What's the Difference Between MERV 8 and MERV 11 Furnace Filter Sizes?

If you're looking to improve your indoor air quality, upgrading your furnace filter is a great place to start. But, with so many options available, it can be hard to know which filter to choose. That's where MERV ratings come in.

Two of the most common MERV ratings are MERV 8 and MERV 11. But, what exactly do these numbers mean? In this article, we'll dive into the difference between MERV 8 and MERV 11 furnace filter sizes to help you make an informed decision for your home.

Get ready to breathe easy and learn all about the benefits of upgrading to a higher MERV rating. From superior air filtration to extended HVAC lifespan, you won't want to miss this informative guide.

1. What Is MERV and How Does It Affect Indoor Air Quality?

MERV stands for Minimum Efficiency Reporting Value and is the industry standard rating system for furnace filters. MERV values range from 1 to 16, with higher numbers indicating better filtration efficiency.

When a filter has a higher MERV rating, it can capture a greater percentage of airborne particles, including smaller ones that lower-rated filters can't catch. This means a higher MERV rating can lead to improved indoor air quality, which can benefit those with allergies, asthma, or respiratory issues.

However, it's important to note that a higher MERV rating doesn't always equate to better performance for every HVAC system. Filters with a high MERV rating can restrict airflow, which can cause strain on the system and potentially lead to damage if not addressed. It's crucial to consult with an HVAC professional to determine the appropriate MERV rating for your specific system.

In addition to MERV ratings, other factors to consider when selecting a furnace filter include filter material, size, and frequency of replacement. Proper maintenance and timely replacement of filters can go a long way in promoting healthy indoor air quality.

2. What Is the Difference Between MERV 8 and MERV 11 Filters?

MERV (Minimum Efficiency Reporting Value) is the rating system used to measure the effectiveness of air filters. The higher the MERV rating, the more particles the filter can capture. Both MERV 8 and MERV 11 filters are used in residential and commercial HVAC systems.

However, there is a difference in the number and size of particles each filter can capture. MERV 8 filters can capture particles as small as 3 microns, while MERV 11 filters can capture particles as small as 1 micron. This means that MERV 11 filters are better at capturing smaller particles like pollen, pet dander, and fine dust.

In addition to capturing a larger number of smaller particles, MERV 11 filters also have a higher resistance to airflow than MERV 8 filters. This means that the HVAC system must work harder to push air through the filter, which can lead to higher energy costs and decreased airflow.

To determine which filter is right for your needs, consider factors like the specific pollutants you want to remove, the size of your living space, and your budget. MERV 11 filters are generally recommended for those with allergies or asthma, but they may not be necessary for everyone. It's important to regularly replace your air filter according to the manufacturer's recommended schedule to ensure optimal indoor air quality.

3. Benefits of Using MERV 8 Filters

MERV 8 filters are a popular choice for many homeowners and HVAC professionals, and for good reason. Here are some benefits of using MERV 8 filters in your furnace:

1. Improved Indoor Air Quality (IAQ)

MERV 8 filters are designed to capture a wide range of contaminants and pollutants, including dust, pollen, pet dander, and larger particles. By removing these particles from your indoor air, you can enjoy cleaner, healthier air and reduce the risk of respiratory problems and allergies.

2. Protects Your HVAC System

When airborne particles are allowed to accumulate in your HVAC system, they can cause damage to the system's components and reduce its lifespan. MERV 8 filters help to prevent this damage by capturing these particles before they can enter the system.

3. Cost-Effective

MERV 8 filters are often more affordable than higher-rated filters, making them a cost-effective choice for homeowners who want to maintain good IAQ without breaking the bank.

4. Easy to Install and Replace

Unlike some other types of filters, MERV 8 filters are designed to be easy to install and replace. Most models can be replaced without the need for professional installation or special tools, making them a convenient choice for DIY enthusiasts.

Overall, MERV 8 filters offer a great balance of performance, affordability, and convenience, making them an excellent choice for many homeowners. If you're interested in improving your IAQ and protecting your HVAC system, consider upgrading to MERV 8 filters today.

4. Benefits of Using MERV 11 Filters

Upgrading from a MERV 8 to a MERV 11 filter can provide numerous benefits for your home's indoor air quality. Here are just a few:

1. Increased filtration efficiency: MERV 11 filters capture up to 95% of particles that are 3 microns in size or larger. This includes common allergens such as pollen, pet dander, and mold spores.

2. Better protection for your HVAC system: MERV 11 filters trap smaller particles before they can enter your HVAC system. This can help prevent damage to your system and extend its lifespan.

3. Improved respiratory health: By capturing more particles, MERV 11 filters can help improve indoor air quality and reduce respiratory irritation and allergen-induced asthma symptoms.

4. Reduced maintenance costs: MERV 11 filters require less frequent replacement than lower MERV-rated filters, saving you money in the long run.

Overall, upgrading to a MERV 11 filter can provide a noticeable improvement in your home's indoor air quality and help keep your family breathing easier. Always be sure to consult with an HVAC professional to determine the appropriate filter size for your system.

