So I'm about to put in an air intake in the man cave as well to increase the air circulation. It will be in the opposite site of the room for the exhaust fan, but I am uncertain if I should place it high or low.

My thoughts so far is: The air coming in to the room is colder than the man cave it self. This means that it makes sense to have the air intake high, since the colder air will sink down and better mix with the air inside the room, creating a better air circulation.

Any thoughts?

maybe the opposite of the exhaust fan - if the exhaust is high put the make up air inlet low. 

I'm no specialist but I'd assume higher is better. Warm "used" air will rise and be exhausted.

Could be wrong though but t is what I have done: Intake placed opposite side of room diagonally so Intake is as far away from out as possible

Smoke rises.  As long as you are pulling the air from the outside and not from another area in your home, then placing it high would make sense.  If pulling the air from another area in the home, I would place it near the floor.

My air intake comes from the bedroom next door and is located low to the floor as the exhaust fan is on the ceiling and vents through the roof to outside. The HVAC return in the smoking room has been sealed so smoke doesn't recirculate through the HVAC system when the sir comes on in the house.

Outside air here its too damn hot in the summer and too cold in winter!

Thanks for your feedback. The exhaust is placed high, diagonally across the room.

I am pulling air from inside, but I am planning to use one of these (see image) on the man cave side. I'm hoping this will serve two purposes;
1. Allow the man cave to still have negative pressure even if the exhaust fan is running on low speed and only open when needed.
2. Stay closed when the exhaust fan is not running, thus not allowing smoke or smell to seep back into the room I am pulling air from.

One advantage of placing the intake low is that it will pull inn the coldest air from the next door room, but one major disadvantage is that no shelf's or furniture can be placed in that location on either side...

QuoteMojo66 - 4/24/2015  12:07 PM  I'm no specialist but I'd assume higher is better. Warm "used" air will rise and be exhausted.  Could be wrong though but t is what I have done: Intake placed opposite side of room diagonally so Intake is as far away from out as possible

Forget this, I did read Intake in your question but my brain registered the opposite so I was obviously talking about getting air out of the room and since that wasn't what you were asking, I'll just shut up now

I would place it as low as possible and opposite the exhaust, also if possible the intake should be 1.5 to 2 times the size of the exhaust to provide a smoother in take and mixing with existing air in the room.

If the louvers on the vent DO NOT SEAL TIGHT, smoke WILL seep around them.  You could use a flush grate on the other side of the wall so as to allow furniture, etc. to be placed in front of it.  As long as air can flow to the grate, you shouldn't have any trouble.

QuoteLonghorn - 4/25/2015  1:42 AM

If the louvers on the vent DO NOT SEAL TIGHT, smoke WILL seep around them.  You could use a flush grate on the other side of the wall so as to allow furniture, etc. to be placed in front of it.  As long as air can flow to the grate, you shouldn't have any trouble.

Thanks Brad, I'm quite sure it doesn't seal 100% so intake by the floor it is :)

Quotentanner - 4/25/2015  12:35 AM

I would place it as low as possible and opposite the exhaust, also if possible the intake should be 1.5 to 2 times the size of the exhaust to provide a smoother in take and mixing with existing air in the room.

I'm planning on keeping it the same size to make sure I have enough suction to keep the room negative pressure. There are openings here and there where air comes in :)

Quotehebron - 4/25/2015  2:35 AM

Quotentanner - 4/25/2015  12:35 AM

I would place it as low as possible and opposite the exhaust, also if possible the intake should be 1.5 to 2 times the size of the exhaust to provide a smoother in take and mixing with existing air in the room.

I'm planning on keeping it the same size to make sure I have enough suction to keep the room negative pressure. There are openings here and there where air comes in :)

If you have a fan on the exhaust you should still be able to maintain negative pressure with a 1.5 to 2 times larger intake, the difference is how much turbulence and  intake noise but if you have other inlets into the room going with the same size should work.

Pictures when done, please!  

Intake is ready :)

I placed it low as you suggested. I did some tests with the self closing louvers vent thing, but it didn't perform as I wanted. It took too much force to get it to open so the air flow was severely restricted. So I installed a regular vent instead.

The intake is 100 mm, while the exhaust is 125 mm. I did this because there are some additional cracks here and there that let air in, and the negative pressure when smoking is very important. Plus I normally have the extraction fan at low speed.

After putting in the air intake the extraction fan is much more efficient is lowering the temperature, so it seems to do the trick :)

Looks good.
Nice job!

Very nice.

That's pretty sweet. How about pics of the rest of the room?

Nicely done, Thomas.