New Design

[gullfo]

so - dealing with a single leaf into the attenuator on the room side - a metal elbow off the flex ducts or short flex duct from mains to elbow or straight - depending on clearance. then on the room side the attenuators in the soffit (or if you're doing a drop ceiling). or if you have room, the attenuators can be in the air space above the boundary. then route the in-room ducts via soffits / drop ceiling etc.

in this example the depth of the take-offs (to connect things neatly) is exaggerated but the idea is one on either side of the mass layer to enable something to attach to. since both are connected to the mass layer, a metal passthrough if needed is ok, but the connection to the boundary must be flex duct (or equiv) to keep it decoupled from main hvac ducts.

[Soundman2020]

Source of the post There seems to be no edit button on earlier posts I made , Is there a way to edit ? Am I missing something?

You can only edit your post for a limited time after you send it. I think it is an hour, but not sure. We had to implement that to prevent spammers from misusing the system by first posting something valid, then waiting a few days and modifying it with their spam.
I'll see if I can find that setting again, and allow a bit more time, as we seem to have spammers mostly under control for now... (at least until AI figures out how to bypass the safeguards....)

- Stuart -

(PS- Found the setting, and changed it to one day. So you can edit your post for up to 24 hours now.)

[Soundman2020]

Source of the post

Source of the post There seems to be no edit button on earlier posts I made , Is there a way to edit ? Am I missing something?

You can only edit your post for a limited time after you send it. I think it is an hour, but not sure. We had to implement that to prevent spammers from misusing the system by first posting something valid, then waiting a few days and modifying it with their spam.
I'll see if I can find that setting again, and allow a bit more time, as we seem to have spammers mostly under control for now... (at least until AI figures out how to bypass the safeguards....)

- Stuart -

(PS- Found the setting, and changed it to one day. So you can edit your posts for up to 24 hours now.)

[1970428scj]

I would like to edit my photos in a post in this thread to fix some of them?

[eightamrock]

Source of the post so - dealing with a single leaf into the attenuator on the room side - a metal elbow off the flex ducts or short flex duct from mains to elbow or straight - depending on clearance. then on the room side the attenuators in the soffit (or if you're doing a drop ceiling). or if you have room, the attenuators can be in the air space above the boundary. then route the in-room ducts via soffits / drop ceiling etc.

in this example the depth of the take-offs (to connect things neatly) is exaggerated but the idea is one on either side of the mass layer to enable something to attach to. since both are connected to the mass layer, a metal passthrough if needed is ok, but the connection to the boundary must be flex duct (or equiv) to keep it decoupled from main hvac ducts.

Hey Glenn, I assume a lot of this doesnt apply when using mini-splits with the head in the room. For the fresh air from my ERV, would I just use the left most design in the ceiling air cavity between the joists and dump it out right above the head and have a similarly designed return on the other side of the room?

I know I am over simplifying all this, but the head should mix the fresh air and room air that its conditioning so that makes sense to have it dumping right over top. However I don't know if the return to the erv should be spread out or not?

[gullfo]

regardless of just air exchange or full air conditioning, the units would be the same (except you would have them size accordingly)

[eightamrock]

regardless of just air exchange or full air conditioning, the units would be the same (except you would have them size accordingly)

Right so thats what I meant. The ERV does 157 CFM and uses a 6" duct connection. So I would design it for 2x the duct size? 12"x12" path through the baffle?

[gullfo]

that would be good, the effective speed will be around 150fpm or 2.5fps - which if you can expand again in the soffit, you would be in good shape for low velocity.

[1970428scj]

Got a quote for baffle box lining from Acoustical surfaces $700 for MT and $800 in ship wow. Is there a supplier on the west coast you have used? This is just crazy

[gullfo]

MT?

[1970428scj]

material, sorry

[Soundman2020]

Got a quote for baffle box lining from Acoustical surfaces $700 for MT and $800 in ship wow.

That does sound rather steep! How many square meters would you get for that prices? Duct liner isn't cheap, but certainly not THAT expensive, unless you are ordering a rather large amount.

There are alternatives. Google "HVAC duct liner", and see what you come up with in your area. Post the details of what's available here on the forum, and we'll help you choose a good option.

- Stuart -