Furnace Filters 101: Understanding Types, Choosing the Right One, and Proper Maintenance
The Importance of Furnace Filters for Your HVAC System
as a homeowner, it’s important to understand the role that furnace filters play in keeping your HVAC system running smoothly. These filters act as a barrier, trapping large particles such as dust and debris, preventing them from entering the furnace and potentially causing damage. A dirty filter can reduce the efficiency of the HVAC system, increase energy consumption, and even cause damage to the equipment. That’s why it’s essential to choose the right type of filter for your furnace and HVAC system and to replace it regularly to ensure the system is running at its best.
Think of your furnace filter as the first line of defence for your furnace; it’s not there to purify the air in your home but to protect your furnace from damage. So, don’t neglect this important aspect of home maintenance. It will benefit your HVAC system, your energy consumption, and your wallet in the long run.
Understanding the MERV rating
MERV stands for Minimum Efficiency Reporting Value. It is a standard measurement of the effectiveness of air filters in removing particles from the air. It ranges from MERV 1 to MERV 20, with higher MERV values indicating a higher level of filtration. MERV ratings are based on the ability of a filter to remove particles of a specific size range from the air. MERV 1-4 filters are considered to be “pre-filters,” MERV 5-8 filters are “general purpose filters,” MERV 9-12 filters are “high-efficiency filters,” and MERV 13-16 filters are “very high-efficiency filters.” MERV 17-20 are typically used in specialized applications like clean rooms and hospitals.
Understanding the Different Types of Furnace Filters
When it comes to furnace filters, you have a few options to choose from. The most common furnace filters are fibreglass, pleated, and HEPA (High-efficiency Particulate Air) filters. It’s important to select the right one for your home and HVAC system based on factors such as the MERV rating, airflow restriction, and the specific needs of your home.
It’s important to remember that a furnace filter is not there to purify the air in your home but to protect your furnace from damage. So choose the right one for your specific needs and budget, and don’t forget to check the compatibility of the filter with your furnace and HVAC system, considering the MERV rating and airflow restriction.
Types of Furnace Filters
1-inch Fibreglass Filters
If you have a one-inch filter slot, fibreglass filters are an excellent choice for those looking for an affordable and effective option for furnace filters. These filters are specifically designed to capture large particles, such as dust and debris, which can cause damage to the furnace and HVAC system over time. They are also less restrictive on airflow, which helps maintain your HVAC system’s efficiency.
While they may not capture as many small particles as other types of filters, they are still an excellent option for maintaining the basic level of air quality in your home. They are especially great for homes with minimal dust and debris and are easy to find and install. They are a cost-effective option that can be found at most home improvement stores.
Fibreglass filters are not the best option for homes with pets, allergies or asthma, as they may not be able to capture small particles effectively. However, they are still an excellent option for maintaining the basic level of air quality in your home. It is recommended to check and replace these filters once a month or as per your furnace manufacturer’s recommendation to keep your HVAC system running efficiently.
The downside of fibreglass filters is that they need to be changed more regularly – typically once per month. Also, if you have pets or allergies, read on.
A fibreglass mesh furnace filter, made of interwoven fibres, is used to capture dust and other particles in the air.
1-inch Pleated Filters
Consider a pleated filter if you’re looking for a more efficient option for capturing a wider range of particles and pollutants from the air. These filters are made of a thicker and denser material, creating more surface area for particles to trap. This makes them better at capturing small particles such as pollen and pet dander. They have a higher MERV rating, meaning they can capture more particles and pollutants, making them more efficient than fibreglass filters.
But remember that these filters can restrict airflow more than fibreglass filters, which can stress your HVAC system and decrease efficiency. They are more expensive than fibreglass filters but have a longer lifespan. These filters are a better option for homes with pets or allergies, as they can effectively capture small particles that trigger asthma or allergies.
When choosing pleated filters, select the right one for your HVAC system by matching the filter’s size and MERV rating to your system. This will ensure optimal performance and efficiency of your HVAC system. For most systems, we recommend a maximum MERV rating of 8. Remember to check and replace these filters as per the manufacturer’s recommendation or at least every 3 to 6 months to keep your HVAC system running at its best.
A close-up image of a pleated furnace filter designed to improve indoor air quality by trapping dust, dirt, and other particles in HVAC systems.
4 to 5-inch Pleated Filters
A larger filter slot in your furnace, such as four or five inches, allows you to use larger pleated filters. These filters have a larger surface area due to the pleats, which enables them to provide a higher level of filtration while still allowing for good airflow. This is because the large pleats increase the filter media available to capture pollutants while allowing enough air to pass through the filter without restricting airflow. Additionally, larger filters tend to last longer, reducing the need for frequent filter changes. Overall, larger pleated filters are a great option for those with larger filter slots in their furnace, as they can effectively remove more pollutants from the air while maintaining good airflow. We still recommend keeping the larger pleated filters to a MERV 8 minimum.
