The filters are smaller than their slot for easy replacement. Some HVAC units may require a filter with unique or unusual dimensions. If you have to force the filter into its slot, it's probably too big. Inserting an incorrectly sized filter may cause it to deform, damage it, or reduce its ability to function properly.
In these cases, it is necessary to order a custom filter. If your system only fits a 1- or 2-inch filter, a high MERV rating could be detrimental. A 1-inch filter with less surface space will clog up fairly quickly and will need to be replaced much sooner than a coarser filter. Combining a thin air filter with a high MERV rate can also restrict airflow to the point of hampering efficiency and causing excessive wear.
You may have heard your air conditioning technician tell you that you should replace your home air filter every 3 months, or 90 days. But why is this important? Before we talk about WHEN you should change your air filter, let's start with the WHY. When you buy your air filter online, the most important thing to know is that air filters come in two sizes: nominal size (which is a round size often used to label the filter) and actual size. A deeper depth can also improve filter life and efficiency; it also makes it easier for air to enter and exit the filter.
If you try to use a 4-inch-thick air filter in a system designed for a 1-inch-thick filter, the efficiency will actually worsen. Fortunately, the American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) has developed a standard classification system that the air filter industry follows. It's important to note that there are high-efficiency filters designed to filter small particles of bacteria, mold, and mildew, but standard MERV 8-11 filters only block the largest dust particles and 26% of hair. The 4-inch thick air filter has a definite advantage over the single filter in terms of longevity, airflow and maximum filtering potential.
The secret is that they can capture tons of waste using relatively porous filtering material, thanks to the enormous surface area through which dirty air passes - approximately four times more filter material than a 1-inch filter. For example, the filter label may have a size of 20x30x1, but if you measure the filter you will see that the actual size is smaller than the nominal size of the air filter of 20x30x1. Air filters are usually made of spun fiberglass (the same that forms the insulation of the attic) or pleated paper (26%) framed with cardboard for greater stability and rigidity. But what if the air filter compartment in your oven is only 3 mm thick? In that case, the 1-inch oven filter is the better choice compared to the 4-inch filter; however, a 3-inch thick air filter is the better option. It's essential to understand that using an incorrect size air filter can cause serious damage to your HVAC system and reduce its efficiency.
To ensure optimal performance and longevity of your system, make sure you use an air filter with the correct dimensions for your unit. If you're unsure about what size air filter you need for your system, consult an HVAC professional.
