve the air quality in your home. However, there are a few drawbacks to consider. Make sure to weigh the pros and cons before making a decision.

Alternatives to Consider for Humidifier Air Filters

While MERV rated air filters can work with humidifiers, there are also other alternatives that can improve the air quality in your home. Here are some options to consider:

HEPA Filters: HEPA filters have a higher filtration efficiency than MERV rated filters and can capture smaller particles, including bacteria and viruses. However, they do require more maintenance and replacement as they become clogged with more contaminants.

Activated Carbon Filters: Activated carbon filters are great for removing odors and VOCs (volatile organic compounds) from the air. They work by trapping the contaminants in the pores of the carbon filter, so they do not circulate back into the air.

Nanofiber Filters: Nanofiber filters are made up of fibers that are smaller than a human hair. These filters are excellent for capturing microscopic particles, such as pollen, dust, and mold spores, which can cause allergies and respiratory problems. Nanofiber filters are also washable and reusable, making them more cost-effective in the long run.

UV-C Light: Ultraviolet-c (UV-C) light is a technology that can kill bacteria and viruses by damaging their DNA. Adding a UV-C light to a humidifier can sterilize the water and prevent microbial growth in the humidifier tank.

Eco-Friendly Filters: Eco-friendly filters can be made of sustainable materials or are reusable, reducing the amount of waste that is generated. These filters are a great choice for those who want to reduce their carbon footprint and make environmentally conscious purchases.

By considering these alternatives, you can find the best air filter for your humidifier that meets your needs and preferences.

Maintenance and Replacement of Air Filters in a Humidifier

Just like any other appliance, your humidifier requires maintenance to continue functioning effectively. One aspect of maintenance is checking and replacing the air filter regularly. Here's a quick guide on how to properly maintain and replace your humidifier's air filter:

1. Check the Filter Frequently

Frequently check the air filter in your humidifier to see if it needs to be replaced. The frequency of replacements depends on the type of filter used, how often you use the humidifier, and the air quality in your home. A good rule of thumb is to check the filter monthly and replace it every three months.

2. Clean the Humidifier and Filter

Before replacing the filter, make sure to clean the humidifier thoroughly. Cleaning the humidifier and filter will improve its performance, extend its lifespan, and prevent the growth of bacteria and mold. Clean the humidifier according to the manufacturer's instructions. For the filter, gently clean it with a soft brush or cloth and warm water. Let it air dry completely before reinserting it into the humidifier.

3. Choose the Right Replacement Filter

Make sure you choose the right filter for your humidifier. Check the manufacturer's instructions to see the recommended filter type, size, and model number. Using the wrong filter type can affect the performance of your humidifier and may damage it.

4. Replace the Filter

Once you have the replacement filter, insert it into the humidifier according to the manufacturer's instructions. Make sure the filter is properly aligned and securely in place. Always use the filter frame when inserting the filter to prevent damaging it.

By following these simple steps, you can ensure that your humidifier's filter is always clean and functioning correctly. This will improve the air quality in your home and keep your humidifier running efficiently.

Overall Considerations for Choosing the Right Air Filter for Your Humidifier

When it comes to purchasing an air filter for your humidifier, there are a few key considerations to keep in mind. Here are some factors to consider:

1. Efficiency Rating

Make sure you choose an air filter with an appropriate efficiency rating for your specific needs. MERV ratings can give you some guidance, but other factors like the size of your home and the presence of allergens or other pollutants may also impact your decision.

2. Filter Type

Choose a filter type that is appropriate for your specific humidifier. Some filters may be better suited for certain models or types of humidifiers, so be sure to do your research before purchasing.

3. Replacement Schedule

Consider how frequently you will need to replace your air filter. Some filters need to be replaced monthly, while others may only need to be replaced every few months. Taking this into consideration can help you choose a filter that fits your maintenance schedule and budget.

4. Cost

While cost should not be the only factor you consider, it is important to keep in mind when shopping for an air filter for your humidifier. Some filters may be more expensive up front but offer longer lifespans, while other filters may be cheaper but require more frequent replacement.

