Often, we are asked by our customers what type of air filter they need in their air conditioning system. It’s not that simple of a question. After all, systems are different, from sizing to installation and customer’s lifestyles are different, from pets, to cleaning habits, to how often they change their filters. In this article, we are going to break down the different types of filters to help you decide what is the correct type of filter for you and your home. We do hear the question a lot “Shouldn’t I just buy the cheapest filter” and the answer to that more often than not is no.

As a homeowner, maintaining proper airflow and filtration in your HVAC system should be a top priority. The right air filter will ensure your heating and cooling equipment operates efficiently while improving the indoor air quality in your home. However, with so many options available on the market today, determining the appropriate filter for your needs can be an overwhelming task. This guide will walk you through the key considerations to select an air filter that balances high performance with cost-effectiveness for your specific HVAC setup. By understanding the various filter types, sizes, and ratings, you can make an informed choice that maximizes system performance and enhances the comfort and health of your home environment. With regular maintenance and the proper filters, your HVAC system can provide consistent temperature control and cleaner air for years to come.

HVAC Air Filter Types: Pleated, HEPA, Electrostatic – Which Is Best?

As a homeowner, one of the most important things you can do to keep your HVAC system running efficiently is to install the proper air filter. But with so many options out there – pleated, HEPA, electrostatic – how do you know which is right for your needs?

Pleated Air Filters

Pleated air filters are the most common and inexpensive type. Made of polyester or cotton, pleated filters trap large particles like dust, pollen, and mold. While pleated filters are affordable and energy efficient, they typically only last 3-6 weeks before needing replacement. For the average homeowner looking for basic air filtration, pleated filters can work well.

HEPA Air Filters

HEPA (High-Efficiency Particulate Air) filters are the gold standard for air filtration. Made of ultra-fine fibers, HEPA filters can capture at least 99.97% of airborne particles including large and small particles like pollen, dust, mold, bacteria and some viruses. HEPA filters provide the highest quality air filtration but tend to be more expensive and may reduce airflow, making your HVAC system work harder. HEPA filters typically last 3-6 months before needing replacement.

Electrostatic Air Filters

Electrostatic air filters use an electrostatic charge to attract particles and pollutants. They are very efficient at capturing particles and can last 3-6 months. However, some studies show they may emit ozone, an air pollutant. They also lose efficiency over time and as they get dirty. For the best indoor air quality without the risks, a HEPA filter is a safer choice.
In summary, for basic and affordable filtration, pleated air filters work fine for most homes. For maximum filtration and the cleanest indoor air, HEPA filters cannot be beat, though they do cost more. For high performance with some risks, electrostatic filters are an option. The choice is ultimately up to you and your needs for clean, quality air in your home.

MERV Ratings: What Do They Mean and Which Should You Choose?

The MERV rating stands for Minimum Efficiency Reporting Value and indicates an air filter’s ability to capture larger particles between 0.3 to 10 microns in size. The higher the MERV rating, the more effective the filter is at removing particles from the air.
For most homeowners, a MERV rating between 7 to 13 is adequate for typical residential HVAC systems.

MERV 7-8:

These are basic 1-inch filters that can remove large particles like dust, pollen, and mold. They are inexpensive but only provide minimal filtration. We do not recommend anything below a MERV 7.

MERV 9-12:

Mid-range filters that can capture smaller particles like pet dander, dust mites, and some smaller mold spores. MERV 10-12 are a good choice for most homes and provide a good balance of performance and cost.

MERV 13 and above:

These are high-efficiency filters that can capture even smaller particles like smoke, bacteria, and some viruses. They provide the best indoor air quality but also tend to be more expensive and can reduce airflow in some HVAC systems. We only recommend a MERV 13 or higher if you have allergies or respiratory issues and have consulted an HVAC professional.

In summary, for the typical homeowner looking to balance performance, cost, and HVAC efficiency, we recommend starting with a MERV rating of 10-12. Be sure to check your HVAC manual to ensure your system can handle the level of filtration and any reduction in airflow before purchasing higher-rated air filters. Clean or replace your filters regularly according to the filter and HVAC specifications to keep your system running efficiently and your indoor air clean.

When Should You Change Your Air Conditioner Filter?

As a homeowner, replacing your HVAC air filters regularly is one of the most important maintenance tasks you can perform. Not only will clean filters improve your system’s efficiency and longevity, but they will also enhance the air quality in your home.

For optimal performance, most HVAC experts recommend changing your air filters once every 3 months or so. However, the frequency can vary depending on several factors:

Filter Type

The type of filter you use, like pleated, HEPA or electrostatic, will impact how often it needs replacement. Pleated and HEPA filters typically need changing more frequently, around once every 3 months. Electrostatic filters can often last 6-12 months before needing replacement.

System Run Time

If your HVAC system runs frequently to heat or cool your home, your air filters will get dirtier faster. In this case, checking and possibly changing them every 2 months is a good rule of thumb. For homes in milder climates where the system runs less, you may be able to stretch replacement to every 4-6 months.

