Hi - great product however the overall height of the filter is just under (<1/4") the Honeywell filter equivalent. This creates a gap at the top of the filter that allows unfiltered air to pass by. I had to place a filler to close the gap at the top. Future filters should have an extra flap or piece of material to fill that gap.
Filters don't appear to be as good quality as what I have purchased elsewhere in the past. Not as sturdy frame or as many pleats as what I have used before. Just started using them so not sure how well they work yet. Hpwever, they were less expensive so possibly got what I paid for.
I have an oddball dimension because my dimensions are accurate, versus the filters at the store which are usually larger than their actual label. Recently they stopped stocking that size and they don't even order them anymore. Which left me in a bind, I'm glad I found Fiilterby, I was surprised at how many dimensions were available, I will be going back 1st long as I have this furnace and I've already recommended them to a couple of people verbally.
Using the filters for a project, not our heater. They are helping us with smoke and allergies by super cleaning our indoor air. We are getting ready to order the filters for our heater next! See you again soon!
The filter was actually only about 3 1/2 inches deep so air is going to go through the path of least resistance whicih is going around the filter. The filter description said it was 4 inches but it is not. Your concept is a good one but you need to have quality filters.