5. Which MERV Rating Is Right for Your Home?

When it comes to choosing the right MERV rating for your home, you should consider factors such as the location, the number of people in the home, any health concerns or allergies, and the presence of pets. For homes located in areas with high air pollution or near construction sites, a higher MERV rating may be necessary to capture fine particles and pollutants. Similarly, if anyone in the home suffers from allergies or respiratory issues, a higher MERV rating can help to remove allergens and other irritants from the air. If you have pets, a higher MERV rating is also recommended to capture pet dander and hair. However, keep in mind that higher MERV ratings may also restrict airflow and put more strain on your HVAC system, so it is important to consult with a professional before making any changes. Ultimately, the right MERV rating for your home will depend on your specific needs and preferences. Consider consulting with an HVAC professional to help determine the optimal MERV rating for your home and ensure that your HVAC system is properly installed and maintained.


In conclusion, the difference between MERV 8 and MERV 11 furnace filter sizes ultimately depends on your specific needs and household environment. If you have pets, allergies, or concerns about air quality, upgrading to a MERV 11 filter may be the better option for you. However, if you are on a budget and don't have any particular concerns, a MERV 8 filter will still provide adequate filtration. It's important to always check and follow your furnace manufacturer's recommended filter size and change intervals to ensure maximum efficiency and longevity of your furnace. With the right filter, you can keep the air in your home clean and healthy for you and your family.

Frequently Asked Question

It's important to know the size and type of furnace filter you need before replacing it. This is because different furnaces require different sizes of filters. Your brand of furnace may need an electrostatic or media filter of a particular size - so make sure to check your old filter for these details.

Replacing your filter regularly can save you money in the long run. It helps your HVAC system become more efficient, and also keeps the air quality high. So, what are the most common furnace filter sizes?

The most popular furnace filters come in the following dimensions: 10x20, 14x20, 16x24, 18x30, 12x12, 14x24, 16x25, 20x20, 12x20, 14x25, 18x18, 20x24, 12x24, 14x30, 18x20, 20x25, 12x30, 15x20, 18x24, 20x30, 12x36, 16x20, 18x25, 24x24 and 25x25. You can use your existing filter as a reference guide to find the perfect size for your furnace. The filter dimensions should be printed on its frame as length x width x height.

In conclusion, it's important to know your furnace filter size before you replace it. Doing so will improve your HVAC system's efficiency and save you money in the long run. Plus, a clean filter is key to keeping your air quality high.

When it comes to furnace filters, exact size matters. If you get a filter that is too small or too big, air will flow around it instead of through it, meaning not all of the air will be filtered. That's why it's essential to use the right size filter for your HVAC unit.

Here's what you need to know: the size of the air filter is typically listed in the big, bold font on the packaging, which is known as the nominal size. This is a rounded-up whole-number version of the actual size, which is written in the fine print on the filter's frame. That's usually 0.25'-0.5' smaller than the nominal size, and the actual measurements of the filter may vary slightly depending on the brand.

In some cases, less common sizes come true to size, meaning the nominal size is the same as the actual size. When that's the case, it's usually noted with “actual size” in parentheses on the filter's frame.

So, the verdict is in: the answer to the question 'Do furnace filters have to be exact size?' is a resounding yes! Be sure to get the right size air filter for your system to ensure it runs smoothly and that you reap all the benefits your filter has to offer.

Are you looking for the best furnace filter? Look no further! Our team of experts at This Old House Reviews have researched the top five furnace filters on Amazon to help you find the perfect one for your HVAC system. Plus, these products are available at local home centers or online retailers like Amazon.

A great furnace filter can make all the difference. It will keep your HVAC system running smoothly, potentially leading to lower electricity bills and better air quality. That's why we've taken the time to compile a list of the best furnace filters for you.

At the top of our list is the Filtrete furnace air filter. It promises to last up to three months and outperform filters made with fiberglass. Plus, it can capture 64% of airborne particles like pet dander and pollen. This filter also comes with instructions for easy installation on HVAC systems that require filters 20 by 25 by 1 inches in size.

Customers love this furnace filter. They find it easy to install, sturdy, and a great value. However, some customers have faced difficulties with Filtrete’s app.

When choosing a furnace filter, make sure to take into account its size, filtration level, and material. That way, you can get the best filter for your specific needs.

Changing or replacing your furnace filter is one of the best ways to maintain a healthy, efficient HVAC system. But you need to make sure that you're using the right filter for your system. Here's a step-by-step guide to help you pick the perfect one!

First, measure the dimensions of your existing filter. This will tell you the length, width, and depth you need. The easiest way to do this is to look at the existing filter and buy the same size.

Next, you need to choose the right MERV rating. The MERV scale ranges from 1-20 and measures the filter's effectiveness at catching particles in the air. The higher the value, the more effective the filter is at trapping particles, but it also means less airflow.

Now it's time to decide on the type of filter. There are many options available, so take some time to research the best type for your system.

Once you have everything you need, it's time to install the filter in your furnace/air handler slot. Remove the old filter to make room for the new one.

Finally, make sure to replace your filter regularly. If it clogs up with dust and particulate, it can reduce airflow and become ineffective.

Furnace air filters are essential for your heating system. You should replace your filter at least once every three months. So, how do you select the best furnace filter for your needs? Let us help you out!

Generally, furnace filters are made up of a cardboard frame, fiberglass filter, and metal mesh. These materials work together to strengthen the filter and protect your HVAC components from dust and debris. Plus, they also help improve the air quality in your home. Without a filter, your HVAC system could become dirty and its performance would suffer.

As air passes through the furnace filter, it traps and catches any contaminants. If you don't replace or clean your filter regularly, it can obstruct airflow and cause damage to your HVAC system. In most cases, you should change your furnace filters every three months. However, you may want to replace them more or less often depending on the situation.