Humidity controlling air conditioner and fresh air

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I need to figure out an HVAC solution for a small studio I'm building in the middle of a warehouse (on the 3rd of 6 stories). See the following drawing for the current design (note 12' ceilings): https://www.dropbox.com/s/pzv282ewgkly4 ... A.pdf?dl=0 I have a friend who will install, but our budget for HVAC materials is currently very low ($2000...I know :| ). We might have more to spend in 6-12 months, so perhaps there's a way to do this in phases? Any suggestions? EDIT: I've read the FAQ's, the forum rules, and 'Build It Like The Pros' book. I generally know about my options, but most of them are outside our current budget. So I'm hoping some of you can help me think of something clever. :wink:

I need to figure out an HVAC solution for a small studio I'm building in the middle of a warehouse (on the 3rd of 6 stories)

For a project that big, you should probably start your own thread, rather than tag onto the end of this one.

See the following drawing for the current design (note 12' ceilings):

I'm not sure I understand your nomenclature: When you say "Edit Room", are you referring to the control room, or to something else? When you say "Recording booth", are you talking about something like an isolation booth, or vocal booth, or did you have something else in mind? And when you talk about "Main Studio", are you referring to the tracking room / live room, or is it something else? Assuming your "edit room" is actually the control room, then having it both 12' long and 12' high is a bad idea. Do some research on room ratios, modal spread, Bonello charts, and suchlike. You should fix that before you think about adding any HVAC.

I have a friend who will install, but our budget for HVAC materials is currently very low ($2000...I know

Ummmm.... it's not only low, it is totally unrealistic. You have three rooms in there, totaling 700 square feet of floor area, and well over 8000 cubic feet of volume. You will need either three different mini-split systems, probably with capacities of something like 9,000 BTU/hr, 12,000 BTU/Hr and 36,000 BTU/Hr, and that's without even considering the ventilation! Each of those will cost a couple of grand, and antoher several hundred for installation.... Your only other option would be a single AHU with multi-zone capability, or with a multi-zone system controller and electrically operated VAVs... but that would likely increase your cost even more.

We might have more to spend in 6-12 months, so perhaps there's a way to do this in phases?

Assuming that you don't need to use the other two rooms at present, you could start with just one of them now, but even then I doubt that 2k is going to cover it. For example, if all you need to do is to mix stuff that has been tracked elsewhere, then just put a single mini-split in the control room, and build the set of four silencer boxes that you will need for that, then add the ducts and fan. But that's going to be over 2k, I would expect.

I generally know about my options, but most of them are outside our current budget.

Then take the hint! If all of the options that you can find are beyond your budget, then it's pretty obvious that the problem is your budget! :) Multiply by five, and you are probably in the ball-park. But before you buy anything, you first need to do the math. You need to know how much air you will need to move in each room (flow volume and flow rate), and how fast you can move it (flow velocity), in order to figure out the sizes of your ducts. Based on that, you can figure out the sizes of your silencer boxes. Based on that, you can figure out the static pressure. Based on that you can figure out what fan you need to move the correct amount of air at the correct speed when facing that static pressure. Then you also need to figure out the latent heat load and the sensible heat load for each room under all circumstances, from zero occupancy to full occupancy, from no gear turned on through to all gear turned up to 11, and for the coldest day in mid-winter though to the hottest day in mid summer. Based on all of that, you can correctly dimension the actual mini-split for each room (or the central AHU, if you go that route). You cannot decide on the equipment, ducts, silencers or fans until you have all of that worked out in detail. If you did then you'd be guessing, and guessing is never a good way to design a studio. - Stuart -

Yea, I figured that was the case. Ok, I'll go back to the drawing board and start a new thread after we settle on a new direction. Thanks for the reply Soundman2020!

