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08-17-2012, 02:39 PM #1
Any benefit to adding 5-inch media filter when new system is installed?
I've been using 3M Filtrete Filters to help with my dust/pollen sensitivity, either their MPR 1000 (Merv 11) or MPR 1500 (Merv 12), depending on what's on sale at BJ's or Sam's Club. Current system is 3.5 ton Rheem, 12 years old, struggling to maintain t-stat temps since the condenser bottom rusted and fell out and the coil fins have extensive corrosion. I'm looking into replacing the system with either an inexpensive 3.5 ton single compressor system, or going with the top of the line Trane XL20i.... 3 or 4 ton depending on Manual J load calc.
My question is this: Is there any benefit to adding a 5-inch media filter to the a/h?
One quote I received offers a "free" 5-inch media filter as part of the Trane installation. The extra 7 inches required to install the filter cabinet will require lowering the stand that my a/h sits on, which may require patching drywall or adding 2x4's or some such to repair the wall above the new, lower a/h stand. Without the media filter cabinet, there's enough space for the new a/h without changing the stand. This contractor's quote included the Trane 900 t-stat. I've since seen the Trane 950 t-stat and it's AMAZING to a geek like me! I'm thinking about asking if he'd consider dropping the "free" media filter and including the 950 t-stat instead.
Besides, if I use the media filter, I suppose I'd have to change it every so often and I understand replacement filters are quite expensive compared to the paper filters.
What do you all think?
08-17-2012, 03:26 PM #2
A 5" pleated filter is much better than any 1" filter, especially the so called "high efficiency" ones for a couple of reasons.
For one, the 5" filter is way better for the overall operation of your entire HVAC system because it will not restrict airflow the way a 1" filter will do. At the same time, because of how much more surface area there is, a 5" filter will capture more airbourne contaminants due to a slower air flow rate across the filter.
Just make sure the contractor has a good air seal around the perimeter of the filter, the filter has a well sealed door/panel over it and that there are absolutely no openings whatsoever between the filter and the system blower wheel. That means screw holes, connections....anywhere that any amount of air can enter the system without being filtered.Government is a disease......masquerading as its own cureEcclesiastes 10:2 NIV
08-17-2012, 03:26 PM #3
There is more surface area on the filters so they help with static pressure issues. That also means they should take longer to plug up, I personally would take the filter.
08-17-2012, 03:27 PM #4
I guess roboteq hit enter first lol
08-17-2012, 03:29 PM #5
If duct is not sized properly for a 3m 1" filter or any restrictive filter for that matter it raises the blood pressure of the entire system (ESP!!!!) can cause harm to entire system. The 5" filters require less frequent changes due to the surface area of the media usually only once or twice a year.
08-17-2012, 03:40 PM #6
Wouldn't the planned 2 filter grill returns obviate the need for the media filter? They'll remain filtered regardless... would that be a problem?
08-17-2012, 03:46 PM #7
08-17-2012, 03:49 PM #8
08-17-2012, 03:54 PM #9
i agree, i would ask if instead of the filter at the furnace to put two 5" filters in the filter grilles themselves.
08-17-2012, 04:09 PM #10
Filters in filter grilles need to be larger than do filters located directly onto the unit due to the static pressure of the ducting between the filter grill and the blower section. There is also a reduction of free air area with the filter grill louvers. As long as there is enough free area of filter grill and all air passages from the filter grills and the blower section are completely sealed, filter grills are fine.
No matter what, 5" filtes are going to be much better than 1" filters. If you use 1" filters, it is best to use the least expensive fiberglass filters and make sure there is a good air seal around them.Government is a disease......masquerading as its own cureEcclesiastes 10:2 NIV
08-17-2012, 04:09 PM #11
Last edited by Florida Joy; 08-17-2012 at 04:19 PM. Reason: spelling
08-17-2012, 05:12 PM #12
08-17-2012, 05:44 PM #13
So.... I've decided against the "free" 5-inch media filter and the 7-inch Trane cabinet that it slides into.