I'm framing out a wall for the theater in my basement, and spacing it about two feet from the concrete wall, for a space to keep all my networking and some a/v equipment, as well as easy access behind the theater wall. There will be a door on the front of the wall for access.
My question is do I need to insulate the cement wall in this space? I'd rather keep it cold, simply to help with cooling of the equipment but I'm worried about a big cold wall letting in the cold during the winter. Or will the 2 feet of dead space act as insulation?

I plan on doing either some passive ventilation to exhaust hot air from the equipment, or putting in an exhaust fan, haven't decided yet. Do I need to insulate this space?

 

The wall temperature may not be subject to too much change over the seasons, due to geothermal conditions below grade. However, allowing it to become a cold wall and the heat from the equipment, you may be setting it up for a good amount of condensation. Securing XPS to the walls and sealing with tape will help, as will an exhaust fan. Just exhaust it to the outside.

 

OK that's not a bad idea. Exhaust outside you say? Hm, hadn't considered that, just because I didn't want to go to the trouble. Was thinking of just exhausting it into the next room. (office space)

 

Why intentionally direct possible moist air into a controlled temperature room? I'd go outside if there is any possibility.

 

Ha well I didn't realize it would be that moist. I just imagine exhausting warm clean air out into the house. I guess you're right. I'll look into venting it outside.

 

Chandler is absolutely correct about the temperature below grade is much warmer due to geothermal effects. The cooler temperatures, however, can cause moist air in a void space.

The mythical "frost depth" is an indicator of how cold the soil may be. However, the actual soil temperature is rarely (or impossibly) as low because the "frost depth" is the maximum depth over a long period (50 to 100 years) that can actually cause structural damage to a structure depending on the soil type. - I was on a construction site after over a month and a half of cold weather (daily lows of -0F to -40F and never above +5F during a "hot" day". We were excavating for a new road and found the frost down to less than 6" with only 8" of snow cover, so it shows that soil thermal capacity and minimal ground cover are very effective.

Dick

 

So if I do insulate, then it shouldn't get too cold in there, thus not as important to exhaust outside?

 

I'll agree with that. If all you have is audio equipment, the heat generated may not be too much, and a chassis fan could be used to move the warmer air so it dissipates better.

 

Yeah really all I'm going ot have back there is my 24 port switch, and my Comcast modem. The theater wall will have built in shelving that will hold a few things like my receiver and ps3 that will be exhausting back there, but that's it really. I'll make sure to have good air movement and try some passive venting first. I think that should do it, but I will keep an eye out for excess moisture. I even have a little thermometer with humidity sensor I'll put in there to monitor for a while. If I have to vent outside later on, it won't be any harder after its finished than it is now. Cause this space won't be finished with drywall. Thanks for the advice.

 

So in planning my ventilation, I may just go with passive venting with a vent on the wall above the A/V cabinet, but I may like to go with a small very quiet bathroom exhaust fan inside the room, venting to the main room, and was curious about your thoughts on this. Having already discussed the possibility of venting moisture into other rooms, I think we can ignore that for now, especially since the room I'm venting into is 42' x 17', almost 800 sq feet. So pretty large room.

Anyway, here is a sketchup of my screen wall, and you can see the vent above the A/V cabinet. The bottom of the door will have a gap, allowing for cold air return.
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And here is a shot from behind, I will probably just passively vent the cabinet, with holes on the back and top, but this shot has some 120mm fans as a possibility. Then it shows the bathroom exhaust fan going out to the wall. I would get a very quiet, low power fan, (Seeing as I'm only venting 34 sq. feet), but still I figure mounting it this way should keep it virtually invisible to the ears when out in the theater room.
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Thoughts?

Edit: This cooling fan says it moves 50CFM, which is the same as the smaller bathroom exhaust fans, I suppose that would work as well, albeit a bit less complicated than the bathroom exhaust fan setup? I dunno, seems like it would be better to put directly on my a/v cabinet, with a stronger fan for the main room.
Edit 2: Yes, that definitely would be under powered or the whole room.