The general consensus among HVAC professionals is that furnace filters should be replaced every 90 days or every three months. However, that depends on the thickness of the filter. Thicker filters have more room to accumulate dirt and dust, so you don't need to change them as often. Thomas & Galbraith Heating, Cooling and Plumbing, of Ohio, recommends changing filters less than 2 inches thick every 30 to 90 days.
Three- or 4-inch filters can last 6 to 9 months, and filters up to 6 inches thick can be replaced once a year. When it comes to MERV ratings, the basic recommendation is that oven filters be changed at least once every 90 days for MERV 8, every 6 months for MERV 10 and 11, and every year for MERV 16. However, because filters with higher MERV ratings are denser, the oven must work harder to get air through them, and not all ovens have enough power to do so. Many of the one-inch filters you can buy at Home Depot and Lowe's are cheap filters that can be MERV 4 or 5 or less. Thanks to their folds, filters such as the Honeywell Ultra Efficiency filter (also available on Amazon) have more square inches of space to trap dust, so they usually require fewer changes, usually every 90 days.
However, people with allergies who have respiratory sensitivity may prefer to use a filter with a higher MERV rating. If your oven can handle it, use a filter with a MERV rating of 12 such as the Nordic Pure Filter (available on Amazon). Filters are often assigned a MERV (minimum efficiency value) rating based on how effectively they capture particles of different sizes. Also note that thicker oven filters tend to last longer, providing greater filtration over time, so they usually cost more than 1 or 2 oven filters. A Honeywell oven filter will have the same filter replacement recommendations as standard filters. The filters are designed to trap dust and particulates suspended in the air as the air passes through the filter and into the furnace system. It is important to remember that when changing your furnace filter you should always check the size of your filter before purchasing a new one.
You may not have realized that the furnace filter needs to be changed because not all air conditioning systems need heating, ventilation, and air conditioning filters. We also offer filters for 5-inch ovens (16x25x5 or 20x25x), whole-house air filter brands, and filters for rigid cell ovens. So how often should you actually change your oven filter? It is recommended that you change your furnace filter at least once every 90 days or every three months. However, this depends on the thickness of the filter and other factors such as allergies or respiratory sensitivity. Thomas & Galbraith Heating, Cooling and Plumbing recommends changing filters less than 2 inches thick every 30 to 90 days.
Three- or 4-inch filters can last 6 to 9 months, and filters up to 6 inches thick can be replaced once a year. You can say that you need to change the one-inch filter in sixty days when in fact you have a four-inch multimedia filter that doesn't need to be changed yet.