5. Compatibility

Make sure the air filter you choose is compatible with your humidifier. Some brands or models may require specific filters, so be sure to double-check before making your purchase.

By considering these factors, you can choose the right air filter for your humidifier that fits your needs and budget, and ensures the cleanest possible air in your home.


In conclusion, it is not necessary to use a MERV rated air filter with a humidifier. While these filters are effective at capturing larger particles, they are not designed to handle the fine mist particles emitted by a humidifier. In fact, using a filter with a high MERV rating can actually reduce the efficiency of your humidifier and potentially create a breeding ground for harmful bacteria and mold.

Instead, it is recommended to regularly clean and maintain your humidifier to prevent the buildup of mineral deposits and mold. Using distilled water can also help reduce mineral buildup and improve the overall quality of the mist emitted by your humidifier.

By following these tips, you can ensure your humidifier is operating at its best and providing you with the healthy, comfortable air you need.

Frequently Asked Question

MERV stands for Minimum Efficiency Reporting Value - a scale created by ASHRAE to measure the effectiveness of filters in removing different sized particles. For example, a MERV-13 filter is designed to catch 90% of particles 3-10 µm in size, 85% of particles 1-3 µm in size (PM2.5), and 50% of particles 0.3-1 µm in size. Generally, filters with higher MERV ratings are better at catching higher percentages of particles, including the smaller ones.

When you install a filter in the airstream, it will create resistance. The amount of resistance depends on the type of filter material and the amount of area it covers. Standard fiberglass filters don’t generate much resistance, though it increases as the filter gets dirtier. To remove more pollutants from the air, you can use a filter with a different material such as a high MERV filter. These filters have smaller pores, which allow them to catch more pollutants, but also create higher resistance.

The problem with this is that the blower and furnace are only designed to handle a certain amount of pressure drop. Too much resistance means the air flow is low, making the heat exchanger get hotter and potentially crack. On the plus side, low air flow can result in better dehumidification in humid climates, as long as the air flow isn’t so low that it turns the condensate to ice.

So, the answer to the question is: yes, higher MERV filters are better, but you need to find the right balance between air flow, resistance, and effectiveness.

Air filters are designed to capture airborne particles, which can be anything from dust and pollen to mold spores and bacteria. The filter works by drawing air through itself and trapping the particles in the web of fibers that make up the filter.

What are the types of air filters

There are many different types of air filters available on the market. The type of filter you need will depend on the specific needs of your facility. Some common types of air filters include MERV, HEPA, activated carbon, and ultraviolet (UV) germicidal irradiation.

MERV: MERV stands for Minimum Efficiency Reporting Value. MERV ratings range from MERV-0 to MERV-16. The higher the MERV rating, the more efficient the filter is at capturing particles.

HEPA: HEPA filters are a type of air filter that is designed to capture very small particles. A true HEPA filter has a MERV rating of 17-20.

Activated carbon: Activated carbon filters are designed to remove gases and odors from the air.

UV germicidal irradiation: UV germicidal irradiation is a type of light that is used to kill bacteria and viruses.

There are pleated filters and panel filters. MERV 13 filters are pleated, while MERV 16 filters can be either pleated or panel. Pleated filters have more surface area because they are made up of multiple layers of filter media. The pleats create more space for the air to flow through, and the more layers of filter media there are, the more particles can be captured.

HEPA filters are usually pleated, but they can also be panel.

What are the differences between MERV 13 vs HEPA filters

While MERV 13 and HEPA filters both remove particles from the air, they work in different ways.

MERV 13 filters are designed to remove particles that are larger than 0.30 microns, while HEPA filters are designed to remove particles that are smaller than 0.30 microns. MERV 13 filters are often used in commercial and industrial settings, while HEPA filters are often used in hospitals and other medical settings.

MERV 13 filters are more efficient at removing large particles from the air, while HEPA filters are more efficient at removing small particles from the air. MERV 13 filters can remove up to 99.97% of particles from the air, while HEPA filters can remove up to 99.99% of particles from the air.

