How To Choose The Right Furnace Filter

Air Filter Buying Guide: Choosing the Right HVAC Filter

August 23, 2021

Although they seem small in comparison to the size of the whole HVAC system, a standard furnace filter plays a big role in your family’s comfort. Using the wrong type of filter or not replacing it regularly could result in poor air quality for your home and strain on your blower fan. Selecting the right furnace filter size is essential for maximizing performance, improving indoor air quality, and ensuring the cost-effective operation of your heating and cooling system.

What to Consider When Buying a Standard Furnace Filter

When purchasing a new furnace or HVAC filter, focus on the most important considerations:

  • Furnace filter size
  • HVAC filter thickness
  • MERV rating

We'll expand on all of these important characteristics and review various types of standard air filters, highlighting their unique features and benefits so you can confidently select the best option tailored to your specific needs and preferences.

Common Air Filter Sizes

When considering the size of a home furnace filter, it's important to understand the range available in the market. The dimensions of air filters typically vary to accommodate different sizes of HVAC units and air circulation requirements. For instance, the smallest standard HVAC filter size is 10x10x1 inches, suitable for compact residential systems or smaller areas where space is limited. On the other end of the spectrum, the largest standard air filter size is typically 25x25x1 inches, often employed in larger residential or commercial settings where higher air circulation rates are necessary to maintain indoor air quality. You’ll typically find these extremely common sizes in hardware and home improvement stores:

  • 16x20x1
  • 20x20x1
  • 16x25x1
  • 20x25x1

In addition to varying dimensions, air filters also come in different thicknesses, ranging from 1 inch to as much as 6 inches. The thickness of a filter, indicated as the third number in the size, can significantly impact its filtration capabilities and longevity. Thicker filters generally have a greater surface area and can capture more particles before requiring replacement. This makes them ideal for environments with higher levels of airborne contaminants or for individuals with respiratory sensitivities who require cleaner air.

However, the trade-off with thicker filters is that they may restrict airflow more than thinner ones, potentially putting strain on the HVAC system if not properly sized and maintained. Therefore, it's crucial to consider the balance between filtration efficiency and airflow when selecting the thickness of a furnace filter. We understand there are lots of considerations to take in when looking for a home air filter, and that’s what our HVAC technicians at Lozier are here for! We’re only a text or call away to help you find your perfect hvac filter.

What Is the MERV Rating?

The MERV (Minimum Efficiency Reporting Values) rating is a standard measure used to rate the effectiveness of air filters in trapping airborne particles. It quantifies a filter’s ability to capture particles of various sizes, like dust and pollen to mold spores and bacteria. The rating ranges from 1 to 20, and the higher the MERV rating, the better the air filter is at trapping specific types of particles.

While you should consider the specific air quality needs of your home, it's also essential to ensure that your chosen filter's MERV rating is compatible with your HVAC unit. Higher MERV-rated filters may restrict airflow if your heating and cooling unit is not designed to handle them.

Common Home Furnace Filter Types

In the quest for cleaner, healthier indoor air, homeowners are increasingly turning to a variety of air filtration solutions. From combating allergens to eliminating odors, the range of common home air filter types available offers a diverse array of options to suit every household's needs. Understanding the nuances of these filters is key to making informed decisions about indoor air quality. Whether you're seeking basic particle filtration or advanced odor elimination, join us as we delve into the world of air filtration and discover the perfect solution for your home.

Disposable Fiberglass HVAC Filter

  • Composition: Fiberglass mesh stretched over a cardboard framework
  • MERV rating: 1-4
  • Reusability: None - fiberglass HVAC filters are single-use filters

Flat-panel filters catch debris as the air passes through. Disposable fiberglass HVAC filters are the most common and most affordable type of furnace filter, but they must be regularly replaced in order to maintain HVAC efficiency and air quality. While they may not provide the highest level of filtration efficiency, they are suitable for environments where budget is a primary consideration and air quality concerns are relatively minimal.

Washable Mechanical Home Air Filter

  • Composition: Woven polypropylene media with an electrostatic charge
  • MERV rating: 1-4
  • Reusability: Washable HVAC filters can be washed and reused

These standard air filters can be rinsed with water or vacuumed to remove any ­particle buildup. They typically consist of a frame made of durable materials such as metal or plastic, housing a filter made of materials like foam, polyester or cotton. The filter catches airborne particles such as dust, pollen and pet dander as air passes through the HVAC system, improving indoor air quality.