Soundman2020 wrote:

For single-room studios I usually use a mini-split plus a duct system for the fresh air inlet/stale air exhaust (with the Ururu unit in a small room you only need exhaust), but for larger facilities with three or more rooms I tend to go with a central AHU plus plenums, ducting, variable dampers and a system controller. The two-room studio can go either way. But regardless of whether you decide to go split or AHU, you still need the ducting and silencer boxes. You can't avoid that. - Stuart -

Hi Stuart. Is the Ururu Sarara split system still an option you'd recommend for single room studios? It seems to have some good features and sounds like it can provide a good amount of fresh air. Daikin says it can fill a 26m2 room in 2 hours. If we assume a ceiling height of just 2.4m, that equates to almost 9 litres of fresh air per second. On the downside, the indoor unit which can run at between 42db to just 19db depending on fan speed, still might not be as quiet as a well designed ventilation system with appropriately balanced airflow rates, duct sizes and silencer boxes. Is this a fair assumption? Thanks Stuart.

says it can fill a 26m2 room in 2 hours.

ASHRAE recommendations call for 5 to 10 room air changes PER HOUR! In other words, all of the air in a room should be replaced every six to twelve minutes, not every two hours... A good rule of thumb for a studio is 6 changes per hour, or one every ten minutes. So in a 26m2 room that is 2.5m high, the volume is 65 m3, so the flow rate for 6 changes per hour would be 65 x 6 = 390 cubic meters per hour, or about 7 cubic meters per minute. In imperial units, that's roughly 230 CFM. Here's some interesting reading on the subject: http://www.contractingbusiness.com/serv ... e-room-cfm http://www.engineeringtoolbox.com/air-c ... d_867.html http://www.engineeringtoolbox.com/venti ... d_115.html http://isites.harvard.edu/fs/docs/icb.t ... 1_2004.pdf The unit itself is probably fine, and should work well as an air conditioner, but the fresh air supply does not meet building code requirements, from what I can see. It's probably fine for supplementing the flow in a typical bedroom, office, shop, etc., but those are not sealed airtight, like studios must be. There's plenty of natural air infiltration in ordinary construction that does not happen in studios.

On the downside, the indoor unit which can run at between 42db to just 19db depending on fan speed, still might not be as quiet as a well designed ventilation system with appropriately balanced airflow rates, duct sizes and silencer boxes. Is this a fair assumption?

:thu: - Stuart -

Hi Stuart. Oh dear. It seems I'm having another ventilation brain spasm. Ouch. I'm just ... not ... getting ... this. You mentioned that all the air in the room should be replaced every 6-12 minutes, but in this other thread (http://johnlsayers.com/phpBB2/viewtopic ... 86#p141934) it sounds like you are saying that the air does not need to be replaced, just recirculated, while adding in a fresh air component. Do the words 'replaced' and 'recirculated' have the same meaning in this context? The Urura Sarara has an airflow rate of roughly 200 litres per second (presumably that's recirculated air from within the room), but can also bring in 9 litres per second of fresh air. Does that not tick all the boxes for air circulation and the fresh air component? EDIT: I've re-read some of your other posts about ventilation and some other online articles and I think I've answered my own question. I think I'm just getting caught up on the word "replaced" which I wrongly interpret as meaning "all the air in the room needs to be replaced with fresh air". My understanding now - and correct me if I'm wrong - is that all the air in the room does need to be replaced multiple times per hour, but this is achieved primarily through re-circulation. Some fresh air does need to be added in to that mixture though, and an equal portion of air evacuated completely. I also concluded that the Ururu Sarara (now called the US7) might be effective for a control room with a limited number of sedentary occupants, but would fall short in a room filled with sweaty musicians bashing it out. Here endeth the brain spasm.

Hi Stuart I'm trying to ascertain the fresh air volume for our studio. I have found out that an average human breathes in about 1/2 cubic metre of air an hour. If I use the example of say 10 adults in the studio(that would be fun) as a maximum that would roughly work out to be 5 cubic metres of fresh air required every hour. Does this sound right? We are setting up a ducted system in our live room and control room. One unit feeding both rooms with dampers, silencer boxes etc. I hear that the HAVC contractors just add a small duct from the outside then attach to the main unit in the ceiling to bring fresh air into the circuit. Do I let them know that that we need a minimum of 5 cubic metres of fresh air for our system?

