When it comes to oven filters, size does matter. If your system only fits a 1 or 2 inch filter, a high MERV rating could be detrimental. A 1-inch filter with less surface space will clog up quickly and need to be replaced more often than a coarser filter. All forced air ovens use some type of filter, where it forces air through the filter before entering the main body of the system, and most oven and air conditioning systems share a filter.
Many use 1-inch filters, but some use filters up to 5 inches thick. There is no difference between 1 and 5 filters with the same Merv rating, in terms of the size of the filtered particles. There is a difference in static pressure between the two. The 5 filter has more physical holes for air to pass through, making it easier to pass through.
Larger filters will make the system less restrictive and wear down the fan motor less, which will extend the life of the equipment. More airflow actually puts more load on the blower motor, even in a small residential oven. Lock the door switch, turn the door back on, place an amplifier clamp around one of the power cables going into the oven, turn on the fan and observe the consumption of the amplifier. Now, with the door switch still locked, remove the fan door so that the fan can draw air directly into it.
Watch your amplifier go off. Many of us already know that regularly changing our air filters every 1-3 months gives our home cleaner and healthier air. But have you ever thought about switching to a larger air filter, such as a thicker 5-inch oven filter? After all, most homes have central HVAC systems that can accommodate large air filters. Replacing your standard one-inch air filter with a 5-inch pleated filter can improve the air quality inside your home.
This is because larger air filters have higher MERV ratings, leading to better filtration of contaminants and allergens. Meanwhile, the use of a 5-inch MERV 13 air filter has a larger surface area, leading to a high dust holding capacity. The larger surface area allows more air to pass through the filter, while effectively blocking all those harmful particles. Most 5 inch filters can work perfectly for 6 months to a year after installation.
So you don't have to change them as often as smaller filters require (i.e. 1 to 3 months). We have taken this particular question to break it down with an elaborate answer. For example, we have put a comparison of 4 inch vs 1 inch oven filters.
But in a broad sense, it's a comparison of “thin filter versus coarse-grained filter”. It filters a high percentage of particles, is not too expensive and does not reduce the efficiency of your system. Having a properly functioning filter will go a long way in reducing allergic reactions in your home (source). Your oven filter has a big job ahead of it, as it filters out all the dust and debris that get between the oven, the air ducts and, finally, your lungs.
Disposable fiberglass filters are incredibly inexpensive, but are often not as high quality as other options. Now that you know that size does matter when it comes to oven filters, it is important to talk about standard oven filter sizes in terms of nominal and actual size. Be sure to insert the new filter in the correct direction, as sliding it backwards could block airflow in your unit. When too many particles are trapped in the filter, it is more difficult for the system to push air through it.
If you need a high merv filter for air purity due to respiratory problems, buy an external air purifying device. If you have an old unit, not changing the filter often enough can cause enough damage to require you to purchase a completely new oven. As mentioned above, small filters with high MERV ratings can quickly prevent airflow when they get dirty. Someone with a passion for do-it-yourself projects might suggest making a frame to hold a 1-inch filter in place.
The clean and clear end result is that size does matter when it comes to oven filters - as long as it's thickness - as this will determine how well your system works and how long your equipment lasts. My house came with a Lennox G60UH (X) natural gas forced air oven and it has a filter box that carries 5 filters, specifically this type of filter - type X6670.