When it comes to air filter sizes, it is essential to have the correct dimensions for the filter to work properly. There are many common and uncommon sizes available, and it is important to understand the differences between them. Generally, air filters should be replaced every three to twelve months, depending on their size. For 1-inch-thick filters, the usual recommendation is three months, while for filters that are 4 inches or thicker, twelve months will normally pass.
Many manufacturers also claim that their HVAC filters are “allergen filters” or something similar. However, these are usually only filters with a rating of at least MERV 11, which is the classification in which filters begin to trap most particles the size of common allergens. There is nothing exclusively anti-allergenic about these filters, and other filters with the same MERV rating should capture allergens just as well. An easy way to choose a replacement filter is to simply purchase the same filter you're already using in your system. But if that's not available, or if you prefer something that costs less or performs better, there are a few steps you can take.
Air filters generally come in a variety of standard sizes, and some can be adapted to fit different-sized filter boxes or air return openings. Pay special attention to the thickness, as it will affect the next decision you have to make. Most residential HVAC filters are 1 inch thick, but 4-inch filters are also becoming common. Remember how we said you should take special account of the thickness of the filter? This is where that detail becomes important, as it could affect the amount of filtration your system can withstand. However, Consumer Reports has tested several 1-inch filters with high MERV (MERV 11 and higher) that score very well in their airflow test.
These tend to be quite expensive but offer excellent air quality at a reasonable price. The models that score the highest in Consumer Reports' airflow test also tend to have lower MERV ratings and cost less, although they don't perform as well in their particle capture tests. Consumers can see the best results in their comprehensive air filter rankings. The secret is that they can capture tons of waste while using a relatively porous filter material, thanks to the enormous surface area through which dirty air has to pass - approximately four times more filter media than in a 1-inch filter. A MERV 13 is an excellent choice at this size. If you currently have 1-inch filters, you might consider upgrading your system to fit 4-inch filters.
Your HVAC professional would install a small cabinet next to the boiler or air handler (on the side of the air intake) to hold the thicker filter. The job should only cost hundreds (not thousands) of dollars. What is the difference between an air conditioning filter, a furnace filter and an air conditioning filter? Absolutely nothing! What you call it depends on where you live - people in the north might call it a furnace filter, while those in the south might call it an air conditioner filter. Just know that no matter what you call it, it's simply an air filter. For example, there may be a size of 20 x 30 x 1 on the filter label, but if you measure it, you'll see that the actual size is smaller than the nominal air filter size of 20 x 30 x 1.Be sure to install the new filter facing in the right direction; look for arrows on the filter frame that indicate the direction of the air flow. Even worse, improperly sized air filters can put undue pressure on your HVAC system, damaging it and increasing your energy bills. Of course, this sounds easy when you hear the term “standard air filter size”; you might think that if your air filter is standard, it will be easy to find it when you get to the store. If your filter has no actual dimensions on the outside of the filter, you can measure it yourself to get the correct dimensions.
You can choose how much filtering you need and get a replacement air filter that's right for your home. We also control the extent to which each filter restricts airflow using a differential pressure transducer installed in the air filter. Any pleated air conditioning filter can improve your home's indoor air quality by trapping dust, pollen and other small particles such as a quieter more passive vacuum. When HVAC filters become dirty and clogged with debris, air can't flow freely through the ductwork making your home less comfortable and eventually damaging your HVAC equipment.