There's two concepts here, Anthony, that often get confused and muddle together. One is the total flow rate of the system: how muc hair you need to move through the room every hour, to ensure even mixing, good temperature distribution, proper humidity control, good control of stale air, etc. The other is how much FRESH air you need to add to that, to keep people alive, and even more important, how much STALE air you need to remove in order to keep people alive. On that second point: Many people assume that the reason for bringing in fresh air is to provide enough oxygen: that's partly true, but it's not the real reason. The REAL reason is that you need to get rid of the CO2! You exhale a large volume of CO2 with every breath, and it builds up fast in a sealed room. Since the concentration of CO2 in air is very small (about 0.04%), you don't need to add a lot before the concentration gets up high. On the other hand, the concentration of oxygen is about 21%, so even if you use up a LOT of oxygen as you breath, there's still plenty there. You will die from CO2 poisoning long before you die from oxygen starvation, and CO2 rises very fast in sealed spaces, much faster than oxygen decreases. And you pass out from CO2 poisoning long before you pass out from lack of oxygen. And way before that, at much lower Co2 concentrations, you start to feel bad, suffer headaches, nausea, vision problems, attention problems, ... way before your body even notices the slightly lower level of oxygen. You can die in a room that has plenty of oxygen available, if the CO2 is high enough. You can live with only 15% oxygen in the room (6% points down from normal), but 6.04% CO2 (6% points up from normal) is not something you want to have in your room, if you plan to live.... :shock: .... So firstly, you need to REMOVE enough CO2 (stale air) to keep people alive, and in order to do that, you need to provide enough fresh air to replace the stale air that you removed. And that's the reason why you also want to move a much larger volume of air around the room, and through the room: to ensure that the fresh air comes on and mixes with the room air, so that the concentration of both CO2 and oxygen stays about the same THROUGHOUT the room. Consider this: If you sit still in one place and there is no air movement at all in the room, then you create a "bubble" of atmosphere around you that is high in CO2, low in oxygen, high in humidity, high in temperature, etc... while over in the corner of the room, it is cooler, dryer, and with a property balanced mix of CO2 and O2. So, firstly you need to ensure that you are bringing in enough air and removing enough stale air to keep everyone alive and comfortable. That's what you are talking about. Also sometimes called "make-up" air in HVAC terminology. Yes, you need ducts in your HVAC system to do this. First, a duct that dumps some of the room air overboard, into the outside world, and ANOTHER duct that brings in the same amount of fresh air from the outside world. That's the first part. That is based on occupancy: how many people there will be inside the room. Then thees the SECOND part, which is just recirculating air through the room to ensure good mixing, so that temperature, humidity, CO2, and O2 are pretty much contant throughout the room, with no "pockets" of hot, humid, "bad" air, nor of cold, dry, "good" air. The general rule here is that you need to replace the entire volume of air in the room, every ten minutes or so. In other words "6 room changes per hour". Some people recommend more than that, such as 8 room changes per hour (roughly one every 8 minutes), or even ten per hour (once every six minutes). But for a typical studio, 6 per hour is about right. And certainly no less than that (for example, 4 per hour would not be enough). Therefore, you need to calculate the TOTAL air volume in ALL of your rooms, multiply that by 6, and that's how much air your AHU must be able to move, under normal circumstances, on average. That's NOT the maximum amount when it is running full bore! It's the normal amount when running normally. You also need some "headroom" in the system, for dealing with difficult days.... So when you dimension your HVAC system, your AHU must be able to move enough air to replace the entire volume in all of your rooms, 6 times per hour. That is your flow rate. Then IN ADDITION to that, you need to have your "make-up" air ducts, that bring in a much smaller volume of fresh air, mix it with the recirculating air, and also take some of the recirculating air and dump it overboard. That might or might not need an additional fan to drive the make-up air, and you might or might not decide to add an HRV to the make-up air system, to recover some of the energy that would otherwise be lost from dumping the stale air. Then, when you have figured out all of that, only now can you start dimensioning the ducts that fo to your rooms, and the size of your silencer boxes and registers. Because only at this point, after you have done all the above math, only now do you know how much air is flowing through it! You cannot decide on duct sizes or silencer boxes BEFORE this point, because there's nothing to base it on! So, you know how much your air flow rate is (cubic meters per hour) through the AHU, ducting and silencers: and you also know the maxim air flow velocity (about 1.5 meters per second), so now you can do the math to figure out what the duct size must be to get THAT speed at THAT flow rate. The speed cannot be higher, or it will create noise just due to the movement of air. So that's your limiting factor here. The speed can be lower if you want, and that's great. So, with that info in hand you can now calculate what size ducts you need, and what size registers you need, and therefore what the interior dimensions of your silencer boxes need to be, since the air flow speed must suddenly drop by at least half at the entrance, and double at the exit (at least). So now, with all THAT in hand, you can finally calculate the last piece of the puzzle: what your static pressure will be, for the duct, silencer, and register system that you have designed. Then you need to check that calculated static pressure against the specs of the AHU units you are considering, and find one that can handle that much static pressure. If none of the ones you are considering are able to handle that pressure, then either you need to look for a larger AHU and run it on a lower setting, or you need to modify your duct/silencer/register system to decrease the static pressure such that it is within the range of the AHU. You CANNOT run an AHU into a system where the static pressure is too high: that will cause the fan blades to stall, or at least work outside of their design range, thus causing the fan motor to work much harder than it needs to, but it still won't be able to move the correct volume of air at the correct speed, the fan will overheat, the life span will be shortened, the fan will fail, and apart from that, even while the fan is working, the rooms will not be cooled or dehumidified properly, and you won't be supplying enough air, either in re-circulation of in make-up. So there's a lot to take into account here. Normally when I design a studio, I spend as much time on the HVAC system as I do on all of the rest! It's a big deal, and getting it wrong is an even bigger deal...

