Honeywell FC40R filters - help?

ceburyJune 23, 2012

I've read the various posts on using the 4" MERV8 (or less) filters. I'm about to purchase them, but I have the cabinet that accepts 1" filters, but it does the metal tabs that can be bent/removed and hold a 4" filter.

However, Honeywell directions shows needing "7 inches total for a 4" filter". How important is having the extra 3 inches of space above the filter?

Thank you for reporting this comment. Undo
mike_home

It's hard to say how critial the space is above the filter. You may get a whistling sound as the air tries to rush through the constricted opening.

Have you considered using a 2 inch filter?

    Bookmark   June 24, 2012 at 12:27PM
Thank you for reporting this comment. Undo
cebury

If whistling sound is the only downside (ie. not an extreme difference in strain on the blower) then I'll just order one of each size and see what works best. I assume the 2" will just need replacement more often.

Thanks

    Bookmark   June 25, 2012 at 7:24PM
Thank you for reporting this comment. Undo
cebury

UPDATE: I found another site explaining in more detail why I should avoid the 4/5" filter if I don't have the required 7" total space above the grill (really = 2 5/8" minimum above the filter before the flex duct starts).
http://hvac-talk.com/vbb/showthread.php?t=964082

The OP there has *exactly* my scenario with same filter box measurements and space available.

I guess I'll go with the 2" for now: I should've had them enlarge that box when I had them change out the ducting.

I was originally recommended to use the Honeywell F40CR 4" filters by ZippyHvac in the thread here . There appears widespread acceptance that these 4/5" filters are excellent, better than the 1" Filtretes, at least for their primary purpose: protection of the unit's coils, as they can collect a lot more particles w/out requiring often change-outs and do so with less increase of static pressure.

    Bookmark   June 29, 2012 at 1:36PM
Thank you for reporting this comment. Undo
mike_home

The 3M filtrete filters do a good job of filtering but are very restrictive. You are better off with a cheaper filter.

The 2 inch filter is still am improvement over the 1 inch. Even a good 1 inch filter is OK if you check and replace it on a regular basis.

    Bookmark   June 30, 2012 at 10:16AM
Sign Up to comment
More Discussions
New Mini Split Designs for 2015
I, and I am sure others, would love to hear what is...
josey11
Navian condensing combi, good or bad?
Hi, I am looking into converting from oil to gas and...
rickyk22
Problems with HVAC in 1958 Cape Cod
I've been reading the blogs here and hope that the...
ginaff58
Insulating floor on my raised home in Louisiana.
We recently installed solar panels on our home. We...
ktyler1320
I Like the Forum Changes
IMO; this new forum setup is an improvement...
udarrell
© 2015 Houzz Inc. Houzz® The new way to design your home™