# Can I install a window AC unit in my theater wall?



## Rancho5 (Aug 20, 2009)

My HT is in my attic above my garage. While we have AC to it from the house (2 ducts) and an air return, it still gets warm. It's totally insulated BTW. In fact I think it's so well insulated the PJ heats up the room.

I'm thinking of installing a window AC unit into the wall because the other side is just attic space and that's got tons of ventilation. I can even see daylight every third stud between the roof and the wall. I'd frame a shelf on the back side of the wall to support it all and then just cut the drywall where the AC unit pokes through.

This would work, right?


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## robbo266317 (Sep 22, 2008)

Most window aircons are very noisy, is there any way to boost the flow of air from your main aircon, perhaps a fan inline with the duct?

If you did put it in you will need to either plumb in or collect the condensation which can be considerable.


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## bpape (Sep 14, 2006)

Generally, problems like this are a result of too little return for a high BTU situation. Regardless, I would agree with the above post that some sort of boost to either the return or supply side of the existing ducting would be a more effective solution.

Bryan


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## mrloofer (Mar 27, 2010)

Also consider a mini split system. Very quiet and efficient and reasonable price wise too.


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## Rancho5 (Aug 20, 2009)

Boosting the air return is not an option, I think, because there is no way to get power to that return. Also boosting fans inside the duct would also be impossible as there is no easily available power. Also the ducting is the 10 inch flex tube that comes off the larger square metal ducting.

Condensation is not a huge concern as we live in NM, where it is dryer than dry. A 5 gallon bucket underneath should last all summer.

I've looked at this unit http://www.consumersearch.com/air-conditioner-reviews/kenmore-76081-7800-btu because of its reviews on being quiet. 

My HT is 230 sq ft and this does 400 so i figure on low it would be fine.

Thoughts?


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## sga2 (Nov 14, 2009)

These units (not this specific make/model, but this type of system in general) are called "window shakers" in the construction industry because they are noisy. Even premium units will be much noisier than you would ever wish to tolerate in a home theater environment. You don't want to hear that compressor kicking on and off or the cabinet rattling around. These also let in a fair amount of outside noise (traffic, lawn mowers, sirens, etc.) into the room as well. These may be OK for a general living space like a play room, but IMHO are not a good application for HT but should be a last resort. 

I agree with mrloofer. A mini split would be a very good solution. These units are rediculously quiet and VERY efficient. I've never had a client that was unhappy with one. It would be relatively painless to install but you'll need to pay someone to do it unless you're a licensed HVACR contractor - probably cost on the order of $2k (including electrical) for a 3/4-ton system. You'll also need to figure out a location for the outdoor unit and get power to it, and coordinate the routing of the refrigerant lines and condensate drain (you will still need, even in NM...).

sga2


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## bambino (Feb 21, 2010)

They do make duct covers with built in fans, maybe that would work i know you mentiond the no power issue but even on low a window AC will disturb your peace.


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## salvasol (Oct 31, 2006)

I agree with trying to avoid the window unit...

Is there any way that you can hire (or do it yourself) to get power near the boxes and add an inline fan???

Maybe use an extension??? (as you can see  here  there's some that uses a 3 prung receptacle)


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## mdrake (Jan 31, 2008)

I saw one guy on here who used a window unit in a remote location and used ducks to get the air into and out of the room. This is what I am going to try. 

Matt


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## Rancho5 (Aug 20, 2009)

I've got a call into the HVAC guy who did my HT on the side. The in line fans look cool. Thanks.


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## JohnWin909 (May 25, 2010)

I have a window AC installed in the same room as my system, it is VERY VERY VERY noisy unless I leave the temp on it @ 78F or so, instead of 72F which is normal room temp.

+1 for the ducting advice.


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## sga2 (Nov 14, 2009)

If using a booster fan (or fans) just be careful that you are not going to create noise problems which would most likely occur due to fan noise or airflow noise. Keep in mind that the typical application for these is not noise-sensitive environments. Also, it is likely that the existing duct and air devices (supply/return grilles) are probably not large enough to handle the necessary airflow at low noise levels (i.e., HT environments). I would advise the following:


Try to locate the fan as far away from the room as possible. I would recommend a minimum distance of at least 5ft from the room wall and having at least 10ft of flex duct from the fan connection to the supply register or return grille (to minimize discharge noise entering room through duct system). These are minimum distances - better if you can get more.