We are setting up a ducted system in our live room and control room. One unit feeding both rooms with dampers, silencer boxes etc.

Fine, but are you going to adjust those manually, or are you going to have a system controller with sensors to do that for you automatically? If you opt for a manual system, you will have to be adjusting the dampers, flow rates, flow speeds, and temperatures constantly, yourself.

I hear that the HAVC contractors just add a small duct from the outside then attach to the main unit in the ceiling to bring fresh air into the circuit.

Right, and the also add a similar sized duct (generally a bit larger) to exhaust the stale air from the system. And BOTH of those ducts must be sized correctly to provide the correct flow rates without increasing the static pressure too much.

Do I let them know that that we need a minimum of 5 cubic metres of fresh air for our system?

No. Either you find an HVAC contractor who already understands studios and has done several, successfully, and provides references for you to go check, or you find someone to design the system correctly for you, and hand over that design to the contractors, with the instruction: "build it like that". If your contractors have no experience in doing HVAC systems for studios, then they won't understand the need for low velocity, high volume, low noise, silencer boxes, insertion loss, etc. They'll do it like a normal house, office, shopping center, church, school, etc, and it will be too noisy to be useful, and won't control the humidity and temperature correctly. There's a lot of reasons why that is, but too many to go into. HVAC is a much, much bigger issue than most studio builders realize, and much more different for studios than most contractors realize... unless they have done it before, successfully. First rule of thumb: don't let an inexperienced contractor with no studio experience design your system! - Stuart -

Thanks for the great explanation. It makes so much sense now. I'm sure this will help a lot of people. Good question about the control dampers, I will have to ask our contractor. Do you design studio HAVC systems for clients so they can hand to their contractors?

Thanks for the great explanation. It makes so much sense now. I'm sure this will help a lot of people.

