Studio Build: Garage Conversion in Los Angeles

[Jag94]

Hey Starlight,

I don't have anywhere to put a bigger unit. The garage is detached, and there are no rooms or areas I can install this outside the room. That was the main reason for looking for a unit that could be installed inside the room.

I have not purchased the unit yet, but I just can't figure out how I can make an exterior unit work.

I understand the concept. The ducts bringing the air in from outside, and pushing the air outside (through the exterior frame) would be spaced far enough apart. That isn't an issue. But I do understand your concern with how the air is brought into the room, and sucked out of the room because the vents on the unit are so close together. I honestly don't think it's that big of a deal because the room is quite small. We're talking ~210 sq feet/~1700 cubic feet. The manufacturer says the unit can provide ventilation for a room up to 1200 sq ft. This unit probably isn't the BEST solution, but I think it could still provide adequate ventilation for my purposes.

[SoWhat]

Greetings jag,

I honestly don't think it's that big of a deal because the room is quite small. We're talking ~210 sq feet/~1700 cubic feet. The manufacturer says the unit can provide ventilation for a room up to 1200 sq ft.

I will let Starlight correct me if I'm wrong, but the issue here is not the capacity of the unit, but rather whether or not it will function properly. Remember, you are trying to exchange the air, and if the "new" air is simply dropped in and sucked right back out, you're not really exchanging it. I fear you might wind up with very stale air (read: too much CO2) opposite of where the unit is.

All the best,

Paul

[Jag94]

Hey SoWhat,

Yeah, that's what I assume Starlights concern is as well. But I feel like the unit is designed that way specifically for a small room. My room is significantly smaller than what their specs say the maximum size of the room should be, so i want to think the way the vents are designed, it is to make sure fresh air isn't being immediately sucked back out. If it happens in my room, it would happen in every room it's installed in, making it worthless for any application, no?

[Starlight]

My understanding has been that you have got a little bit stuck on the ventilator you have chosen, which is capable of moving enough air for your room but, in my opinion, is less than ideal. The one I pointed you two is 12" longer, pretty much the same width and height, and would be better suited to your situation, as Paul picked up on, above.

Jag94, I have no desire to push you where you don't want to go so I will not mention this again. I would urge you to look further into the possibilities of ventilators so that you feel confident in your ultimate choice.

Source of the postIf it happens in my room, it would happen in every room it's installed in, making it worthless for any application, no?

That is what concerns me about this particular machine, that it would be less than ideal in pretty much any application.

[SoWhat]

Greetings jag,

If it happens in my room, it would happen in every room it's installed in, making it worthless for any application, no?

Not really. Typically, and as shown in Starlight's HVAC plan (post #15), ducting (often exposed; think about old buildings with brick walls which are now used as restaurants/cafes) is run from the unit to achieve the in/out separation in both directions. Your case is different since you have to contend with isolation and space limitations (in addition to having no opening windows; think about a walk-in closet conversion to a workspace).

As I recall, you don't have a ceiling space available for this, otherwise a ducted mini split, and adding an inline ERV would provide the simplest solution, save for the one offered by Starlight.

All the best,

Paul

[Jag94]

Hey Paul,

I meant it would happen in any room that was installing this same unit. My point is, this unit is designed for smaller rooms. It can circulate that air even though the inlet and exhaust vents are on the same unit just 20 inches away from each other. So while it's not as efficient as having the intake and exhaust vents on opposite sides of the room, it will still exchange the air.

I don't have much ceiling space available, but I do have quite a bit of space on the north gable wall (where the garage door is), but my issue is not being able to service the ERV if I need to. I have thought about building some sort of access door, but I'm worried about sacrificing isolation by creating another hole in the wall.

Starlight,

The size of the unit you provided isn't the problem. I have looked at a ton of HRV/ERVs, and the problem I'm having is figuring out a way to install them in the room. That's really my biggest holdup. It's also why I'm so stuck on this particular model, is that it has a small footprint (doesn't take up a lot space inside the room), it can exchange the air at the rates I need it to (based on the specs), and i can easily service it because it's face mounted on the wall.

[Starlight]

What about mounting the unit right up high, just below the roof, somewhere above the blue dotted line at the top of this photo?

[Jag94]

Do you mean the unit you recommended?