MERV 13 filters are less expensive than HEPA filters, and they can be used in a wider variety of settings. However, HEPA filters are more effective at removing small particles from the air, and they can be used in settings where MERV 13 filters cannot.

MERV and HEPA filters both work to capture airborne particles, but they do so in different ways. MERV 13 filters are designed to capture particles larger than 0.30 microns, while HEPA filters are designed to capture particles smaller than 0.30 microns. MERV 13 filters are more efficient at removing large particles from the air, while HEPA filters are better at capturing small particles. 

MERV 13 filters are less expensive and can be used in a wider variety of settings, but they can only remove up to 99.97% of particles from the air. On the other hand, HEPA filters are more expensive but can remove up to 99.99% of particles, making them ideal for medical settings. In short, MERV 13 filters are great for everyday use, while HEPA filters are better for specialized environments.

Your HVAC system includes a furnace, air conditioner, or heat pump. It's essential to keep these systems clean and efficient by regularly replacing the air filters. To do this, you'll need to know about MERV ratings.

The air filter in your HVAC system serves two key functions: it protects your system from dust, and it helps clean the air in your home. When the filter is clogged, dust can build up in the system, and the equipment may overheat and fail.

How often the air filter needs to be changed depends on your home's size, where you live, and if you have pets. Inspect it every month, and replace it when you can't see the filter material through the dust.

When choosing an air filter, refer to the specifications of your HVAC system to determine the size. The MERV scale is used to measure the filter's ability to remove particles from the air, and ratings range from 1 to 20, with lower ratings meaning lower-quality filters.

Remember to balance air cleaning with air flow when upgrading your filter to a higher MERV rating. Too dense of a filter can cause air flow restriction and harm your system. Ask your HVAC technician for advice when in doubt.

Replacing the air filter is easy. Open the blower compartment located between the air return and the furnace or air handler. Put the used filter in a plastic bag, then insert the new filter with the arrows pointing in the direction of the airflow.

MERV 11 filters used to be thought of as air flow restrictors, but this is no longer necessarily the case. Home Energy's 2009 experimental test concluded that the pressure drop of high-MERV filters isn't as severe as it used to be. If you're renting and don't have any special needs, then a standard, cheap fiberglass filter with a cardboard frame is fine to use every three months. But if you own your home, then it's worth investing in a more durable filter.

Pleated filters with more pleats per foot are the better option and should be more effective at improving indoor air quality. However, the price can be an issue. A standard 16x25x1 11 MERV filter will cost around $5, but you can save a bit if you buy them in packs of 12. Filtrete, Purolator, and Nordic Pure are all trusted brands.

If you plan to buy washable filters, be aware that cheaper models may have loose filter media after washing and won't perform as well. Disposable filters are also more hygienic since they remove all the dirt from the air. Keep in mind that the more pleats per foot, the better the filter will be.

So, when it comes to MERV 11, the issue of air flow restriction isn't as big as it used to be. With the right filter, you can improve your indoor air quality without having to worry about a pressure drop. Make sure to replace your filter every three months for the best performance.

MERV ratings are used to compare filters to determine which is most effective for eliminating pollutants in a home or office. The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) developed the Minimum Efficiency Reporting Value (MERV) system to measure how well an air filter captures common airborne particles. There are 16 MERV values, ranging from 1 to 16, and the efficiency increases with the MERV number.

Filters are tested against 12 size ranges of particles, with the smallest being around 0.3 microns and the largest around 10 microns. To give a sense of the size, a micron is one millionth of a meter and a strand of human hair is approximately 75 to 100 microns.

The MERV rating is determined by measuring the particle count upstream and downstream of the filter being tested over six intervals, beginning with a clean filter. Afterward, a special ASHRAE test dust is added for five additional measurement cycles. The filter’s performance is determined by calculating the particle density before and after passing through the filter, and then assigning a MERV rating.

The MERV 8 filter is the most common filter in the U.S. Understanding how MERV ratings work can help you understand why it's so popular and how to choose the most beneficial filter for your needs.