:thu: I'll PM you about the rest. - Stuart -

Hi Stuart Using the great information you gave us below I was able to calculate the duct diameter we need for our studio. Our Control Room has a volume of 72 cubic meters and the live room is 36 cubic meters. So.... 6 room changes per hour (6 x 108 m3 = 648 m3/per hour) divided by 60 = 10.8 m3/min - Control room 2 x supply air ducts 250mm diameter - Control room 2 x return air ducts 250mm diameter - Live room 1 x supply air duct 250mm diameter - Live room 1 x return air duct 250mm diameter We calculated that for 6 air changes per hour for both rooms we need 10.8 m3/min Based on a Max air velocity of 1.5 meters/sec as suggested we calculated the following... A 250mm diameter duct @ 1.5 meters/sec = 4.4 m3/min air volume. So - 3 x 250mm supply ducts(two for control room and one for the live room) will push through 13.2 m3/min @ 1.5 meters/sec air flow velocity as a maximum. Our total NORMAL studio requirement (CR & LR) is 10.8 m3/min So this means we have about 22% more flow capacity to reach our Max air velocity of 1.5 meters/sec as suggested. What do you think? If this is correct................then the silencer boxes would be as follows. Lets say that the 250mm diameter duct calculated to make a square is 220mm x 220mm. If I say at least make it twice the cross sectional area that would mean that the internal size of the silencer box would be 380mm x 380mm! That is quite large for an internal cross sectional area but if it has to be then I guess it will have to be. It will make the boxes very large and I will have to make 6 of them. 3 for the supply air and three for the return air. :shock:

I hear that the HAVC contractors just add a small duct from the outside then attach to the main unit in the ceiling to bring fresh air into the circuit.

It is right that to add a duct. I wait for your fresh air into the circuit. Thanks

The Humidity controlling air conditioner and fresh air supplier are very very good thing that can use every person for his/her personal purpose.

Thanks for adding a location to your profile, "kabinsons1", but I'm surprised that there is a city called "La Jolla, California", located in south east India, close to Bangladesh!

How can control my humidity with an air conditioner?

kabinsons1 wrote:

How can control my humidity with an air conditioner?

Simple: Turn it on.

That looks great! I'm impressed. Is it very noisy? I'm not interested in something that will take away from my studio.

Hello folks, This is my first post, and I am hoping for a simple reality check from experienced folks related to ventilation and AC in my under construction home studio. For the last year, I've been building a small drum room in an existing structure in my backyard. Interior dimensions are roughly 8' x 10' with 7' ceilings. We framed a room within a room within the original framing, 2 leaf design, interior and exterior walls both have a layer of Auralex sheet-block wedged between their respective layers of sheet rock or siding, with 2 isolated doors, no windows. It is a stand-alone structure on a concrete slab. Knowing what I now know from reading here I would have done alot of things differently, but such is life, the money is spent and my needs are modest. I don't plan on doing any serious recording in the room, it is primarily a jam room for myself and possibly a few friends that I can play in during the evening without disturbing my suburban neighbors. I am currently looking to add some ventilation to the room, despite any acoustic or isolation problems the room will have, it is effectively air-tight. This thread keeps coming up every time I google for solutions which is why I am posting here. Having learned from my mistakes, I am looking to have a mini-split AC system installed by a local reputable HVAC shop. So far the most concrete recommendation I have received is for a 9000 btu Fujistsu mini-split system. I am in central California so temperature and humidity are mild, but I know it will get hot in there. The part that I am confused on is 2 different "professionals" have told me that the mini-split should be sufficient to bring in new air from the outside and remove old air. This doesn't seem to jive with everything I have read here regarding the need for additional ventilation and ducts to move air/humidity into and out of the structure. I know extremely little about the subject, so am torn on trusting these experts. Can someone here let me know if I am off base on this? Thanks for your time.

Hi there " owr ", and welcome! :) Congrats on building your place! It sounds like you have done quite a bit already. Like you say, there are things you could have done different, but that's water under the bridge now...

The part that I am confused on is 2 different "professionals" have told me that the mini-split should be sufficient to bring in new air from the outside and remove old air.

