Air conditioning a home theater.

There are other alternatives to consider that are less expensive too. Without knowing your house layout (1 story or 2, location of room, etc) I'd venture to say the carpet and drapes present NO problem at all. The drapes probably BLOCK heatflow through the window, if it is on a southerly-exposed wall. If so, even planting a diciduous tree of the correct size by the window will help with the cooling.
Also, you could divert MORE of the AC TO your AV room and let your other(s) room warm up more, if your lifestyle would allow that. That can be accomplished by having an AC tech install dampers in the ductwork, allowing you to direct the flow to the rooms you choose.
Hope that helps or gives you some ideas.
Good Listening & L@@king!

Marc, Zone the house, use acoustic rigid duct for this room. Your HVAC contractor will know. Up the tonnage. This will cost a few dollars, but depending on the age of existing unit, utility bill will drop. You will also need a door to this room. Having common supply or return defeats the purpose. Z.

whats wrong with a simple window air conditioner?

Bigjoe, Noise is what's wrong, both audible and electrical.

Marc, a couple of questions:

1.) Was the room adequately cool and comfortable in past summers before the recent conversion? I'm guessing 'yes', because . . . . . . .

2.) There appears to be a fairly large supply register on the wall above your TV. Is there a return air register somewhere else in the room? I'm guessing 'no' because . . . . . . .

3.) The supply air probably originally found its way back to the A/C fan through the (now closed up) opening, via a return air grill somewhere else in the house (a central location, like the hallway.) Am I correct?

If I am correct, you need to 'uncork' the room in some way, because the supply register is now trying to 'pressurize' the room, and it cant, so little or nothing comes out of it. There are a number of ways to fix this, and I'd be happy to list them, but here's one that (after looking at your setup) will both keep your room cooler AND keep any component heat out of the room (and keep the components cool too!):

If the closet behind your equipment has another wall (or door) which adjoins a space that has unobstructed access to the main return air register (like the hallway), then all you need to do is install a "transfer grill" in that wall, preferably up high, or above the closet door, so hot air won't collect in the closet. (A transfer grill is just a hole in the wall with a grill on each side to dress up the hole.)

If that is not possible (no adjoining wall in the closet) but there's an attic space above the closet, then install a grill in the ceiling of the closet and run a duct from that grill to the main return duct of your system. It will work just as well, but will cost a little more.

(Make sure any return air grill and duct have at least 1.5x the area of the supply grill and duct.)

Anyway you should be able to do some version of this, and it should solve the problem. With the additional feature that your components will be cooled and won't add any extra heat to to room.

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