If you have a heating, ventilation and air conditioning (HVAC) system with an air filter, it's important to make sure you get the right replacement. Most filters have the sizes listed on the printed side, including length, width, and depth in inches. When you buy a new filter, you'll want to try to match it to the current filter. Check the brand, dimensions, and MERV rating of the filter that is already installed in your system.
Some filters may even have the part number you need on the label. HVAC filters are usually located in a slot next to the boiler or air controller. However, some air conditioning systems have filters inside the return air ducts scattered throughout several rooms in the house. These are the grilles that suck air inward, instead of expelling it. Air filters can vary significantly in size, so it's critical to make sure that the filter is the correct size for your unit.
Filters that are too small can let dust through both sides and reduce indoor air quality. The HVAC air filter plays an important role in the overall performance of the system. Not only do filters help keep the air you breathe cleaner, they also protect your equipment from damage. It's a good idea to replace your house filter whenever it's dirty. Because filters affect airflow, it's also important to buy the right size and type. When shopping for an air filter, look for one with a high MERV rating.
The higher the MERV rating, the more efficient the filter is at trapping particles like dust and pollen. It's not until FPRs 4 and 5 that filters begin to trap larger particles, such as household dust and lint, dust mites, pollen, and pet dander. One of the main advantages of thicker air filters with larger folds is that they don't need to be changed as often. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHARE) recommends a MERV 6 or higher. It is important to avoid using a filter with a MERV rating that is too high, as the airflow restriction caused by these high-efficiency air filters could cause additional wear and tear on older systems. If you currently have 1-inch filters, you might consider upgrading your system to include 4-inch filters.
Any pleated HVAC filter can improve your home's indoor air quality by trapping dust, pollen, and other small particles. If the filter is too dense, the heating or air conditioner may have to run for longer to counteract the increase in air resistance. For these reasons, and since all forced air heating and cooling systems use at least one filter, it's important to know how and when to change it. Filters that are too large for the system will not fit properly and could be damaged, allowing debris and particles of the filter material to pass through the mechanical components inside the air conditioning unit. While The Home Depot uses the FPR rating system for their filters, most manufacturers use Minimum Efficiency Value (MERV) ratings instead. Once you've found each filter, make sure it's the correct size by measuring its length, width, and depth (or thickness).
If you're still unsure about which filter is right for your system, check out your equipment owner's manual or contact the manufacturer.
