As an HVAC expert, I am often asked about the lifespan of furnace filters and how often they should be replaced. The answer is not a simple one, as it depends on various factors such as the thickness of the filter, the size of your home, and the level of air pollution in your area. However, there are some general guidelines that can help you determine when it's time to change your furnace filter. For 3- and 4-inch filters, it is recommended to replace them every six to nine months. If you have filters larger than 5 or 6 inches, they should be changed every nine to 12 months.
This is because thicker filters have more room to accumulate dirt and dust, so they don't need to be changed as frequently. The basic consensus among HVAC professionals is that you should replace your furnace filter every 90 days or every three months. However, this can vary depending on the thickness of the filter. For instance, Thomas & Galbraith Heating, Cooling and Plumbing of Ohio recommends changing filters that are less than 2 inches thick every 30 to 90 days. When it comes to 1-inch filters with a MERV rating of 6 to 8, they can last up to three months even with heavy use. However, if you have a 4-inch filter in a 1-inch filter spot, it can affect your energy bills.
MERV (Minimum Efficiency Reporting Value) is a rating that indicates how well an air filter can accumulate particles in the air in your home. In addition to traditional furnace filters, there are also options for whole-house air filters and rigid cell furnaces. Your specific situation is unique, but most air filtration experts agree that furnace filters have a general lifespan. It's important to note that not all HVAC systems require furnace filters, so you may not have realized that you need to change yours. If you want to improve air quality through better air filtration, but don't want to spend on modifying your equipment, a 13-inch MERV filter is a good option. This is particularly important for vulnerable parts such as the air purifier motor or oven fan, which work overtime to push and expel air through the dirty filter, and the heat pump or air conditioning compressor, which circulates refrigerant between outdoor and indoor units. Most HVAC technicians recommend changing 1-inch air filters every 30 days, while 4-inch filters can be changed every 3 to 6 months.
However, larger homes with larger volumes of air circulating may require more frequent filter changes. It's also important to note that Honeywell oven filters should not be confused with their HEPA air filters for purifiers, which have a longer lifespan. When it comes to cost, thicker oven filters tend to last longer and provide more filtration over time, so they may be more expensive than 1 or 2-inch filters. If you have pets in your home, it's especially important to choose a filter that can effectively remove pet dander and other pollutants from the air.
