The Difference Between One-Inch and Four-Inch Filters The four-inch-thick air filter has an advantage over the one-inch in terms of longevity, airflow and maximum filtering potential. If it fits your furnace, then a four-inch air filter will provide better air quality.
actual size of an air filter can affect filter compatibility if it doesn't fit properly into the HVAC system filter slot. Ensuring the actual size aligns with your HVAC system's requirements, even when the nominal size matches, is important if you want system efficiency, proper filtration, and the best performance.
Selecting an incorrect size might appear insignificant, but it seriously hampers your system's performance and lifespan. Such a minor mistake leads to compromised efficiency and airflow restriction, which result in higher energy use, more maintenance work, and the need for frequent replacements.
Going down in thickness by an inch shouldn't be a big deal - for example, you should be able to use a 4-inch filter instead of a 5-inch filter. If you are considering a thicker air filter in order to improve air quality it may be better to focus on the MERV rating.
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.
You can use a 20x25x4 filter instead of a 20x25x5. But it might not securely fit and may not be that efficient.
This extra depth gives the filter more room for airflow. That means that as the filter collects dirt and other debris from your air, it won't restrict the airflow in your furnace as much. This prevents damage to the furnace and gives the filter itself a longer lifespan.
What Is the Most Common Size of Air Filter for a House? The most common size air filter for a house is usually 20 x 20 x 1, but this can vary depending on the specific HVAC system installed.
Because it is four times as thick as a 1-inch filter, it has a much greater surface area for catching household pollutants. These larger filters also typically come with higher MERV ratings and can capture more contaminants (e.g., pet dander, smoke, allergens, and bacteria) than a 1-inch filter.
Stiffer builds for steadfast seal: 1-inch filters have less material to control, which means the frames are thinner. Thin frames have flimsy seals which let through unfiltered air, defeating the purpose of your filter. 5-inch frames are thicker and fit into the furnace more seamlessly.
What problems can a backward filter cause? The most common thing you will notice is the inefficiency of the filter. It will be harder for the air to flow, which would take a toll on your system. More strain means spiked utility bills.
Your furnace can, technically, run without a filter. However, we strongly recommend you don't run your furnace without a filter for any length of time. With air constantly moving through your furnace and your home, dust and debris can quickly build up, even in a matter of minutes.
There are Different Filter Sizes
You cannot buy just any furnace filter and expect it to fit. You will need a furnace of a specific length, width, and height in order to replace your current filter. The simplest way to do this is to look at the current filter you have and match the new ones to it.
The four-inch-thick air filter has an advantage over the one-inch in terms of longevity, airflow and maximum filtering potential. If it fits your furnace, then a four-inch air filter will provide better air quality. The cost difference is often minimal.
Damage to the HVAC System
Reduced Efficiency of the System: An improperly sized air filter can create an imbalance in the airflow, which means the system may not operate at its designed efficiency.
Home size, room size and HVAC slot size will impact the amount and type of filters you'll need. It may sound strange, but size has many implications for air filters. The size of your home, size of individual rooms and size of your HVAC filter slot can all come into play when it comes time to buy new air filters.
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.
For 1- to 2-inch filters, replace them every 1 to 3 months. For 3- to 4-inch filters, replace them every 6 to 9 months. For 5- to 6-inch filters, replace them every 9 to 12 months.
The easiest way to find out what size filter to get for your furnace is to simply remove your current filter and look at its dimensions. These are typically printed along with one of the sides of your filter.
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.
Pleated filters are denser than fibreglass filters, and their wavy design creates more surface area to capture more dust. They have higher MERV ratings and are generally cost-efficient, ranging in price depending on quality, size, and manufacturer.
The abbreviation stands for Minimum Effective Reporting Value. In other words, it's a measurement showing how small the holes are in the filter. The higher the MERV number, the smaller the holes, and the less that can pass through. Ultimately, this is what makes MERV 14 filters not a good choice for home use.
Pleated filters can restrict airflow slightly more than non-pleated ones, but they balance filtration and airflow. Choosing the right MERV rating (between 8 and 13) ensures your system gets proper airflow while still effectively filtering the air.
With the 2 inch pleated filter, even though it is smaller, we have a static pressure of 0.158” WC. As you can see the 2 inch filter will serve our needs MUCH better than the 1 inch filter. Even if the duct system is in good shape, using this filter will keep the system from struggling.