HEPA Filters
HEPA filters, also known as high-efficiency particulate air filters, are considered one of the most efficient types of furnace filters. However, they are also one of the most restrictive options in terms of airflow, putting a lot of stress on the HVAC system and potentially decreasing its efficiency. They are also the most expensive option and may require professional installation.
While they can capture a wide range of particles and pollutants, including small particles such as pollen, pet dander, and even some bacteria and viruses, and have a very high MERV rating, they may not be the best option for everyone. They are best suited for homes with severe allergies, asthma, or other respiratory issues, as well as for homes with pets, as they can effectively capture small particles that can trigger allergies or asthma.
Keep in mind that even though they are considered one of the most efficient types of furnace filters, they are not suitable for every household. Check and replace these filters as per the manufacturer’s recommendation or at least every 3 to 6 months to ensure the HVAC system continues to function at its optimal level.
Factors to Consider when Choosing a Furnace Filter
Merv Rating
When choosing a furnace filter, one of the most important factors to consider is the Minimum Efficiency Reporting Value (MERV) rating. This rating measures a filter’s ability to capture particles and pollutants of different sizes. The higher the MERV rating, the more efficiently the filter captures particles and pollutants.
It’s important to note that filters with higher MERV ratings can have a greater restriction on airflow, which can put more stress on the HVAC system and potentially decrease its efficiency. It’s also important to consider the specific needs of your home, such as whether you have pets, allergies or asthma, and the level of air pollution in your area.
Choose a filter with the appropriate MERV rating that matches your needs and your HVAC system’s capabilities. It’s recommended to consult with a professional or refer to the manufacturer’s recommendations to ensure that you choose the right filter for your HVAC system.
Airflow restriction
When choosing a furnace filter, consider the level of restriction on the airflow that the filter may create. Some filters, such as pleated and HEPA filters, can create more airflow restriction, which can stress the HVAC system and potentially decrease efficiency. This restriction can also affect the overall performance of the HVAC system.
Consider the overall performance of your HVAC system, the specific needs of your home and the compatibility of the filter with your furnace and HVAC system. If you have an older or less efficient HVAC system, it may not be able to handle the added restriction on airflow caused by certain types of filters. On the other hand, a newer or high-end HVAC system may be able to handle a filter that creates more restriction on airflow and still maintain its efficiency.
Consult with a professional or refer to the manufacturer’s recommendations to ensure that you choose a filter suitable for your specific HVAC system and won’t affect the airflow restriction too much.
Specific Needs of Your Home
When choosing a furnace filter, consider the specific needs of your home. Factors such as whether you have pets, allergies or asthma, and the level of air pollution in your area can all impact the type of filter you should choose.
If you have pets, for example, you may want to consider a filter with a higher MERV rating that can effectively capture pet dander and other small particles. If you or a family member has allergies or asthma, you may also want to consider a filter with a higher MERV rating that can capture pollen and other allergens.
It’s also important to consider the level of air pollution in your area and how that might affect the type of filter you choose. In areas with high levels of air pollution, you may want to consider a filter with a higher MERV rating that can capture a wide range of particles and pollutants.
By considering the specific needs of your home, you can ensure that you choose a filter that effectively captures the most relevant particles and pollutants to your home and your family’s health.
Filter Size
Another essential factor to consider when choosing a furnace filter is the size. Choosing the right size filter for your furnace or HVAC system is crucial, as a filter that is too small or too big can decrease the system’s efficiency. A filter that is too small will not be able to capture enough particles and pollutants, while a filter that is too big can restrict airflow and put unnecessary stress on the system.
It’s important to refer to the manufacturer’s recommendations or consult with a professional to determine the correct size filter for your specific furnace or HVAC system. A filter that is not the correct size can also cause the filter not to seal correctly and allow unfiltered air to pass through.
When buying a filter, you’ll need to know the size of your current filter and the size of your furnace or HVAC unit. It’s also important to check the filter’s size before installing it to ensure that it fits properly and will work as intended.
Compatibility with Your Furnace and HVAC System
When choosing a furnace filter, it’s essential to ensure that it is compatible with your furnace and HVAC system. Not all filters are suitable for all types of HVAC systems, and using the wrong type of filter can cause damage to the system or decrease its efficiency.
It’s important to check the manufacturer’s recommendations or consult a professional to ensure that you choose a filter compatible with your specific HVAC system. The compatibility includes the size, the MERV rating, and the airflow restriction. A filter that is not the correct size can also cause the filter not to seal properly and allow unfiltered air to pass through.
