CFM Filters

[zekor]

I do not do this proffesionally. Last furnace installed by the same people. I felt the 100K BTU furnace had a slightly undersized filter 16 X 20. I was able to use the orginal large ductwork and cut a slot so I could use the orginal 30 X 20 filter. My new furnace just installed yeaterday. I spoke with the installer requesting a larger filter, said OK. The actual installes began making a 16 X 20 slot, and after some small talk I agreed to go with it. I didn't feel like going through an argument period. He said the slot is 16 X 20 and a bigger filter does not do anything more. When I go to the store all standard filters are the same price. For me, a larger filer has less restriction, last longer, and you can go with a better more restrictive air filter, like a 3M type. Maybe I can figure out later how to remidy the situation. Whos right?

GS

[zekor]

I have experimented and have used the 3M Filtrite things for some time. I even wash them. Unfortunately the cardboard is hard to handle. If only they would put them in plastic holders. They wash up quite well, and filter cigarette smoke fairly well compared to other similar types. The media is sometimes found separate, used in window airconditioners. thats easy to wash and reuse. I usually have to shop at The Home Depot, and being the store is so huge, never have space to sell 30 X 20 filters. I have a really hard time finding carbon filter elements anywhere. The 3M 20 X 30 Filtrite is a really good buy, and the same price as the 16 X 20. What a ripoff. If only the furnace people would have space for two series filters, so a loose prefilter could be used in front of the high density filter.

GS

[Danny G.]

I try to have one square foot per 400 cfm or so of filter area when I build filter racks in residential / commercial HVAC ductwork.

Personally I would just buy a case of the standard 16x20x1 10% filters. They actually filter better dirty anyway. Another option would be a pleated filter. (more surface area)

Your HVAC salesman might have included a larger filter rack in the price. If your duct work is rectangular and there is space to cut in a bigger filter rack they might install one to make you happy.

GL Dan