When it comes to furnace filters, the old adage “you get what you pay for” is true. Thicker filters, known as multimedia filters, are usually 4 to 5 inches thick compared to the ubiquitous 1-inch filters that can even be purchased at grocery stores. But does thickness really matter when it comes to furnace filters?The short answer is yes. Thicker air filters tend to last longer because they have more square feet to capture and retain air particles.
To put that in perspective, a 1-inch air filter may need to be changed every month, while a 4-inch air filter could last up to six months. Virtually any HVAC professional will tell you that thicker filters work better than common 1-inch oven filters. A 4-inch thick filter will have more holes than a 1-inch filter. So it will be easier for air to pass through and become less restrictive. Poorly installed one-inch filters whereby air circulates around the frame (even causing the frame to bend and deform) are very common.
But does that mean that 1-inch filters aren't good? Let's dive into the details and find the right solution for your oven. If you put several 1-inch filters together, it's similar to putting together 5 coffee filters and trying to make a cup of coffee, it just doesn't work. Therefore, if it is absolutely necessary to install these thicker filters on a return grille, I recommend that you close the return duct tightly and be airtight. Standard oven filter sizes are 1 inch or 5 inch thick. However, with most HVAC systems, you should be able to modernize a media filter cabinet, either under the oven or on the side. The nominal size of an oven filter is a rounded number that is best suited to the commercialization of standard filters.
It is a known fact that the standard dimensions of oven filters (length and width) have nothing to do with their efficiency. For those who don't know or just need a reminder, oven filters remove dust, dirt, pollen, allergens, bacteria and other air pollutants from your home air, improving indoor air quality for you and your family. If improving air quality is a priority for you, filter depth doesn't matter as much as the MERV. Since you'll be replacing 1-inch filters with a MERV height more frequently than 4-inch filters (see the maintenance section above), you could save money with a 4-inch filter, depending on the MERV you get. Pay attention to what matters most to you and you'll find out which filter is right for you. A dirty filter can cause the air conditioner to stop cooling, reduce efficiency, or cause the air conditioner to freeze. In conclusion, if you're looking for an effective furnace filter that will last longer and provide better air quality for your home, then a 4-inch filter is your best bet.
Paying attention to changes in your home (for example, a building) and in your city (a nearby building or a large amount of pollution) will also help you decide when to replace the filter.