It’s also important to consider the age and condition of your HVAC system when choosing a filter. An older or less efficient HVAC system may not be able to handle a filter that creates a high restriction on airflow or have a high MERV rating.
By ensuring compatibility between your furnace filter and HVAC system, you can ensure that your HVAC system runs efficiently, effectively, and for a longer period.
Importance of regular filter replacement
Effects of a Dirty Filter on HVAC Efficiency
A dirty furnace filter can have a significant impact on the efficiency and performance of your HVAC system. As a filter becomes clogged with dust, dirt, and other particles, it can restrict airflow, making it harder for your HVAC system to circulate air throughout your home. This can cause your system to work harder and longer to maintain the desired temperature, leading to higher energy costs and increased wear and tear on your HVAC system.
A dirty filter can also lead to poor indoor air quality as pollutants, dust, and other particles are not captured by the filter and can circulate through your home. This can exacerbate allergies and asthma symptoms and lead to other health issues.
Regularly check and replace your furnace filter to ensure it’s clean and functioning correctly. Doing so can help maintain the efficiency and performance of your HVAC system and ensure that the air in your home is clean and healthy.
Recommended Replacement Schedule
It’s important to have a regular replacement schedule for your furnace filter to ensure that it is always functioning at its best and your HVAC system is running efficiently. The recommended replacement schedule for your filter will depend on a few factors, such as the type of filter you have, the level of air pollution in your area, and the specific needs of your home.
For example, disposable fibreglass filters should be replaced every 1-3 months, whereas pleated filters can last up to 6 months. HEPA filters can last up to 12 months. However, if you have pets or someone in your home who suffers from allergies or asthma, you may need to replace your filter more frequently.
Check the manufacturer’s recommendations for a replacement schedule or consult a professional to determine the correct replacement schedule for your filter. Additionally, it’s also important to regularly inspect your filter and replace it as needed, even if it’s before the recommended replacement schedule.
By following a recommended replacement schedule and regularly inspecting your filter, you can ensure that your HVAC system is running efficiently and effectively, and you can maintain the overall air quality in your home.
Alternatives and Supplements to Traditional Filters
Electrostatic Air Filters
One of the alternative options to traditional furnace filters is the use of electrostatic filters. These filters use an electrical charge to attract and capture particles in the air, making them highly efficient in trapping small particles such as pollen, dust, and pet dander. Additionally, since these filters do not require frequent replacement like traditional filters, they can save you money in the long run.
However, there are a few drawbacks to using electrostatic filters. The main one is that they need to be cleaned regularly to maintain their effectiveness. This task can be a bit cumbersome for some homeowners, and if not done correctly, it could decrease the filter’s performance. Additionally, some electrostatic filters can be pretty expensive to purchase and install. Furthermore, these filters can restrict airflow to a certain extent, which may cause your HVAC system to work harder and reduce efficiency.
When considering electrostatic filters, it’s essential to consider the regular maintenance required, the cost, and the potential airflow restriction. It’s also worth noting that many reputable brands offer electrostatic filters, so do your research to find one that is the best fit for your home and your specific needs.
An electrostatic air filter, which uses static electricity to attract and capture particles in the air.
A close-up image of an electrostatic air filter which uses an electrostatic charge to trap and filter pollutants in HVAC systems.
Electronic Air Filters
Electronic air filters, also known as electrostatic precipitators, use an electronic charge to capture particles and pollutants in the air. They generate an electrostatic charge that attracts and captures particles such as dust, pollen, and pet dander. These filters can be more effective at capturing smaller particles than traditional filters and have a longer lifespan.
One of the benefits of using electronic air filters is that they are low-maintenance and can be washed and reused, saving money in the long run. Additionally, they can be easily removed and cleaned, which makes it easy to maintain the efficiency and performance of the system.
Electronic air filters require more maintenance than traditional filters and must be cleaned regularly. Ensure that the electronic air filter is compatible with your HVAC system and follow the manufacturer’s recommendations for maintenance and replacement.
In addition to their effectiveness and maintenance, the cost is also essential when choosing an electronic air filter. These filters are more expensive than traditional filters, both in terms of the initial purchase and maintenance costs. Additionally, the cost of electricity to run the electronic charge may also be a factor to consider. However, weigh the cost against the benefits and consult a professional to determine whether an electronic air filter is a cost-effective solution for your home.
An electronic air cleaner which uses ionization and electrostatic attraction to remove particles from the air.