Presence of Allergens

Homes with pets, smokers or a lot of airborne allergens like pollen may require more frequent filter changes, around every 1 to 2 months. Dirty, clogged filters cannot capture these pollutants effectively and will not provide adequate indoor air quality.

Signs It’s Time for a Replacement

Some indicators that it’s time for a new furnace filter include: increased dust in the home, musty smells coming from vents, higher energy bills, noisy or rattling sounds from the HVAC unit, or visibly dirty, bent or damaged filters. Replacing your filters at the first sign of these issues will ensure maximum efficiency and help prevent costly HVAC repairs or damage down the line.

Following the recommended schedule for changing your air conditioning filters is one of the easiest ways homeowners can keep their HVAC system running smoothly while improving the quality of air in their home. Be sure to check and replace your filters regularly for optimal comfort, health and energy efficiency.

How to Choose the Right Size Air Filter for Your HVAC System

Choosing the correct size air filter for your HVAC system is crucial for optimal performance and energy efficiency. The air filter removes airborne contaminants before the air circulates through your home. If the filter is too small, it will not filter properly and your HVAC system has to work harder. If it is too large, it won’t fit correctly and can damage your HVAC equipment.

To determine the right size filter, you will need to check your HVAC system owner’s manual for the specific filter size recommendation. It is typically listed as the size in inches, such as 20x25x5. This indicates the height by width by depth of the filter. You should always follow the size guidelines recommended for your specific unit.

If you do not have the owner’s manual, you will need to measure the existing air filter to get the correct sizing. Turn off your HVAC system and furnace at the breaker before removing the existing filter to measure it. Use a tape measure to determine the height, width and depth in inches. Be very precise in your measurements. Write down the dimensions and take them with you when purchasing a new filter.

Some common residential HVAC filter sizes are:

  • 16x25x1 – For small furnaces and some air handlers
  • 20x25x5 – A very common size for most furnaces
  • 14x20x1 – Used in some air conditioners and heat pumps
  • 12x24x1 – For some air handlers and packaged units
  • 16x20x1 – Another size option used in various HVAC systems

Choosing the proper size air filter is key to maximizing the effectiveness of your HVAC system. Be sure to replace your air filters at least every 3 months, or more often if you live in a dusty area or have pets. Clean, efficient filters will improve your home’s air quality and help lower energy costs. For the optimal performance of your HVAC equipment, the right size air filter is paramount.

The Best Air Filters for Your HVAC System: Our Top Recommendations

When choosing an air filter for your HVAC system, selecting the proper type and efficiency rating is important for the health of your home and family. The correct air filter will help ensure good indoor air quality by trapping airborne contaminants like dust, pet dander, mold spores, and other allergens. It will also keep your HVAC system running efficiently by preventing buildup in air vents, ductwork, and components.

We recommend considering a pleated air filter for most residential HVAC systems. Pleated filters offer a large surface area in a compact size, allowing for effective filtration without significantly reducing airflow. Look for a pleated filter with a Minimum Efficiency Reporting Value (MERV) rating of 8 to 13 for the best balance of efficiency and airflow for a typical home. Higher MERV ratings, from 13 to 16, offer greater filtration for those concerned about allergies or respiratory issues but may require an HVAC system with a more powerful fan to maintain adequate airflow.

For the best performance, check your HVAC system’s filter size and replace the air filter every 30 to 90 days depending on the filter’s MERV rating and how much it has accumulated. A dirty, clogged air filter reduces airflow and efficiency, costing you money and compromising the comfort of your home. It may also cause damage to your HVAC components over time.

Some highly-rated pleated air filter options we recommend for most homes include:

  • 3M Filtrete Ultra Allergen Reduction Filter (MERV 13) – Offers effective filtration for allergens like pollen, pet dander, and dust mites. Replace every 90 days.
  • Honeywell Home Enviracaire Permanent HEPA-Type Air Filter (MERV 12) – A long-lasting, reusable option that can be vacuumed and lasts up to 5 years. Great for those wanting to reduce waste.
  • Filtrete Advanced Allergen Reduction Filter (MERV 12) – An affordable, entry-level pleated filter that can effectively capture large airborne particles like pollen, dust, and mold. Replace every 60-90 days.

Choosing the proper air filter for your HVAC system and changing it regularly is one of the best ways to improve the comfort and wellbeing of your home. Be sure to check your HVAC system specifications to determine the correct filter size and type, and consider consulting an HVAC professional if you have any questions about what filter is right for your needs.


With so many options available, choosing the right HVAC air filter for your home can be an overwhelming decision. However, by understanding the fundamentals of how air filters work and knowing the specific requirements of your HVAC system, you can make an informed choice. Evaluate how much filtration you need based on the occupants and layout of your home. Then determine which filter type, MERV rating and size will work best for your unit. While price is certainly a factor, don’t forget that more efficient air filters can save you money over time through lower energy bills and reduced repairs. By taking the time to choose wisely now, you’ll be breathing cleaner, fresher air for years to come. Your HVAC system and your health will thank you.

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