Our basement HT room is being created by eliminating a wall and combining two smaller rooms ending up with a 17'X20' HT space. Both of the existing rooms each have a single heating/cooling drop out of the ceiling.

I'm wondering if the existing heating/cooling drops will be adequate to handle the new combined space especially the air conditioning load when taking into account the heat created by the projector and other electronic equipment equipment and possibly 4-8 people in the room? Most of the time it will be just the wife and I in the HT room though.

I do plan to put a thermostat connected in parallel to the existing thermostat in the HT room so I can attempt to contol the temperature in the HT room.

Opinions and solutions welcome!

Thank you.

Do you have any returns in the space?

Right now I am thinking of doing a passive return in the rear wall of the room, basically just an opening in that wall with a grill on both sides of the wall. This wall opens into a long hall that has an active return with a filter in it. I'm hoping this will suffice?

Sound proofing the room and sound control outside the room is not an issue.

Thank you.

You have another post that asks similar questions. My response (in the other post) was to tie your return directly into your system. If you are worried about having enough heating/cooling, I don't know why you would consider anything but tying the return in. Passive returns are not optimium.

budk,

Thanks for the input.

I realize it would be best to connect my HVAC return to the closest active return but there is no practical way to do that, it's really far away and with other complications to get to it. Because heat rises I'm considering mounting a couple of small passive vents as high in the wall as I can get them or maybe using a bathroom type fan vent(s) (a very quiet one) with a thermostat control if I can find them. I think cooling will be the main issue here if there is actually an issue.

Cooling WILL be your biggest issue.

You could do what I did, which was to put feeds from your hvac into the room but supplement that airflow with a an additional source of airflow.

In addition to my 6" feed from the system, I have a 8" duct of air coming in from the unfinished part of my basement that is typically cooler than the rest of the house. I also have a 8" return from my theater into that unfinished area. I have a 425cfm fan on the 8" return that pulls air out of the theater. Some of the air it pulls out is from the HVAC duct and some of the air is from the other 8" duct.

My point is, that you won't have much success if you only push air into the room and have a small, unducted return. Pulling air out is just as important as pushing/pulling air in.

Best of luck.

budk,

Can you tell me who makes the fans you used, are they nice and quiet? Maybe I could use them to exhaust hot air from my room and solve my problem. The whole downstairs area where my HT is is already fully air conditioned.

Thank you.

I used a inline Whisper fan made by Panasonic. It's quiet, but then again it's outside of the sealed room and at the end of a 20 ft piece of flex duct that makes at least 2, 90deg bends.... so there is no sound from the fan getting back into the room.