UV Light Purifiers
UV light air purifiers are an excellent option for those looking to improve the air quality in their home and reduce the growth of mould, bacteria and viruses. They work by emitting ultraviolet radiation and neutralizing allergens, viruses and bacteria in the air. This makes them an excellent option for people with allergies or asthma. UV light air purifiers are also commonly used in hospitals and other healthcare settings as they can help to prevent the spread of infectious diseases.
UV light air purifiers are not used as furnace filters but as a supplement to traditional furnace filtration systems. They are placed in the ductwork near the furnace to improve the air quality. If air quality is your primary concern, it’s worth noting that UV light air purifiers should be used in conjunction with other air-cleaning methods, such as HEPA filters or electronic air purifiers, to achieve optimal results and ensure that your home’s air is clean, fresh and healthy to breathe.
A UV air purifier which uses ultraviolet light to kill bacteria and viruses in the air.
Other Air-purifying Devices
Air-purifying devices are electronic devices designed to improve indoor air quality by removing pollutants, allergens, and other particles from the air. Some common types of air-purifying devices include:
- HEPA air purifiers: These devices use a HEPA filter to capture particles as small as 0.3 microns, including dust, pollen, pet dander, and even some bacteria and viruses. They are highly efficient and can improve indoor air quality.
- Electronic air purifiers: These devices, also known as ionizers, work by releasing negatively charged ions into the air, which attach to positively charged pollutants, allergens, and other particles, making them heavier and causing them to fall to the ground or be trapped in a filter.
- Activated carbon air purifiers: These devices use activated carbon to absorb pollutants and odours from the air.
- Ozone generators: These devices generate ozone, which can neutralize pollutants and odours in the air. However, it’s important to note that ozone can be harmful to breathe in high concentrations, so these devices should be used cautiously.
It’s worth noting that these air-purifying devices can be effective in improving indoor air quality, but they should be used in conjunction with regular maintenance and filter changes.
Air-cleaning Plants
Air cleaning plants, also known as indoor plants, are a natural way to improve indoor air quality. These plants can absorb pollutants and toxins from the air through their leaves and roots and through the process of photosynthesis. Some common air-cleaning plants include:
- Spider plant: known for its ability to absorb pollutants such as formaldehyde, carbon monoxide and xylene.
- Snake plant: also known as mother-in-law’s tongue, it is known for its ability to absorb pollutants such as formaldehyde, nitrogen oxides and benzene.
- Aloe vera: known for its ability to filter out formaldehyde and benzene.
- Boston fern: known for its ability to filter out formaldehyde, xylene and toluene.
It’s worth noting that while indoor plants can be a great addition to improve indoor air quality, they should not be relied on as the sole means of air purification. They should be used in conjunction with other air-cleaning methods, such as HEPA filters or electronic air purifiers, to achieve optimal results and ensure that your home’s air is clean, fresh and healthy to breathe. Additionally, choose plants that are suitable for the level of light and humidity in your home, and also take care of them, giving them enough water, light and fertilizers.
Purifying Paint
Purifying paint is a type of paint that is specially formulated to improve indoor air quality by absorbing and neutralizing pollutants and toxins from the air. These paints typically contain active ingredients such as titanium dioxide, which have photocatalytic properties that help to break down and neutralize pollutants when exposed to light.
Some common pollutants purifying paint can neutralize include formaldehyde, volatile organic compounds (VOCs), and nitrogen oxides. This paint can be applied to walls, ceilings, and other surfaces in a home or building to improve indoor air quality.
It’s worth noting that while purifying paint can be a great addition to improve indoor air quality, it should not be relied on as the sole means of air purification. It should be used in conjunction with other air-cleaning methods, such as HEPA filters or electronic air purifiers, to achieve optimal results and ensure that your home’s air is clean, fresh and healthy to breathe. Additionally, ensure that the purifying paint you choose is high quality and meets safety and environmental standards.
Conclusion
Furnace filters play a crucial role in maintaining the health and efficiency of your HVAC system. Many different types of furnace filters are available on the market, including fibreglass, pleated paper, and HEPA filters, each with unique properties and benefits. When choosing a furnace filter, consider factors such as the size of your home or building, the type of HVAC system you have, and the specific needs and concerns of the people living or working there.
In addition to traditional furnace filters, some alternatives and supplements are available, including UV light systems, electronic air purifiers, ozone generators, carbon filters, air-cleaning plants and purifying paint. Each option can effectively improve indoor air quality, but it’s important to consider the cost, maintenance, and compatibility with your HVAC system.
Overall, by understanding the different types of furnace filters available and considering factors such as the size of your home or building, the type of HVAC system you have, and the specific needs and concerns of the people living or working there, you can make an informed decision that will help to keep your HVAC system running smoothly and improve the indoor air quality of your home or building.
