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samantha_fischer83

hvac vent help needed asap!

4 years ago

My not so detail oriented contractor just screwed a return vent over this hole they cut for our return…

Can someone recommend what we can do to make this better? They are coming today to do details and I’d like to have a plan but I’m stumped…

Comments (16)

  • 4 years ago

    I think he did? He said he’d have him come back today. I guess I just don’t know what to do to have this not look terrible..

  • 4 years ago
    last modified: 4 years ago

    Im definitely no pro, just a homeowner, so please excuse my lack of technical terms! i just peeked through our very similar return vent. The drywall cut is hidden inside the solid edges of the vent face. Directly behind the vent cover, there is an open metal box (again, fitting the shape/size of the vent), which then the round duct leaves from.

    heres my attempt at drawing this!


    Not sure if that drawing makes sense… it is from the perspective of looking along the wall cavity, at what you’d see behind the vent cover.

  • 4 years ago

    Exactly what A G said. There is no good reason to have your return opening smaller than the grill--it's just costing you return capacity.

  • 4 years ago

    You need a diffuser which hides the vent. Here is an example at Lowes.


    14-in x 14-in Step-down Steel Ceiling Diffuser in White https://www.lowes.com/pd/Accord-Ventilation-White-Steel-Ceiling-Diffuser-Rough-Opening-14-in-x-14-in-Actual-17-94-in-x-17-94-in/1003194980


  • 4 years ago

    One of the problems I see is that the passageway from the boot to the opening is unfinished. It may be too late to do it properly but return boots usually have sheet metal aprons or a frame to cover and close the sides in the transition into the boot. Here's an example.


    PS - Mike, I think the part you linked to is intended for a supply opening, not for a return.

  • 4 years ago

    Cut the ceiling drywall out if the box behind it is square, otherwise paint the drywall black behind the grill.

  • 4 years ago

    Oh thanks that’s an idea sktn77a

  • 4 years ago

    i don’t see why the diffuser would not work. I think it looks nicer. The black paint suggestion is a good idea.

  • 4 years ago

    The diffuser ring channels supply air out in a specific pattern. Wondering whether it would slow down return air intake at all.

  • 4 years ago

    Is this the only return vent? It seems small if it is. Is the filter in the attic? Is so do you have an easybway of going into the attic to change it when it is dirty?

  • PRO
    4 years ago

    This really should be a filtered return grill not just a grill.


    If you have a filter at the unit that is another way to do it, but after a year or two (maybe less) that cavity is going to be caked with dust, dirt -- even if you paint the ceiling part black then it will be black with caked dirt. Not a fix by any stretch of the imagination.


    You can tell a filtered grill from just a grill because the filtered grill will open up and there is room in that grill to properly hold the filter in place.


    If you put in a filtered return grill the existing hole should be squared up. I suspect they may not have attached a plenum either and are attempting to just rig a duct to this cut hole?


    I've seen too much, I should probably just look away.......


    I service the Katy, Texas area.

  • 4 years ago

    Austin Air-
    Can you have a filtered return as well as a filter on your furnace/indoor unit? We do have filters on the unit itself but it seems like a filter at that spot would be good

  • 4 years ago

    What a mess, is my only thought

  • 4 years ago
    last modified: 4 years ago

    In my experience (as a homeowner), filter-holding return grills are often used when HVAC equipment is located in an attic, a location not easily accessible to the homeowner should the filter be placed there.

    A filter box at the equipment, when it is accessible, is much more convenient. If that's what you have, Samantha, that's what your system was designed to have and be glad for it. You don't want to add another filter at the return grill, that will restrict airflow thus reducing the effectiveness of the system and that puts a strain on the blower motor. What you have is fine and easy to change, Leave it as is.

    Filters in ceiling return grills can be inconvenient. A friend of ours, a single woman approaching retirement age, has such a setup. Her ceilings are 10 feet high. She's uncomfortable climbing a ladder and so needs to call a handyman in twice a year to change her filters.

  • 4 years ago

    "Can you have a filtered return as well as a filter on your furnace/indoor unit? We do have filters on the unit itself but it seems like a filter at that spot would be good."

    Yes, you can, but it's a pain to change a filter if its in the ceiling. Also, 2 filters have more restriction to air return to your furnace and can potentially cause damage.

  • PRO
    4 years ago

    Austin Air-
    Can you have a filtered return as well as a filter on your furnace/indoor unit? We do have filters on the unit itself but it seems like a filter at that spot would be good


    There are many ways to filter HVAC, some designs will leave the return unfiltered and have a larger 4 or 5 inch media filter right before furnace.


    From there (where the return(s) are sized well it proposes options of incorporating a pre-filter. (cheap see thru filter) on the returns before the larger 4 or 5 inch wide media filter.


    I don't suggest you incorporate a two filter set up on your own. Because of the 2 filter restriction problem will cause more problems that that type of set up will cure.


    The problem with the 4 or 5 inch media filter at the furnace design is that the returns will become laden with dust in time. The dustier the home (typically more foot traffic, either people or pets) it won't take long for a clean return to become filthy. Dust contains dust mites. Small little creatures that feed on that dust.


    The whole reason to put a filter at the return entry is to prevent that, capture the dust at the filter change monthly. The 4 or 5 inch media filter typically you get away with 1 or 2 filter changes per year.


    Most returns are undersized. So when you place a filter at the filter return grill and then another at the furnace the HVAC becomes choked for air. This ramps up static pressure, utility bill costs, makes the AC & furnace have to work much harder than what they would have to otherwise.


    AC really needs 350-400 CFM (cubic foot per minute per ton) --- if you have a 5 ton AC that's around 2000 CFM. If you only provide 1600, the 5 ton is a 4 ton... yet you are paying for 5 tons as most are single speed systems.


    The reason why most returns are undersized is mostly due to cost / cutting corners OR possibly over sizing equipment. This is a part of design as much as everything else.


    An easy way to see if your return is too small is with the system running in AC mode place your filter in the return, the filter should not be sucked in... should be loose fit with only a slight pressure draw into the return grill.


    An inward bulge of the filter as it becomes filled with dust is an indication to change it, not a function of how it should be the minute you put a clean filter in the return grill.