Which pleated furnace filter is better from the same company, a 7 pleat or an 11 pleat?
Answer: I was unable to contact the person who asked and get some clarification so I will give a couple of answers.
When talking about pleats people are usually referring to pleats per inch of filter material. But a pleated filter wouldn’t have 7 or 11 pleats per inch, it would usually only have about 1 to 3 pleats per inch.
If the question was intended to be, which is better MERV 7 or MERV 11, then I would say the MERV 11 filter is better as far as efficiency is concerned.
If the question was intended to be about the number of pleats per inch I would say there shouldn’t be much of a difference. Usually, the higher the MERV rating a filter has the more pleats per inch there will. This is because more pleats per inch means there is more material in the filter overall. This is necessary to insure the filter doesn’t exceed the .1 inch static pressure drop that most manufacturers design their filters to meet.
Quality manufacturers aim for as little impact on air flow as possible when designing their filters. As the efficiency of the filter material increases so does air flow restriction. One method of compensating for this is to have more pleats per inch of filter. Another method is to use thicker filters and this allows for even more filter material to be used.
More pleats per inch also distributes the dust collected by the air filter over a larger area and therefore it can remain in the system longer before it must to be changed.