Replies

1. 
   calvin | Jan 23, 2014 04:10pm | #1

   mrd

   could you run through the scenario one more time-I'm unsure what it is you're looking for.

   There are wall registers that have a removable grille that houses a filter.  Is this what you're after?   What size?

1. 
   mrd999 | Jan 23, 2014 05:42pm | #2

   I'm adding an outdoor air intake to the system.  Looking for a vent hood for exterior sidewall application, with a replaceable filter accessible from the exterior.  Don't want to let the skeeters inside.  Something flanged for vinyl siding would be ideal, but as long as it's flashable it'll work.

   One of those filter grilles would work if I was on a porch wall/ceiling, but unfortunately the location is exposed.

1. 
   DanH | Jan 23, 2014 06:35pm | #3

   So do you need a real "air

   So do you need a real "air filter", or just a screen?

   Where will the duct end up on the other end?

1. 
   mrd999 | Jan 23, 2014 09:24pm | #5

   Air filter would be ideal, to keep pollen and dust from getting inside.  The duct is tapping into the return side of a heat pump coil.  Want to keep it clean.

2. 
   calvin | Jan 23, 2014 09:15pm | #4

   mrd

   Is this for an indoor combustion appliance like a fireplace/woodstove?  And why a filter?

   thanks.

1. 
   mrd999 | Jan 23, 2014 09:25pm | #6

   Heat pump; filter to keep out dust and pollen.

1. 
   DanH | Jan 23, 2014 09:35pm | #7

   So you don't draw return air from inside the structure??

2. 
   mrd999 | Jan 23, 2014 10:21pm | #8

   Currently, all of the return air comes from interior air.  The return duct has a filter grille (a hinged grille where the filter goes just behind it) accessible to the occupants, with a return trunk that runs to the blower/coil unit.

   I want to add an outdoor air line, which will tap into that return trunk.  The new line carrying outdoor air will intersect the trunk between the filter (at the grille) and the blower/coil.  Dirty coils are inefficient, and some occupants are sensitive to pollen, so I want to place a filter somewhere in that new line prior to its intersection with the trunk.

   The trunk is not easily accessible, and it would be preferable to replace the filter at the exterior wall, where the new air inlet goes.  Last resort would be an inline filter which likely wouldn't be changed at proper intervals due to poor access.

2. 
   mrd999 | Jan 23, 2014 11:24pm | #9

   Problem is, the other side of the filter would mean connecting the intake directly to the living space.

1. 
   DanH | Jan 24, 2014 06:52am | #10

   And the problem with that is??

2. 
   calvin | Jan 24, 2014 12:05pm | #11

   mrd

   you still have me confused.  If this is forced air heat, the return air should not be from the exterior of the dwelling .  Combustion air is a different story.

   Freshair makeup would be a Heat Recovery Ventilation type of operation.

   no?

   tho there was that heat pump operation in a house my daughter rented for a bit in Nashville........................it might have brought air in from the outside..........memory is too watered down for any detail.