Be sure the duct and air devices (supply and return) are sized adequately so that you are not generating noise created by high velocity and turbulence. Per ASHRAE guidelines, I would recommend a maximum velocity of ~300-400 feet per minute (FPM). Most typical duct systems are not sized this conservatively so I would be surprised if you can move enough air to satisfy the room load at these velocities - may need to do some duct changes if that is possible.

If you have a choice of 2-3 fans that can provide the airflow you need, go with larger fan/lower speed option. Might even consider deliberately oversizing the fan a bit and putting an inexpensive speed controller on it.
I'm an HVAC engineer and have used similar strategies for commercial sound-critical applications with success. However, these are just easy rules of thumb and Bryan or another acoustical engineer may have better advice more specific for HT applications.

You should also consider controlling the fan(s) via a wall switch or a thermostat so you are not robbing the rest of the floor of air when this room is not occupied...


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## goyop (May 4, 2010)

If you haven't done anything yet I have a suggestion for you. I design remote electronics/server boxes that are completely sealed and installed on roof tops and other crazy locations. There are thermoelectric air conditioners that have no compressor. They are basically an array of semiconductors that get really cold on one side and hot on the other. I used them to keep these closed systems under 85 degrees f. They cost a little more than a window mount AC unit but the only noise is from a cooling fan and they work like a charm.

Greg


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## MatrixDweller (Jul 24, 2007)

You can buy portable room air conditioners that hook up to a window via a hose to exhaust the warm air.

Another thing to consider if you do decide to mount an air conditioner in your wall is that they need to exhaust the warm air out to remain cool and not over heat. You would want one that is meant to fit inside a sleeve and not a window. Window AC units typically have vents on the sides and if you block them the unit will overheat.

The other option as another person mentioned is a split unit. They are quiet and double as a heater in the winter months.

You might also want to consider insulating and sealing your walls and attic and installing vents in your roof.


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## ironglen (Mar 4, 2009)

MatrixDweller said:


> You might also want to consider insulating and sealing your walls and attic and installing vents in your roof.


I just blew insulation in my attic last weekend. It had 6-8 in, and now has 12-18 in which is closer to recommended. I also cleared the exhaust vents by using a jigsaw to clear the opening better: it effectively doubled the flow capacity. I am also installing more under-eave vents to allow more flow.


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## MatrixDweller (Jul 24, 2007)

ironglen said:


> I just blew insulation in my attic last weekend. It had 6-8 in, and now has 12-18 in which is closer to recommended. I also cleared the exhaust vents by using a jigsaw to clear the opening better: it effectively doubled the flow capacity. I am also installing more under-eave vents to allow more flow.


That'll save your shingles too. 

There's nothing more frustrating than having to re-roof after 8 years when you used 25 year singles. My parent's house is like that even though it has more than adequate venting.


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## salvasol (Oct 31, 2006)

ironglen said:


> I also cleared the exhaust vents by using a jigsaw to clear the opening better: it effectively doubled the flow capacity. I am also installing more under-eave vents to allow more flow.


Want more flow??? ....install an attic fan :innocent:

I installed one, but sometimes I think is a little noisy.

This is similar to what I installed http://www.homedepot.com/Master-Flo...splay?langId=-1&storeId=10051&catalogId=10053


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## chiltown (Jun 29, 2010)

Don't bother with window mounts and consider spending the extra money on a heat pump as a wise investment.


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## ironglen (Mar 4, 2009)

salvasol said:


> Want more flow??? ....install an attic fan :innocent:
> 
> I installed one, but sometimes I think is a little noisy.
> 
> This is similar to what I installed http://www.homedepot.com/Master-Flo...splay?langId=-1&storeId=10051&catalogId=10053


I bought one of those! But I took it back:scratch: We have cold winters here, but more days with heat: it uses electricity too, so I was on the fence. 

The builders really didn't install enough vents, in fact, the homes around me are all under-ventilated: not even close to spec. I didn't want to put a fan in since we have a new roof and I'd have to wire it in too. I should have had the roofers put it in:doh: For the $50-60 cost, I opted to blow additional insulation which would help year-round, but it's still very hot up there.


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