The vast majority of mini-split systems do not include ventilation. A very few of them do have a small fresh air intake pipe, but even then it isn't sufficient for studio needs. Most mini-split systems simply recirculate air inside the room, and either heat it, cool it, dehumidify it, or do nothing to it except move it. Those are the typical non-ducted units that you see on the walls of rooms. But I'm wondering if the professionals that you spoke to were talking about DUCTED mini-split systems, that are meant to be part of a complete system. Non-ducted ones just hang on a wall, suck in room air at the top, then blow it back out the front. Ducted systems (also called "AHU" for Air Handler Unit) are not mounted inside the room at all: they are external to the room, and mounted inside a duct. OR rather, there's one duct leading into the unit, which is the "return" duct coming back from the room(s), and one duct leaving the unit, which is the "supply" duct that takes the conditioned air to the room(s). The "return" duct usually has another duct branching off from it, to dump stale air overboard, and an additional duct feeding into it, which is fresh air from outside. In that case, the "mini-split" really is supplying fresh air to the room, and removing stale air, but not by itself! There's the entire ducting system associate with it, and there is usually also some type of fan that is either forcing the fresh air into the return duct, right before it goes into the AHU, or sucking stale air out of that duct, further upstream. So ask those guys if they were talking about ducted mini-splits, or not. Here's what the two different types look like: The one on the left is the typical non-ducted "wall" unit type of mini-split condenser, and the one on the right is the ducted "AHU" type of mini-split condenser. Here's a typical AHU mounted in the ceiling space, above a room, showing the ducts: As you can see, there are small plenums on either side of the actual AHU. The ducts connect to the plenums.

So far the most concrete recommendation I have received is for a 9000 btu Fujistsu mini-split system.

That sounds about right, but do take into account that you need more capacity in a studio than you do in a typical house, for several reasons: 1) occupancy: you will have more people in your room than you would in the same sized room in a normal house, 2) biology: they people that are there will be "working" in the sense that they are not just sitting still, doing nothing - they are playing instruments, jamming! 3) gear: the musicians will be using instruments that produce heat: amplifiers, computers, foot-pedals, effects boxes, etc. So the sensible heat load is higher than normal, and the latent heat load is higher than normal. While 9000 BTU might be fine for a typical room of that size in your house, you probably need more in your case, because it is a studio. There's also the issue of how much fresh air you will be bringing in: that has to be treated by the system before getting into the room. If the incoming air is very humid, or very hot, then you need a larger capacity in BTU to deal with that. There's a lot more to HVAC than meets the eye at first glance.

This doesn't seem to jive with everything I have read here regarding the need for additional ventilation and ducts to move air/humidity into and out of the structure.

Right. Although the ducts are not really there to move humidity in and out: They sort of do that, yes, but only because the air that they are designed to move has humidity in it. The AHU itself deals with the humidity: it removes the humidity form the air by condensing it out as liquid water, which needs to be drained away somewhere. That's referred to as the "latent heat load" of the air. The interesting thing is that the AHU CANNOT cool the air until it has first removed enough humidity! So if your AHU is too small, it will use all of its BTU capacity just in removing humidity, and there will be none left over for cooling: so the room will never cool down, even though the humidity will be fine. This is why you need to make sure that you account for the latent heat load in your calculations. That latent heat loads comes from several places: 1) moist air coming in from the outside world through the fresh air intake duct, 2) every breath that each musician exhales has 100% humidity. The harder they breathe, the more humidity the put into the air, 3) Sweat: if they are jamming hard, they are sweating. That sweat evaporates from their skin into the air, which increases the humidity, 4) beverages: every cup of coffee, glass of soda, beer, water, or whatever, is also evaporating, putting more humidity unto the air. 5) food. Things like pizza, hamburgers, even salads, have wet surfaces, from which water evaporates. Etc. So if you and a half dozen buddies are jamming away intensely in there, breathing hard and sweating, while eating pizza and drinking beer, on a hot humid day, there's a very high latent heat load in the air inside your room, and the AHU has to remove that BEFORE it can start cooling the air. Therefore, it is very important to do the math, and figure out your latent heat load, as well as your sensible heat load. The sensible heat load is things like computers, lights, amps and other gear that the musicians might be using. Aything that uses electricity will be putting out plain old heat, which is referred to as the "sensible heat load" in HVAC jargon. So: you need to figure your total heat load, which is the sum of latent and sensible, for the very worst case: hot humid day, room full of hot sweat musicians playing hard, eating and drinking, with stacks of powerful gear running full-bore. You dimension your mini-split to be able to handle that load when it is running on its highest setting. It can then run on lower settings under less extreme circumstances.

I know extremely little about the subject, so am torn on trusting these experts.

