HT & Air Flow Problem *Fix*

Discussion in 'Home Theater Projects' started by Erik Farstad, Sep 11, 2003.

  1. Erik Farstad

    Erik Farstad Supporting Actor

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    You all may remember how my HT room has a register but not a fresh air intake...and how I discussed how to keep the room at a decent temperature especially given the extra heat our new projector throws off. Well, I could just crack the door, the window, etc...but I still wanted to do something...so here's what I've come up with:

    First I'm gong to punch a hole in the wall that adjoins the family room in the basement.

    I'll attach one of these [​IMG] to the outside wall. The rectangle opening will face the theater room.

    Then I'll connect some flexiduct [​IMG] to the fitting attached the the wall.

    After about 2-3 feet or so I'll install this inline duct booster [​IMG] that will draw the air from the theater room, which I will then vent into the family room.

    I'll then cover both openings with one of these [​IMG] painted to match the wall color.

    To power the inline duct booster, I just have to run normal 120 to it which I can branch off from our existing wiring in the ceiling.

    To turn on/off the duct fan I'll install one of these [​IMG] that I'll be able to control with my X10 gear! [​IMG] It's an inline relay that allows you to turn things on and off without a hard wired switch!

    So basically I'll be able to hit a button on my remote that will turn on the fan, pulling any hot and stale air out of the room!

    All of this will be built in a soffit on the family room wall, mirroring the other soffit on the adjacent wall that already houses duct work...so it will be nice and balanced! 8)

    I'll of course be documenting every installation/construction step on my website, but I'm just happy to have finally found a solution other than cracking the door!

    E
     
  2. Ron-P

    Ron-P Producer

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    Erik, very cool indeed. I am really interested in the inline relay, where are you picking that up?

    I am having a similar cooling problem but only when the theater is full of people. Below is a crude layout of my room I worked up with the paint program.
    [​IMG]

    The AC unit I have on the floor in the front spits out cold air and also intakes the warmer air. Because of the rooms design and location of the PJ and seating, the back of the room is trapping the hot air and the AC unit cannot get cooler up there.

    I recently installed an 8" exhaust fan at the top of the ceiling in the back in an attempt to remove the hot air and pull the cooler air towards the back. It works fairly well, but now I've got two units pulling out the hotter air with only one cool air intake. What happens is the exhaust fan drops it's cfm's substantially when the door to the HT is closed and the room is sealed off.

    I need to add an external intake somewhere that will allow me to pull in air from the outside which will allow for better air flow for the exhaust fan. I just don't know where or how to add the intake vent.

    As of now, my thoughts are to add a small vent just above the AC unit to the outside. This will allow for much better air flow through the entire room, from front to back. Needless to say, this last week I've been burning major brain power trying to resolve this issue.


    Peace Out~[​IMG]
     
  3. Erik Farstad

    Erik Farstad Supporting Actor

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    Ron, the inline relay I'm getting from Smarthome

    I think one of these inline duct fans is your ticket...which would allow you to pull air in! [​IMG]

    E
     
  4. Cary_H

    Cary_H Second Unit

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    Ron....where is your exhaust fan dumping to?
    Is your AC unit a window shaker?

    Here's what's happening. Once you close the door the fan is simply pulling vacuum. (no air in, so no air out)
    When you open the door you give the fan a source of air. The problem here is that it simply short-cycles at the back of your room and is of little help.
    You need to put a transfer duct up at the front of the room near your AC unit to introduce air into the room that you're only getting now with the door open. This will create a front to back draft through your room, and will move the cooler air from the front.
    Ultimately it would be preferable to circulate the air around the room rather than exhaust air you just cooled, but a fan probably isn't something you'd want wailing away in your HT.
    Keep us up to date.
     
  5. Cary_H

    Cary_H Second Unit

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    I just re-read your post.
    Remember if you draw air from outside you'll have to heat/cool it. This "new" air is also not the same as air already in your home. It will need a way out. Air brought in from an adjacent room is preferable.
    In addition, a fan on the exhaust is all you'll need. If anything, when you're all done, you'll likely be looking to reduce airflow.
     
  6. BenSC

    BenSC Stunt Coordinator

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    That brings up a good point.. in an off manner. He's not bringing in air from the outside, I don't think.. But where is the extra air going to come from as you are sucking air into the living room? Or is that what you meant by "register, but not 'fresh air intake'"?
     
  7. Erik Farstad

    Erik Farstad Supporting Actor

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    Ben, fresh air comes in from the register and would leave via the return I would install as described above...sorry, perhaps I did not use the right words/explaination!:b

    E
     
  8. Ron-P

    Ron-P Producer

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    You nailed it Cary.

    The exhaust fan dumps the air into the garage (there's about 6' of space between the HT and the garage wall). The AC unit sits about 18" in from the garage door. I crack open the garage door about 1' to allow fresh air to circulate around the AC unit.

    What I will do, it place a vent just on top of the AC unit to the outside. This will allow the exhaust fan to move air completely through the theater. The nice thing is it will mix the air with the outside and thus the AC air will not be nearly as cold. Another bonus is living by the beach, the outside air, even during summer days, is cool so I won't have any problems with hot air being pulled in.

    During winter time, I won't even need to use the AC unit and I can just open the vent to the outside and circulate the cool outside air through the theater. I only use the AC unit during summer months and only when the room is full of people. Heck, if this works, I may not even need to use the AC unit at all. The intake vent and the exhaust fan may do the trick alone.

    This weekend I'll cut in the vent and see how it all works.


    Peace Out~[​IMG]
     
  9. Cary_H

    Cary_H Second Unit

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    When you install the duct to bring in the air you require watch that you don't position it where it might re-introduce the expelled heat dumped outside by your AC unit.
     