Also, everything you see here i still the exterior frame. I haven't built the interior frame yet. The blue dotted line is the bottom of the last rafter tie/large gusset. The interior frame needs to sit just in front of this, leaving quite a large gap between the interior leaf, and the exterior leaf. There is definitely enough room in that space to put an ERV/HRV, the silencer boxes, and ducting, but I wouldn't ever be able to access the ERV/HRV to service it.

[Starlight]

Source of the postDo you mean the unit you recommended?

It doesn't have to be exactly that one but something like that, one which is a standard ventilator requiring (ie. made to use) 4 ducts.

Source of the postThere is definitely enough room in that space to put an ERV/HRV, the silencer boxes, and ducting, but I wouldn't ever be able to access the ERV/HRV to service it.

Imagine a floor with a sunken bath, like this:

There is not simply a hole in the floor but a tiled, recessed area that becomes the bath. Now turn that principle upside down: the floor is now the ceiling of your inner room and the sunken bath is now an open area in the ceiling but not actually open as in air can escape but a recessed, enclosed area, where you can mount your ventilator, something vaguely like this:

You would not be able to see the outer roof's rafters as that space would be boxed off with drywall, part of the inner room. It sounds, from what you are saying, that there is space up there for a ventilator but in your plans the ceiling would block off the space. My thinking is that without breaking the airtight seal of the inner room, the space can be utilised.

Do you get it, now? Did I explain it well enough?

[Jag94]

Yeah, I see what you're saying. Would you then put some sort of door over the open "bath tub" space, or just leave it open with the unit exposed? If you put a door, would that create any kind of reverb chamber, or 3rd leaf?

Ducting through the ceiling will be difficult because of the large gussets, so I think putting it in between the inner and outer leaf of the north wall would be much easier.

Let me stew on this a bit. I like the idea of having a "sunken" wall that houses the unit... but i imagine isolating that recess will be tough since it will have 4 ducts penetrating the wall.

[Starlight]

Source of the postWould you then put some sort of door over the open "bath tub" space, or just leave it open with the unit exposed? If you put a door, would that create any kind of reverb chamber, or 3rd leaf?

You will have two ducts coming down into the room. A door would be a challenge. So long as it is not sealed airtight it would not be a 3rd leaf, and even if it was selaed, I am not sure it would be but it would be best to check. As you are drumming and were accepting of having the ventilator in the room, maybe it will not be noticeably loud. For the 10% of the time you are tracking you could turn the speed right down to keep it whisper quiet.

Source of the post... so I think putting it in between the inner and outer leaf of the north wall would be much easier.

You will need access to clean the filters periodically so you cannot have it behind a sealed wall where access is not possible.

[Jag94]

Source of the post You will have two ducts coming down into the room. A door would be a challenge. So long as it is not sealed airtight it would not be a 3rd leaf, and even if it was sealed, I am not sure it would be but it would be best to check. As you are drumming and were accepting of having the ventilator in the room, maybe it will not be noticeably loud. For the 10% of the time you are tracking you could turn the speed right down to keep it whisper quiet.

Yeah that makes sense.

You will need access to clean the filters periodically so you cannot have it behind a sealed wall where access is not possible.

I meant putting it in that north wall the same way you suggested I do in the ceiling. Have a recessed "cubby" that allows me to have access to it.

[Jag94]

Ok so some build updates, design concepts, and some questions.

I stuffed the bays of the garage door with EPS foam so that when I stand the wall up, the OSB on the "inside-out" wall will touch directly against the door/foam. There will be no gaps, and it will be one continuous, sealed mass leaf. I attached the OSB to the frame, and with the help of some friends, we stood it up, and I secured it in place. Next up will be adding mass to the stud bays, then caulking the shit out of the perimeter and the drywall in the bays.

Thinking a LOT more about the ERV situation, I started putting down on paper (or in this case, sketchup) how this would work/look. I'm not crazy about it because it's going to take up significant space in the room, but I am concerned with making sure I'm getting adequate fresh air in the room when I have 3+ people in there playing music, sweating, breathing hard, etc... as anyone should be. So here's what I'm thinking.

There are two ERV units that meet my needed specs. This one and This one.

The first one is pretty small in dimensions and is much more affordable. It's marketed as an AEV (Air Exchange Ventilator), and by the descriptions, it seems to function much like an ERV or HRV, but for some reason doesn't have the same name. The second one is really slim (albeit longer and wider), so it would sit very high up on the ceiling, effectively not taking up much space at all. It is double the price, but it seems to be a good option. I understand Fantech is a good brand, so I probably can't go wrong with either one.

