Filter confusion

11 years ago

Filter Sizes:

I'm baffled by the range of choices for furnace filters.

A new furnace that I'm having installed will have a custom built 20x20x4" media cabinet. But looking around, I'm seeing that the 4" filters are actually undercut to around 3 3/4"...which I assume will fit in my cabinet.

To make matters even more confusing, there are some "so called" 4" filters that are really 4 3/16" to 4 3/8" that evidently are for the Honeywell cabinets. Not sure though. Where I'm really confused is that the 4" undercut filters seem to be pretty generic and not the best quality, again I think. Is the 3 3/4" size even standard and can be picked up at a local store ??

Merv Ratings:

I'd like a better Merv rated 4" filter....say around a Merv 10-13, but I'm worried about 2 things:

1. Air resistance. Will it even work, or will it slowly destroy the furnace ?

2. Is it realistic to change a Merv 10-13 filter every 6 months ?

If not, then perhaps I should stick with the cheaper Merv 8's and change them more often ????

This post was edited by audiomixer on Thu, Feb 7, 13 at 22:19

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Comments (5)

tigerdunes
11 years ago
Here is my post in your other thread. And BTW, you should keep your posts in the same thread.

Being a Trane system, I would want their Perfect Fit Media cabinet. The name alone explains why. The cabinet fits to the furnace like a hand fits a glove. It has gaskets that seal the door nicely. Very easy to open and close when replacing filters. Filters while proprietary size can be purchased at Internet filter houses, both OEM and generics.

Without knowing more details about the reason for the custom cabinet, I think this is a stupid idea when Trane has a very nice, solid heavy duty cabinet that is made to fit their furnace. Therefore the name Perfect Fit
media cabinet. BTW, the filters for the Trane cabinet are a nominal 5" depth.

You are over thinking the MERV question. MERV 8-10 is the sweet spot
for most homeowners and not restrictive.

IMO
audiomixer
Original Author
11 years ago
Tiger, the info......in both forums. I appreciate it. I know you like the Trane filter box, but from what I see it's about $500 or more extra. That may be too much for me. I will try to look at the custom one.

I don't necessarily agree about the merv rating. There is a big difference between say an 8 and 11 or 13. But where I was concerned was air flow and how often you should really change a filter.
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tigerdunes
11 years ago
I always hate to see a homeowner take a shortcut especially on a nice system. Look at an AprilAire or Honeywell model. Trane though is the way to go if you want a HD cabinet that fits perfectly to the return end of the furnace. No transition needed from the cabinet to the furnace. It is tight. Why? Because it is made to fit.

IMO
mike_home
11 years ago
You would change a MERV 8 filter less often than an 11 or 13 since it capturing less particles. Most systems have high static pressure so I recommend using the MERV 8.

A 4 inch filter should go a year between replacements. But the time is a function of how much you use your HVAC.
audiomixer
Original Author
11 years ago
>>>No transition needed from the cabinet to the furnace. It is tight. Why? Because it is made to fit.
IMO

Same with this one if it's done right.....we shall see.