I have trolled these forums for a while now and gathered different ideas for my theater design while I waited for permits etc to go through on my new house.

Eventually I settled on a design that maximizes my use of the space allowing for my MAME machine without putting it in the actual theater sitting area.

After roughing in my cat-6 for the home network today I took a better look at the HVAC layout and started to get concerned.

The theater room is basically a bonus room above my garage. The dimensions of the room are 20' x 22'.

I will split the room into two sections, one to act as a lobby for an arcade game and my AV + Home Networking equipment (~4' x 22'), and the rest to act as the theater area (16' x 22').

The HVAC layout is very strange in this room, with what appear to be two 8" vents that will end up in the lobby area, and 0 returns for the room.

Since all equipment apart from the projector, speakers, and screen will be in the lobby area I imagine the cooling requirements there will be greater.

The theater area seats 8 but most often will have 2-4 people outside of party occasions.

I am not sure if I should have one of the air supplies from the lobby moved to the sitting area, and replaced with an air return, as well as an additional return in the sitting area giving one supply + return in the lobby and one supply + return in the theater or if the theater area itself would require 2 supplies + 2 returns, giving the room total 3 supplies + 3 returns.

If the AV equipment is not housed in the theater portion should one 8" supply + return be sufficient?

The lobby area will be connected to the theater sitting area via a 4.5' wide x 7' tall opening so there is air flow between the lobby with its one duct and return and the theater portion.

The house is still under construction, and although the Mechanical Inspection has already been completed there is a slim chance I can get some modifications made, after the insulation and drywall in two weeks I am out of runway. (These guys are not all that response to my concerns regarding use of the room as a HT because I did not hire their A/V installer, due in part to budget, and in part to his lack of credentials. )

Thanks for any advice,
Stephen Goldberg

I am at the HVAC stage in my new theater. All my equipment will be in the theater along with seating for 8 people. The theater is 18' X 21' with an 11' X 18' office next to the theater. I have installed a 1½ ton heat pump to take care of this addition. In the theater I will be installing 6 supplies and one return. In the office area I will have 2 supplies with no returns. The thinking on not having a return in the office is that I didn’t want to open up a direct path for sound to find its way into the office. When the theater is not in use the door will remain open. My HVAC guy seems to think this will be OK.

In my current theater that is in half of a two-car garage I only have one supply and no returns and I can’t cool that area down. So I am taking no chances in the new theater.

Wow 6 returns.

That is some serious air supply.

No way the spec builder would be willing to add so many for me.

Stephen Goldberg

No, 6 supplies. Three on the right side of the theater and three on the left with the return center back.

http://i61.photobucket.com/albums/h61/willygib/IMG_0695.jpg

Damn thats some sexy ducting too. Mine look like slinkies wrapped in aluminum foil.

I think I am better off doing it seperate from my builder after the construction.

Stephen Goldberg

The typical home theater will require in the area of 9000 to 11000 BTU's per hour of cooling. (In a bonus room above a garage the number will be significantly higher...not only due to the higher heat gain through the roof; but, it is likely the only space in your home with non-environmental rooms on five of its six sides.) This will NOT happen without both supplies and returns in the room. Further more, the HVAC system should be NC17 (if your HVAC contractor doesn't know what that means, fire 'em). You do not want more than 250 FPM velocity through any of the supplies or the returns. A hot and stuff theater will not be used regardless of how much you spend on the gear.

If your HVAC contractor "seems to think", that means he doesn't know. If he doesn't know, insist that he find out.

Dennis,

Is a noise criteria of 17 that hard to obtain in a home theater with multiple supplies and a single return?

Thanks for the reply Dennis. I read your earlier threads so was aware of the 9000 - 11000 of the average theater, however the threads seemed to indicate the larger chunk of that was due to the equipment being in the same room.

I was hoping that without the equipment in there I would be alright, but deep down I guess I knew it wasn't going to work.

I spent so much time learning about acoustics, sound proofing, electrical, etc I paid little attention to HVAC requirements and now it has bit me.

Being a spec house it is difficult to get anything modified from their spec, even more so at the current stage of construction.

Thanks again everyone. I will get through this construction phase for the rest of the house, and eventually find a way to retrofit some HVAC modifications in.

I think I will pursue a seperate upstairs and downstairs unit, with a multizone system upstairs so I can have seperate control in the theater as I believe was suggested in another thread.

Amazing how much knowledge is shared on these forums.

Stephen Goldberg

NC17 will not be achieved without (a) an experienced HVAC contractor; and, (b) prior planning. Most residential HVAC contractors don't have the experience to do this...and there is no need for it to be a costly process. As to your direct question...noting the size of the supply register fittings, it ain't going to happen in your case. I don't know what the size of the return is, how many 90 degree turns between the return and the air handler, nor if the return trunk is lined, isolated, or otherwise.
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Sitting in your chair, sleeping, is 500 BTU's per hour; but, you are correct, equipment is a big source of heat (which still needs to be cooled) and noise. The bonus room concept, however, is a bondogle that is very seldom adequately heated/cooled because the Low Bidder for your HVAC system doesn't care, cannot afford to care, and isn't going to live there in the first place. Your first clue that you're going to have wild temperature variations in your multi-story home (and costly monthly heating/cooling costs), is the builder's "cheap out" approach of using a single HVAC unit for both floors (and non-zoned at that).

Let me give you a common example of the bonus room nonsense. I can go into any number of homes in the Atlanta (or other areas) and find a main floor room that is over a heated basement, under a heated bedroom, and with only one exterior wall. I can see the size of the supply (and return if installed). Then I can find the bonus room. Only ONE of the four walls is adjacent to a heated space, the floor is over a non-heated garage, the ceiling is either exposed to a non-heated attic (or the roof itself), YET I'll find exactly the same size of the supply (and return if installed). If anyone thinks that room is adequately conditioned, they likely have bought a couple of bridges (likely the same bridge several times).