On Jan 6, 9:38*pm, mcp6453 wrote:
Tony Hwang wrote:
mcp6453 wrote:
The return air duct on my upstairs heat pump (the same one with the
thermostat issue also discussed here) sucks air through the filter at
such a high velocity that the filter is not of much value. (It also
pulls the bathroom door up against it, if I'm not careful.) The
present grill is 20x25x1. I cannot find a much larger one. Is there
any reason that I could not or should not add a second 20x25x1 above
it? There is room on the wall, and the AC guy says that the duct work
is not that hard to do.
Hi,
Some filters are air flow restrictive for better filtering. Tried
different kind of filter?

The higher efficiency filters make too much noise because the air flow is so high.

Thats bs, I have 4", its no quieter without the filter I have