  10. Rik P

    Rik P Stunt Coordinator

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    I'm sure you have thought of this Ron but why not tap off from your Main House AC and run a small duct to the room. You can always close the vent when not in use.
    I have a two car garage with an extra one car garage built onto the side of the house that was made into a room. I use this this a dedicated HT now. The builder ran a couple of small ducts like 8" or so to room. It cools just fine and i don't even notice the difference from the rest of the house whe the vents are open, so i just run the vents open all the time like it was just any other room.

    FYI. Oh yea if anyone is needing a quiet fan I bought one of those Silent Force Black&Decker stand fans (they come in black) I cant even tell its on even when its set to high. Good for HT use

    Rick
     
  11. Rik P

    Rik P Stunt Coordinator

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    Erik, I was thinking of doing something like that to my HT room. I was planing on using a AC current sensor clamp on the PJ power cord tied to a 120 volt relay. So basically when I turn the PJ on the fan kicks on automatically. I was planning on dumping the hot air in the addict.

    Rick
     
  12. Ron-P

    Ron-P Producer

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    Cary, thought about that already and the planned duct will be far enough away.

    Rik, I don't have AC in my house, just central heating. Living a couple miles up from the beach, AC is not needed.


    Peace Out~[​IMG]
     
  13. Legairre

    Legairre Supporting Actor

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    Hey guys I have a question but it's more heating than cooling related.

    My theater is heated with two vents run off the upstairs forced air system. My problem is getting the heat to circulate from the ceiling (where the vents are) to the floor. My current plan is to get some radiant heating panels that drop into the suspended ceiling grid and look like the current panels. There as easy to wire as a light fixture and just need a thermostat wired in line .radiiant ceiling panels

    Now you guys have me thinking that maybe all I need to do is use a blower(installed in a wall about 12 inches off the floor) to draw the air down from the ceiling and run a flexi tube out to the garage. Any idea if this method will get the air down from the ceiling? If it won't I'll just get the radiant ceiling panels which might be better than bleeding off the upstairs heat anyway.

    Thanks
    Legairre
     
  14. Cary_H

    Cary_H Second Unit

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    Ron....this AC unit of yours. This isn't a simple window unit you have sitting in your room, right?
    Where is the expelled heat going?

    Legairre.....you don't state how large a room you have. However, if your system is adequately sized for your home and balanced to deliver a large enough volume of warm air to this room you shouldn't have a problem.
    When your system's blower is running, are you getting an adequate volume of air being REMOVED from the room?
    Once again, air in = air out. Those registers won't do the job if asked to push into a room with no return air.
     
  15. Legairre

    Legairre Supporting Actor

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    Cary,
    The room is 13x24. That's exactly the problem. No returns. That's why I'm wondering if adding a blower to get air out of the room will help. If it won't then I can go with the radiant panels since radiant heat, heats objects and not air. Apparently they will heat everything right to the floor and I wouldn't have to worry about airflow.
     
  16. Ron-P

    Ron-P Producer

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    Cary, it is a window unit. Here's a pic of the theater that will self-explain how it's setup. I crack open the garage door and the expelled heat goes right outside.

    http://home.earthlink.net/~peregrine...odexterior.jpg


    Here's an update...Just above the AC unit I cut in a 2"x24" slot.

    On the outside of the theater, I enclosed the opening with ducting I built from 2x4's and OSB (so it all matches the existing exterior). There are two intake ducts, each about 5' long extending out from the center of the AC unit and each extend to the far side of the theater walls. From there, the ducting makes a 90 degree bend towards the garage floor. This give me plenty of distance away from the hot air expelled from the AC unit and allows the intake of the cool outside air. Also, having several 90s worked intot he ducting allows almost no light to enter and no sound to escape. The ducting is all painted black on the inside as well.

    On the inside of the theater, I am going to install a 2"x24" louvered register. The opening is squeezed in just below the center channel and above the AC unit. It is completely hidden and cannot be seen from the inside of the theater.

    It's all kind of hard to explain, I'll get some pics up when I'm done.

    As for how it works, perfectly. The 8" exhaust fan draws so much air through the room I have to set it to the slowest speed possible. My wife and I sat in and watched The Core the other night and all we did was run the exhaust fan, didn't even turn the AC unit on.

    Currently, I have the exhaust fan mounted inside the back wall of the theater, which, during quiet movie scenes you can here it running. I plan to remove the fan, install about 10' or so of duct and re-install the fan at the end of the ducting. This should cut out the fan noise all together.

    So far, so good. I could not be happier with the way it's working out.


    Peace Out~[​IMG]
     
  17. Cary_H

    Cary_H Second Unit

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    Legairre....You already have a blower. It's the fan in your furnace. You just need to ensure there is an adequate return path back to it from your HT room to induce a draft.
     
  18. Tommy_C

    Tommy_C Stunt Coordinator

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    Erik, how loud is the fan? I have a basement HT and two vents for heating. My wife always complains that we need more fresh air or movement in the room if we have a couple of people in there. This just may be the ticket. My only area for the vent is down low but it still should move air around?

    Also I take it you can get those at any Home Depot.

    Thanks TC
     
  19. Erik Farstad

    Erik Farstad Supporting Actor

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    Tommy, I bought two 8" inline duct fans...they have not arrived yet. I bought them from HomeDepot.com...best price going. So I don't know how loud they are, but I plan on installing them a little ways from the intake vent and will also put in a few 'turns' to limit the amount of sound that will travel back into the theater. I will also wrap sound board around the soffit to further limit sound.

    I'll let you know when they arrived...my relay just arrived today so now I'm just waiting on the fans! [​IMG]

    E
     
  20. Tommy_C

    Tommy_C Stunt Coordinator

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    Hey Erik, have the fans got there yet and if so how did it work? Any noise?

    TC
     

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