This refers to how 'deep' the filter is. Always remember, the measurements are typically listed in this order: Length x Width x Thickness. So, if you've got a 20x25x1 filter, it's 20 inches long, 25 inches wide, and 1 inch thick. Get your measurements right and you'll never buy the wrong filter again.
To determine your air filter size, you need to measure its length, width, and depth. These measurements are usually printed on the side of the filter. If not, you can use a tape measure to get the dimensions.
Usually they round up or down to the nearest inch, so it is less likely that these two filters will fit the same furnace because of the rounding. However, if your filter is close to 20x25x4. 5, and the actual dimensions of the 20x25x5 filter are closer to 20x25x4. 5, than they might fit.
In most cases, a MERV 11 air filter isn't too high for residential use. Generally speaking, anything under a MERV 13 air filter should provide very efficient air purification in a home without impacting airflow.
Just adding a 1 inch pleated filter may be detrimental to your system if it is border line already. The best thing to do is upgrade to a 2 inch filter or even a 4 inch filter. Many cabinets allow for either a 1 inch or a 2 inch filter.
Well, 4-inch filters have larger pleats. That means they have more surface area to catch particles, making them last 3–5 times longer than 1-inch filters. Most HVAC technicians recommend changing 1-inch air filters every 30 days, while 4-inch filters can be changed every 3–6 months.
UNDERSTANDING FILTER SIZES
Therefore, for example, a 16x25x4 filter is 16 inches long, 25 inches wide, and 4 inches thick. It's important to note that filters with different dimensions are not interchangeable due to variations in frame size and media area.
The MERV 11 air filter is the wrong choice for people who do not own pets and do not have any breathing trouble; this is because it can lead to restricted airflow. Air filters with higher ratings can also have negative effects on HVAC components.
MERV‑8 filters are among the most popular choices because they strike a balance between performance and adaptability, fitting most systems without modifications. However, it's worth noting that filters with higher MERV ratings can restrict airflow.
High-MERV filters increase the static pressure of your system, and if the ductwork is already marginal, this can cause the airflow to drop to a level where the temperature exceeds the furnace's limit.
Using the wrong size filter reduces efficiency, air quality, and can even damage your HVAC system. You can learn more about the difference between furnace and AC filter sizes here.
Fortunately, most 20x25x4 air filters last between six to eight months. By that calculation, the average homeowners will not need more than two 20x25x4 air filters in any given year. In contrast, a one-inch air filter will need to be changed every two to three months.
Air filters rated between 8 and 13 are best suited for homes. Filters below 8 don't trap enough particles to achieve good air quality; filters above 13 are not necessary and are not usually compatible with home HVAC systems.
Generally, most air filter manufacturers and HVAC companies recommend changing your air filter every 90 days, or 3 months. That can change based on where your home is located (ex. dusty, dry climates), if you have any pets, and the age of your system and equipment.
The lower the MERV number, the less effective the filter is at capturing particles (measured in microns) from the air. As the value increases, the filter captures smaller and smaller particles at a higher rate but also restricts airflow.
If the air filter is too large, it will cause the system to run slowly and reduce the efficiency of the filtration process. This requires more energy to run during the day and will increase your bills.
Sometimes, a MERV 11 filter may be too restrictive, particularly for older or smaller HVAC systems not designed to handle the increased pressure drop. If you notice that airflow has diminished or your HVAC unit is cycling on and off more frequently, these could be signs that your filter is too restrictive.
What Is the Best MERV Rating for a Residential Home? The best MERV filter for a home is typically between 8 and 13. With the right media, this strikes a good balance of air filtration and efficiency.
Because not all HVAC systems can use HEPA filters, air filters with a MERV rating of 13 to 16 are the best option to trap pollen, pet dander, mold spores, and dust mites, and they're highly effective for reducing allergens and improving indoor air quality.
There is still a common misconception that having a high MERV rated filter will be too restrictive and strain your unit. However, most HVAC systems built in the last 20 years should have no issue using a MERV 6 - MERV 13 rated air filter.
A good MERV (Minimum Efficiency Reporting Value) rating for residential HVAC systems is typically between 8 and 13. MERV 8 filters capture basic particles like dust, pollen, and pet dander and are adequate for most households.
Many New Jersey homeowners ask us about MERV ratings, especially when it comes to choosing between MERV 8 and MERV 11 air filters. Here's what we tell them: Think of MERV 8 filters as a “good” option, and MERV 11 filters as the “better” option for normal residential use.
If you try to use a 4-inch thick air filter for a system that's made for a 1-inch thick filter the efficiency will actually be worse. Not to mention, components could get damaged in the process. On the other side, you can certain use a 1-inch thick filter in compartments that can accommodate a deeper filter.
You can use a 20x25x4 filter instead of a 20x25x5. But it might not securely fit and may not be that efficient.
A MERV 11 filter is the most popular choice for residential homes. This type of filter can remove most of harmful contaminants from a home environment, including smoke, dust mites, pet dander, mold, pollen, dust and smog. MERV 11 filters can remove around 90% of foreign particles found in air.