One of the key advantages of washable mechanical filters is their reusability. Instead of disposing of the filter when it becomes dirty, homeowners can remove the filter from the HVAC system, wash it with water and mild detergent, and allow it to dry thoroughly before reinstalling it. This not only saves money on filter replacements but also reduces waste and environmental impact. Two things to note are that washable mechanical filters might have a higher initial cost compared to disposable filters, and they will require frequent cleaning to maintain performance. Overall, this type of furnace filter offers a reusable and customizable air filtration solution if you’re seeking a balance between cost-effectiveness, environmental sustainability and great indoor air quality.

Disposable Pleated HVAC Filter

  • Composition: Dense, pleated layers of cotton or plastic fibers
  • MERV rating: 5-12
  • Reusability: None - pleated HVAC filters are disposable

A Disposable pleated heating and cooling filter is a single-use filter with pleated layers made out of materials such as polyester, paper or synthetic fibers. They are available in a wide range of MERV ratings, which indicates their ability to capture particles of various sizes. Higher MERV-rated pleated filters offer better filtration performance, trapping smaller particles and providing cleaner indoor air. These filters are designed for single-use and must be replaced periodically, typically every one to three months, depending on factors such as air quality, usage, and the manufacturer's recommendations. They’re on the pricier side, but they’re available in various sizes to fit different HVAC systems, making them a versatile option for both residential and commercial needs.

HEPA Home Air Filter

  • Composition: Borosilicate glass fibers or plastic fibers
  • MERV rating: 16+
  • Reusability: HEPA furnace filters are available in disposable or washable options

HEPA stands for High Efficiency Particulate Air. HEPA filters are highly effective at removing particles from the air and are commonly used in settings such as medical clinics, hospitals and laboratories, where extremely pure air is especially important. HEPA filters are constructed from a dense mat of randomly arranged fibers. These fibers create an intricate maze-like area that traps particles as air passes through the filter, which makes it one of the most expensive air filters on the market. To qualify as a true HEPA filter, it must meet certain standards set by government agencies, such as the United States Department of Energy (DOE) or the European Union.

UV HVAC Filter

  • Composition: Ultraviolet light
  • MERV rating: N/A - UV filters are not given MERV ratings like other types of filters
  • Reusability: N/A - there is no physical filter, UV HVAC filters are neither washable nor disposable

A UV heating and cooling filter, also known as a UV air purifier or UV germicidal lamp, is a type of air filtration system that incorporates ultraviolet (UV) light to kill pathogens and microorganisms such as bacteria, viruses, mold, and fungi that may be present in the air or on the surfaces of HVAC units. As air circulates through the unit, any microorganisms present in the air or on the surfaces of the system are exposed to the UV light. The light effectively destroys these microorganisms, helping to improve indoor air quality and reduce the spread of airborne pathogens.

How Often Should I Replace My Furnace Filter?

There is no standardized rule about how often to change your furnace filter, but the ideal cadence for replacing most furnace filters is at least once every 3 months, depending on what type of filter you have and the type of air quality you live in. If you are sensitive to airborne allergens or if you have pets in your household, it can be a good idea to replace your furnace filter every month.

Regularly replacing your furnace filter improves indoor air quality and helps your HVAC system run more efficiently. A clogged filter restricts airflow, making your system work harder to heat or cool your home. This can lead to higher energy bills and premature wear and tear on the system. By following a regular filter replacement schedule, you can maintain a healthier indoor environment and prolong the lifespan of your HVAC unit.

How To Replace Your Home Air Filter

Due to its placement in the unit, the furnace filter can be tricky to locate. If you are unsure where the filter box is, look at the ductwork. The heating duct is located near or at the top of the furnace, and the cold air return is located near the bottom, which is where the filter box will likely be located. Once you’ve located the filter box, follow these steps to replace your standard furnace filter. These steps may differ slightly depending on your home HVAC unit.

  1. Locate the filter box door or possibly a notch that the home air filter slides into.
  2. From here, remove the old filter and discard it.
  3. Look at your new filter and find the airflow arrows along the sides. The arrows indicate the correct orientation of the filter.
  4. With the arrows pointing toward the furnace, slide the furnace filter into the air box.

Still Not Sure If You’re Choosing The Right Home Furnace Filter? Call Lozier!

If you have more questions about choosing the right HVAC filter or how to change one, call the heating and cooling experts at Lozier Heating & Cooling. A technician can come out and provide a furnace inspection, along with home air filter recommendations based on your setup and your household needs. Request an inspection appointment or give us a call today at 515-267-1000!