Find out if they have extensive experience in designing HVAC for recording studios, or if they are just typical, ordinary HVAC guys that deal with houses and offices. Studios are VERY different from houses and offices. If they have little or no experience in doing HVAC for recording studios, then you are probably talking to the wrong people. Designing HVAC for a studio is a big deal: When I design studios for my customers, I often spend as much time on getting the HVAC right, as I do on the entire rest of the studio! I'm not sure if you have seen the corner control room thread ( viewtopic.php?f=2&t=21368 ), but that's a typical example. There's not much in that thread about the HVAC, as the thread is all related to the final acoustics treatment of his control room, but you can see some of the HVAC in a few of the photos. But basically when I designed the corner control room studio, I spent a LOT of time on getting the HVAC right (pages of calculations!), and the owner spent a LOT of time building and installing the various parts of that system. The reason you can't see much of it in the photos in his thread, is precisely because I took a lot of care to hide it! The registers are flush with the visible ceiling surface, and most of the ducting is inside the ceiling cavity, above the inner-leaf ceiling of the actual rooms, but below the middle-leaf isolation ceiling. In the corner control room case, there is an AHU (ducted mini-split) that is completely outside of the isolated area of the studio, in the ceiling space above the bathroom. It connects to the studio through a pair of silencer boxes above the hallway, outside the bathroom. And from there it is distributed to the individual rooms, also through a pair of silencers for each room. Here's an overview of the HVAC system design in the corner control room studio: Thu AHU is marked, in the lower left corner of the image. Represented as a simple metallic box. The fresh air intake is through the front wall of the building, just to the right of the AHU: it looks like a rectangle on the exterior wall. The stale air exhaust is up through the vertical duct above the bathroom, out through the roof. In that image, the ducts are color coded: all the metallic silvery color ducting is "supply" air, going into the rooms, and all the ducting colored light brownish-pink color, is "return" ducting, taking air out of the rooms and back to the AHU, or exhaust. OK, that's more complex than what you need in your case, because that's a professional purpose-built studio with control room, live room, bathroom and lobby, but it gives you an idea of what is involved. Hope that helps get you on the right track! - Stuart -

Stuart, Thank you for the welcome and detailed response, it is more than I hoped for. I haven’t done my diligence yet on calculations and need to put some time in. The hvac guys I’m working with are primarily residential/commercial folks, but claim to have worked on studios before. I just had their estimator our this morning and am pretty sure he was recommending a simple ductless system, which is what has me concerned. Im going to wait until he talks to his engineers to get an official recommendation though before I pass judgement. I’ll report back with results. Thanks again for the response and running such an informative forum. Best, Oren

Soundman2020 wrote:

Guit-picker wrote:

Now that five years has gone by since this post started... and now the link doesn't go there any more, is there a "favorite" multi-split system that has risen as a "shining star", so to speak? I can't find a model number of the original post. I know it is made by Daikin.

2 minutes on google: http://www.daikin.com.my/products/urusara7/ http://coolworldaircon.com.sg/daikin-aircon-urusara-7/ http://www.daikin.co.id/products/reside ... index.html :) That looks like the one John was talking about. - Stuart -

Thanks for the link.

Man oh man the amount of spam that this forum gets hit with is full on. Moderators - I feel for you. If you’re getting tired of manually deleting all this crap then perhaps it’s time to update the forum with some better spam blockers etc. There are plugins that could help with this.

chrispire wrote:

Man oh man the amount of spam that this forum gets hit with is full on. Moderators - I feel for you. If you’re getting tired of manually deleting all this crap then perhaps it’s time to update the forum with some better spam blockers etc. There are plugins that could help with this.

Yup. It gets boring, but it only takes a few seconds to permanently ban one, and there's just one or two a day, so no big deal. In fact, I can get rid of them much faster than they can register, so it's a net waste of time for them! 8) We already have several anti-spam measures: the ones you see are just the ones that get through. Some of them are really persistent little scumbags. I have no idea why they would even think that anyone here would be interested in WiFi blockers, terrible quality shoes, very badly built condominiums, or disgusting nursing homes! It would make more sense if they were trying to hawk audio gear, US$ 5,000 speaker cables, or useless building materials, but why would anyone here want an essay-writing service? I guess they aren't the smartest dung-beetles on the planet... :) - Stuart -