The nominal size of an air filter refers to the size of the filter slot. Therefore, a 20x20x1 filter is designed to fit into a 20x20x1 groove.
Interestingly, 70% of what Filterbuy sells isn't included in the 10 most common air filter sizes.
To make sure you have the right size filter, especially if you are replacing it with a different brand, it's important to confirm the actual size of the filter. Medium-efficiency MERV filters, such as the Nordic Pure MERV 12, can significantly reduce airborne dust, mold spores, pollen and even smoke, according to an NIH study.The MERV rating reflects the performance of a filter across all its components. The air is charged with particles, passes through the filter only once, and the results are measured. When used in real-world conditions, the air in your home is constantly recirculated through the ducts and passes through the filters each time, resulting in a cumulative effect. Later, he chaired the ASHRAE 52.2 committee, which regularly updates the standard to address changes in filter technology. Whether or not to pay more for a better filter depends mainly on whether or not cleaner air is a priority for you.
If your HVAC system uses a thicker filter (typically 4 to 5 inches and usually mounted on the air handler), it's likely specifically designed for medium-efficiency MERV filtration. Clogging increases the pressure difference between the inlet and outlet sides, and this can cause the filter folds to flatten or the filter frame to bend. On the other hand, if the filter is too large, the frame will wrinkle, airflow will be restricted, and longevity will be compromised. Most people won't be able to find the size air filter they need at their local home improvement store. If the filter is too small, it will be loose and some of the air (and debris) will not pass through. As an expert in SEO optimization, I'm here to explain what is the difference between a 20x20x1 and a 20x25x1 air filter.
The nominal size of an air filter refers to its dimensions and how it fits into its slot. A 20x20x1 air filter is designed to fit into a 20x20x1 groove while a 20x25x1 air filter is made for a 20x25x1 groove. It's important to note that 70% of what Filterbuy sells isn't included in the 10 most common air filter sizes so it's essential to confirm your actual size before purchasing a new one. Medium-efficiency MERV filters such as Nordic Pure MERV 12 can reduce airborne dust, mold spores, pollen and even smoke according to an NIH study. The MERV rating reflects how well a filter performs across all its components when tested in laboratory conditions.
In real-world conditions however, air is constantly recirculated through ducts and passes through filters multiple times resulting in a cumulative effect. The ASHRAE 52.2 committee regularly updates standards to address changes in filter technology. Whether or not you should pay more for better filtration depends on your priorities - if cleaner air is important to you then investing in higher quality filters may be worth it. If your HVAC system uses thicker filters (usually 4-5 inches mounted on an air handler) then it's likely designed for medium-efficiency MERV filtration. It's also important to consider size when purchasing an air filter - if it's too large then airflow will be restricted and longevity compromised while if it's too small then some of the air (and debris) won't pass through.
