new room design-10'x20'x8'-ventilation

restlesswynd

Active Member
Howdy, I helped a friend build a new room and wanted to get some feedback on ventilation.....

We built a 10'w x 20'l x 8"h room within a garage. There are (2) large 12"x 24" vent grills on either side of the garage mounted high into the pitch of the roof. there are also (4) other smaller vent grills, (2) on the front side and (2) on the back side under the eave that measure 4"x14"(not the same size as your central heating/ac grills in your house). Insulated with R19 and sheetrocked. The floor is concrete.

Our thoughts are this.....we only want to use the 2 smaller vents on the rearside and (1) of the larger vents up near the apex of the roof. Don't want to use the other large vent because it faces towards the road(fairly far away, but sketchy nonetheless) and we don't want to use the (2) smaller front vents because they face the driveway as you pull up and walk to the front door. We can't cut any holes to allow for more venting options.

It will be an 8" can fan with a can100 carbon filter for exhaust and a passive 10" or 12" intake. No a/c or light cooling will be utilized.

We are thinking of using the 2 smaller rear side vents for the exhaust as it points away from the house/driveway. Goto Home Depot and find the right sized grills with an 8" flange on the rear to hook up the ducting. So, it would go- filter --->fan--->ducting--->Y adapter to split the single 8" duct into 2 for the 2 small rearside vents--->grills.

Question: Do we need to split the exhaust into two ducts to utilize both vents? I am unsure if (1) of the 4"x14" vents is sufficient for an 8" duct. Fan is rated at 650cfm (or somewhat close), plus sucking air thru the carbon filter, so that figure drops down a bit in drag. If I only use one, that frees the other one up for the light cooling(if employed) which brings me to my next question. Say you have 4,6,8,10, etc lights (HID) and they are set up in two rows. Each row will get it's dedicated intake duct( or can I bring one fresh air duct into the room and Y into 2??) , but on the exhaust side, can you Y those ducts together into a 6" or 8" fan to have only one exhaust duct for both rows of lights or do I need to keep them separated and run two seperate exhaust fans and ducts??

As for the passive intake, I planned on running the 10" ducting from the larger vent located towards the apex of the roof down into the room.

We decided to use the larger vent for the intake as it faces the house(and the other one faces the road), so to keep the room quieter from the outside, it just made sense to run the exhaust out of the rear of the garage. His closest neigbor is 2 acres away so they can't/won't hear the ecxhaust.

No plans for light cooling as I have nowhere to vent it except into the other part of the garage. Good idea or bad idea to vent into the garage? I know it is preferable to vent it outside, but don't really have another available vent(IF I end up using both smaller vents for the filtered exhaust).

Well, what do you think? Any thoughts or alternative ideas?

:peace:
 
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