When it comes to HVAC systems, many professionals will tell you that thicker filters are better than the standard 1-inch oven filters. These thicker filters, known as media filters, are usually 4 to 5 inches thick, while the 1-inch filters are more commonly found in grocery stores. When you're changing your oven filter, the first thing you need to do is to determine the size of the filter. To measure an air filter, you just need to round up to the nearest inch to get the dimensions of the filter you need.
Look for where the return duct connects to your oven and there should be a plate covering the slot where the air cleaner enters. If the filter is too large, it won't fit into the slot and you won't be able to replace the cover. When buying a new filter, make sure it's true to size by looking for “true size” printed next to the filter dimensions. For HVAC ventilation grilles located on roofs, a slightly larger filter size can be used to prevent it from falling out when the vent is opened.
The density of the filter fibers is another factor to consider when it comes to filter width. The MERV air filter rating is a measure of how effective an air filter is in removing particles from the air. Dense filters tend to get covered in dust and dirt more quickly and clog faster than filters with a lower MERV rating. In conclusion, when installing thicker filters on a return grid, make sure that the return duct is completely sealed and airtight.
When buying a new filter, order it by its nominal size rather than its actual size. Your oven filter has an important job of filtering out all the dust and debris that gets between your oven, air ducts and lungs.