I'm wondering if a single room "ERV" is an option. The one below looks damn near perfect - I could install myself, and it's not crazy expensive:
To repeat what I said in my last post, I'm pretty sure you'd have to put the unit in front of the air handler unit. I don't think you can just run it into your room as it won't be pumping conditioned air back into your space. PLUS, this will eat up a lot more room than necessary. If you tap into your system AND make more holes in your walls for the ERV, you'd need a total of 8 silencer boxes. That is just unnecessary space and headache dealing with silencer boxes.
It's also supposed to be very quiet, but maybe I would still need to do a silencer box on it somehow?
The silencer boxes aren't there attenuate the sound of the unit itself. It's there to maintain the isolation of your room.
When I finally post my layout this will make more sense, but there is ductwork coming off the furnace/AC that goes upstairs, and our plan would be to tap off of that, so that we don't have to run much more ductwork.
This won't work. That duct work is sized specifically to provide the correct amount of air to your "upstairs". You can't just tap off a branch like that. If you did want to tap off of a branch, you'd have to upsize the branch between your tap and the air handler itself to accommodate the extra air flow. So in short, you'd have to rip out what exists up until your tap, and redo it the correct size. Now, in order to determine the needed size, you'd have to first figure out exactly how they designed the system. There are several different design methods and you'd have to use the method they did.
Oh man. That app is $130
The app I got is the HVAC ASHRAE Duct Fitting Database iOS App. It sells for $15.
OK, I'm a little confused here. So is it 2 large silencers each for the intake and return? One on each leaf of the wall? I guess I was thinking it could be one large silencer per vent, but I'll do whatever the correct thing to do is.
Think of it this way: You have a sheet of drywall. It is providing you with x amount of
transmission loss. You cut a hole in it. You've now lost that isolation. To "patch the hole" you need to obtain the same level of isolation you had before. Problem is, you need air to still come and go all while stopping the sound from propagating in and out of your room! THAT is where the silencer box comes into play. The silencer box will provide x amount of
insertion loss, matching your old amount of
transmission loss.
So, to put this into practice, let's look at your room. If you build a room in a room, you have drywall (on outer leaf), insulation, then drywall (on inner leaf). That is TWO different masses of drywall you're cutting holes in. That means you need a silencer box on each one.
You have both supply and return holes in your walls. So, that means you need four silencer boxes. The most ideal way to design your room is to have the silencer boxes live between your inner and outer leaves.
I may be overly optimistic, but I think I can figure out a way to get pretty large silencers without giving up too much space, by putting them in dead zones or "outside" the room, basically taking up space from a planned non-studio storage area or the foyer. Again, this will make more sense as my layout develops. But by and large, if I don't feel confident in my pressure calculations, is it a reasonable safeguard to build very large silencers with huge cross sectional areas to minimize pressure problems?
Remember, for your inner leaf silencer boxes, they either have to live between your leaves, or inside your room. These are the problematic ones. Draw out one on paper and check out how large it is. Remember, they need at least 3 baffles and it has to zig zag back and forth at twice the cross sectional area as it's inlet/outlet. If you have the quite standard 2 layers of 5/8" drywall for your leaves, the smallest you can make the structure of your silencer would be 1" thick MDF. You need at least 1" thick duct liner inside of the silencer. So, as an example:
- inlet = 160 CFM
- based on a 0.1 friction rate, your inlet duct size would need to be an 8" round duct
- 8" round duct = 50.27 square inch cross sectional area
- cross sectional area of your silencer box = twice the inlet. 50.27 sq in X 2 = 100.53 sq inch.
- so as an example, the inside dimensions of your box could be a 10"x10" path.
if your 10" dimension can be assigned to the value "x":
The needed inside dimension width of your box = 2x+4 = 2 x 10 + 4 = 24".
Then add the 1" MDF and 1" duct liner on each side of that: 1 + 1 + 24 + 1 + 1 = 28" wide
- the height of the box is as simple as adding the MDF and duct liner to your 10" height. So that = 14"
- the outer length of the box would be:
(4x) + 11.5" = 4 x 10 + 11.5" = 51.5"
The 11.5" I derived from:
2" for the MDF and duct liner, then x as above, then 2.5" for 2" duct liner plus 0.5" of MDF for the baffle, then x, then the 2.5 again for the second baffle, then x, then 2.5 again for the third baffle, then x again, then 2" for the other side MDF and duct liner.
SO the dimensions of each silencer box would be:
W = 28" (note, this is over 2 feet wide)
H = 14" (note, this is over 1 foot wide)
L = 51.5" (note, this is over 4 feet long)
FOUR of those. That's a lot of space! If you want to for a nice low static pressure and air velocity, you could build them like Stuart does and Y split them. So, he basically builds 1 box long box that splits in the middle and off of this Y branch, he puts one of these big boxes (like I just mentioned above) off each side! This allows him to have half the static pressure, twice the cross sectional area, and half the air velocity. It's an awesome design, if you can fit them!
Awesome, thanks! I will give that a shot when I have some time.
I have a feeling that once you run these figures, you'll realize that your air handler is not designed to provide enough BTU. It's crazy, but as far as I've learned, HVAC dorks don't even calculate the basement in their cooling loads. And they aren't going to put in an oversized unit for several reasons, the biggest one being cost!
Gotcha. I guess my point here, and with some of my other comments and issues, is that I will not be in this room 90%+ of the time, and it's definitely an option to leave the doors open to the rest of the basement while I'm not there. So everything I'm doing will be to make it safe and comfortable for while I'm in there. I feel like if I'm keeping temperature and humidity at appropriate levels while I'm not in there, the equipment will be happy and any moisture/smell/etc. issues will be minimized, because it won't be an airtight space most of the time. Is that a reasonable thing to think?
Unless you're able to fully recirculate the air in your room (opening a door does not circulate air) 6 times per hour, then you're not following the ASHRAE guidelines for your room.
If it's under let's say $1,500 or so installed, I could probably swing that.
I'm not sure what things cost where you live, but an HRV costs that without installation here. It's easy enough to do yourself though.
I know the mini-split is an attractive option, but unless all else fails, I don't think it's in the cards for me. Contractor quoted about $3,500, give or take, and I think that is just out of my price range for this part of the build.
Like all of us, you might just have to save some pay cheques for a while and get your studying and design done. By the time your design is 100% complete, you could have that extra $3500 in your build out budget
Greg
Think about that for a second: The studio is basically a hermetically sealed box: totally air-tight. And you are saying that there will just one duct coming in, with nothing going out.... Think it through... 
That's the situation: the duct is basically like a straw that COULD send air into your room, but since your room is a tightly sealed box, the air can't go in! It has no place to go. You MUST have a return duct! This is very, very basic, and I'm really surprised that your HVAC expert did not figure this out for himself... If there is no return duct, then there is no place for air to get out of the room, so it is impossible to put air into the room...
Yup...
I tried Not sure if I succeeded.... 
Thank you! Swimming may be optimistic...but at least I have this site for a flotation device, to torture this metaphor