It is not recommended to stack several smaller air filters on top of each other in order to fit them into a larger air controller. Installing several 1-inch air filters in a 2-slot, for example, can cause costly damage to the air conditioning unit, since residential ovens are not equipped to withstand this level of air flow restriction. Do not stack 2 to 1 pleated filters either, as this will increase static and affect system performance. Why not use a 2-fold filter instead? As for stacking two disposable filters, it would probably be fine for the system, but it seems a bit unnecessary. By stacking 1-inch filters, multiple layers are created for air to pass through.
With media filters, however, it's still a single filter layer, only it has much more surface area. In some cases, the air controller's intake grilles or ventilation grilles have a filter depth greater than one inch. Because 1-inch air filters are the most common, some homeowners may think it's OK to place 1-inch air filters to fit in a 2-, 3-, or 4-inch air filter slot. This is not recommended. Depending on the size of your home, you may have more or fewer entry holes, but in most homes, the central air system has two intake openings covered with an air filter. Having multiple return grilles solves this problem, but it also requires air filters in each vent to properly filter the air and prevent particles from entering the fan motor.
If you live in a large enough house, condo, or apartment, you'll have several return ducts to effectively recirculate air throughout the house; after all, no one likes poorly ventilated rooms and irregular temperatures. If your old air filter doesn't have the measurements printed on its side, you can measure the filter. If your boiler has an air filter in the return vent, changing the filter is easy since you can do it from inside your home. Thicker oven filters, known as media filters, almost always work better than cheaper one-inch filters. This ensures that you won't restrict the air flow through the boiler too much and that everything is running smoothly.
It's questionable whether it works the same way as a 2- or 4-inch air filter in terms of filtration effectiveness when working with your central air system. Basically, when you're taking measurements of an air filter, you just need to round it up to the nearest inch to find the dimensions of the filter you need to buy. Please note that the actual size of the air filter will be smaller than the nominal size of the air filter. 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. These 4-inch multimedia filters can have between 20 and 30 feet of surface area with their pleated (accordion) filter material. And the first thing I always checked was the oven filter because a clogged one-inch filter gets dirty very easily. And you'll have a more comfortable home environment because there's more airflow and it'll heat your target temperature more easily.
