I have a Lennox heat pump which has an air handler with a Lennox X7935 Carbon Clean Healthy Climate MERV 16 Filter installed. These filters are like $105 per at least. When we purchased this whole system from Horizon, they stated we'd only ever need to change a filter once a year. One year later when we had our maitanance, they asked if we ever changed out filter, to which we responded no. Turns out, it's supposed to be replaced every month or couple of months.
I see that there a lot of aftermarket filters out there with the exact same dimensions, but a slightly lower MERV rating. My question is, should I stick to the factor installed filter, or is it ok to go with an aftermarket brand? Some of the ones I'm seeing are as low as $55 for two, vs. $105 for one.
Other than less filtration, is there any other risks I should be concerned about? Would this cause damage to my air handler or other components?