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Discussion Starter · #1 ·
I hope to start construction soon on my basement theater, but I'm still struggling with the HVAC requirements. To recap, I have NO existing ductwork, air handlers, or compressors available for the basement. If I wanted to do a traditional central air system, I would have to add all that equipment at a substantial cost.


So far we've spent the winter in the home, and I think that baseboard heaters or a vented NG heater will be the way to go for heat. Simple installation, inexpensive, and quiet.


Now for the hard part...Cooling and circulation of air. In my theater, I will have a soffit that runs the entire perimeter of the room, front, back and sides. My construction friend who is helping me build this room had a suggestion. On the back soffit, we install an isolation wall inside to effectively split the soffit into two chambers. On one side we install a cold air return (or in this case, a hot air exhaust), and on the other side we install a quiet duct fan (which I can actually install external to the room). This will serve to circulate air into the HT from the rest of the basement.


I'm hoping the rest of the basement stays cool enough for this to work. So far, we've had a few 90 deg days, and the temp in the basement stays a cool 70 deg. I know we'll be adding heat with lots of bodies and heat from the subs and projector. Worst case, I can add a window unit (walkout basement) in the other part of the basement to provide a source of cool air to duct into the theater portion.


Should I extend the ducting all the way down one of the side through the side soffit to the front of the theater and install one of the ducts there, in order to draw air all the way across the theater, or will the ducts in the back be sufficient?


Any other creative ideas for adding cooling to a basement that's already pretty cool? Am I being over paranoid about the cooling requirements, or underestimating the amount of heat buildup?


Thanks for any and all opinions.
 

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I'm no expert, but having your register (inbound air) and your return (outbound air) in close proximity will do you no good...air won't be able to circulate. Some people advocate registers low in the front and return(s) high in the back; some advocate registers high in the front and return(s) high/low in the back. I ended up adding a new zone for the HT and the equipment room--two registers hidden in the right/left soffits near the front and one return in the ceiling at the rear, centered. The goal is to get cold air *circulating* in the room (in my room, air will move front to back), and I think your first plan as outlined won't do that--but adding ductwork to take the inbound air up front, so that the "return" (I guess you can't call it that if it's not part of an "official" AC system! :)) in back could suck it out, seems like it would work better.


Also, NEVER underestimate the heat generated by a projector--especially a CRT projector. My last HT hit 85*+ after about 30 minutes in the sweet spot, with the A/C on full blast into the room. This time, I've installed a venting system up behind the projector to try and nullify the heat output--just a long, 6" S run duct with an inline exhast fan throwing the air into a room 20' away. The HVAC guys think it will work, and I hope so!
 

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Cooling a room full of gear and people is a real issue. Sometimes in the winter I wish I could run the A/C just in the theater. If I could start from scratch and money was no issue the theater would have it's own A/C


If I was doing it over. I would at least put 2 low side air supply runs drawn off some other point in the basement and high side exhaust out of the theater. Using oval duct if needed you can get down into the walls. It probably important to establish an across the room air flow pattern. This would run independant of the home HVAC.


I would also think about exhaust for gear and projector heat.
 

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Discussion Starter · #4 ·
Wow,


Thanks for the quick responses...


From your posts, lets say I do this....


I'll run a 6" duct down each side of the theater in the soffit to the front wall. At the front wall, I'll come down two stud cavities and install cool air supply ducts at the bottom, near the top of my stage. In that I will have columns on either side of the screen, what If I extend the duct into the bottom of the columns and attach the grills at the bottom of the columns. Sounds neat and clean, but would it cause any accoustical problems...The middle of the these columns will house my front speakers.


Now, On the rear soffit back wall, I'll install two registers. I'll duct these straight through the soffit and straight through the back wall. On the other side of the back wall, which is now the into the rest of the basement, I'll construct a similar soffit. Inside this soffit, I'll install two quiet duct fans, that shoot the air into the rest of the basement.


That all sounds really clean and easy to implement...Too easy, in fact. So there must be something wrong.


How do you guys think this will look/work/and effect accoustics...Is there anything I should do to the ducting running the length of the soffit to muffle air sounds. I was already planning to thoroughly insulate these soffts. Incidently, these soffits will also house my can lighting. Any problem with running flexible ducting in with lighting cans?


You guys are great, please keep the suggestions coming!!
 

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I would keep the duct at least a few inches from the cans.


I assume you will be drawing your fresh air from a different area than your exhaust. Putting a few "S" curves into the duct will help quiet them. I would use bigger duct for the long non-powered supplies than the powered exhaust. I think your noise concern should be centered on your fan choice and mounting location.


Otherwise I think your OK.
 

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I wish I had your problem... :) My basement HT (with LCD PJ and all the associated audio gear) stays a chilly 65ish all year around, too cold for my wife. We're installing hot water based baseboard heaters.
 

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Discussion Starter · #7 ·
Quote:
Originally posted by livitup
I wish I had your problem... :) My basement HT (with LCD PJ and all the associated audio gear) stays a chilly 65ish all year around, too cold for my wife. We're installing hot water based baseboard heaters.
That indeed may be my problem too....We've only been in the house since January, so I haven't experienced a summer yet. Our temperatures here in NC should only be slightly warmer than yours. I'm just trying to be a bit prepared for the worst. With baseboard heaters, how are you circulating the air? Won't you still suffer from CO2 buildup and everyone falling asleep? :)
 

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Nope,


I'm installing a hot water - radiant heat system. No CO2, no unscheduled naps. It's a pretty cool system that I heard about here first. You basically have a small pump which circulates hot water thru baseboard units. The basebords radiantly cool the room. No fans, no noise, except the pump, which can be installed just about anywhere, far away from the theater.
 

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Discussion Starter · #9 ·
Well, I'm referring to the CO2 from people breathing....If you are like most of us, you are building your theater like an aquarium. No sound in/out, no air in/out. How are you going to vent the CO2 buildup from people's breathing?
 
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