I will put the unit up towards the ceiling as high as I can on the north wall (which is where the garage door is, and where that new wall was built and stood up). The mini split will be on the west wall, and i'll have the fresh air duct feed the air right into the path of the mini split so it gets cooled/heated immediately. The exhaust duct will run along the perimeter of the room so that it's opening is on the opposite side of the room from the fresh air inlet. I imagine this will help make sure the air in the whole room is being adequately exchanged. I can build the silencer boxes so the supply and return ducts from the unit go directly into them, and then they penetrate the wall and take the air outside. This is how I imagine in. Please excuse the crude drawing of it. It's not exactly to scale, but you get the idea.

I am thinking about possibly building the silencer boxes inside the wall, instead of inside the room. This would help maintain real estate in the room. What are your guys' thoughts?

I also don't know how I'll run the ducting inside the room. I don't want it to look like shit, so I'm hoping maybe I can make it look "industrial", while not completely killing the acoustics in the room. I don't have space above the ceiling to run the ducts, so they have to be run inside the room. any thoughts/ideas/examples of how running a duct in the room could look/work?

I am about to build the interior frame, and as soon as I do, electrical and HVAC will need to be figured out so I can make sure I plan everything accordingly for when it's time to put up the OSB and drywall. I am planning on running a star grounding system with isolated ground receptacles. I have done a TON of research on how to do this, but I wanted to put it down on paper to run it by everyone to see if it makes sense, and is correct.

Right now I have a 200 amp main panel for the house. There is a ground rod right at the main panel, and another one at the front of the house bonded to the water pipes. Currently there is a 40amp sub panel in the garage, that is fed by 10ga wires in conduit underground. There are 2 hots, 1 neutral, and 1 ground wire. I want to turn this into a 60 amp sub panel, so I'm going to swap the 10ga wires with 6ga wires, and put a 60 amp breaker in the main panel. The only electrical penetration through my interior leaf will be the main power. I will be face mounting all outlets, switches, lights, etc to the drywall, all connected by conduit. As far as the star grounding system goes, I understand that each one of my IG receptacles needs to have a hot, neutral, and insulated ground. Each insulated ground will make a home run to a separate ground bus bar, that will then run all the way back to the main panels ground bus, but never touching the equipment ground bus (or ground conductors) in the sub panel. All the outlet boxes will be metal, and will be connected with EMT conduit, so that will act as the equipment ground for each IG receptacle. So this means I will need to run a 5th conductor (the isolated ground wire) through the conduit back to the main panel. These isolated ground receptacles (I'm thinking about 7 total) will be for audio gear only. I will have regular outlets and circuits for other things like lights, AC, refrigerator, etc.

Do I have this right? A diagram would probably be easier to understand. But with everything I've read and seen, this seems to be the correct way to do this. Anything I'm forgetting or should be aware of?

[Starlight]

Jag94, those look like two capable ventilators. Well done on finding them.

Source of the postI am thinking about possibly building the silencer boxes inside the wall, instead of inside the room.

A silencer is basically an empty box. If you put that in a wall then the wall will not have mass at that place and it will be an isolation weak spot, a place where sound leaks in or out - as a drummer, perhaps more the latter. In principle it does not sound like the right plan.

Source of the postany thoughts/ideas/examples of how running a duct in the room could look/work?

The 8" ducts went up in my room only last week, here. I am guessing you will use 4" or 6". Mine looks sort of industrial at the moment with the duct wrap. Is that the look you are wanting? Don't forget that your duct will be partially hidden by the depth of the acoustic treatment you have on the ceiling. In fact, if you have corner trapping, which is always a good idea as bass builds up in corners, you can hide most of the duct, like in the photo showing what I did in a previous place. In my current studio, the designer wants me to put up a drop ceiling (but with home-made acoustically transparent tiles) so mine will look more like an office than industrial.

[SoWhat]

Greetings jag94,

From your illustration of the silencers, one thought has occurred to me: in the "vertical" orientation you're showing, you might want to add another stud (and possibly beef them up) to support the boxes. Gravity will be working against you, and the weight distribution is something to consider.

All the best,

Paul