I just moved into a new house with a Trane Air handler (model TWE065E13FB) in the crawlsapce. I went to replace the filter as this was suggested maintenance and I found that there isn't a filter in the slot. Should I install a filter? If so what kind of filter? Looking online it seems that a 20x25x1 filter is the correct size.
http://www.jonesairconditioning.com/trane-filter-size-guide.html
The manual for the unit indicates the filter surface area (sq.ft.) should equal to CFM/300 for low flow and CFM/500 for high flow. I have 1600 CFM with a 4 ton heat pump (400 CFM/ton). If I use the high flow this gives 3.2 sq.ft., about a 20×25" filter. Is this the correct way to do this calculation. I can't see the filter slot accepting different sizes of filters without modification.
I'm not particularly sensitive to dust or allergens and on my return air vents I just use the basic Rheem/home depot pleated filter (20x20x1). Would a similiar filter be suitable for the air handler?
Best Answer
You should only have one filter installed for the system, so if the return with the filter leads to the air handler, then you're already covered, and don't need a filter in the air handler too. In fact putting a second filter in could be bad for your system, and could even cause your blower motor to fail because restricting the air flow even a little will slightly increase the load on the motor. Is that likely? No. But there's no extra benefit from having an extra filter, so why risk it?