On Jan 6, 1:01*pm, 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.

"the AC guy says that the duct work is not that hard to do."

What did the AC guy say about the benefits of adding another grill?