Fresh Air Intake

Heyo fellow rollers!

My setup is this:
4x6 room sealed pretty tight, 600 watt HPS in a sealed air cooled hood.
Exhaust Fan = 6in Vortex pulling something like 430 cfm.
Intake Fan = Cheap 6in fan from Lowes. I think the main exhaust fan does most of the pulling here.

I used to just crack the window downstairs next to my intake fan for air to enter the grow, but with winter closing in I need something different. The window open makes it cold downstairs so I decided to run 6in ducting from the window to the room. I need to warm the air up, cause it get hella cold here, so this is my plan.

A sealed box/container with a few regular incandescent bulbs inside. This will warm the air up as it passes through on it's way to the grow room. I will be using a metal bucket (5 gal I think) for the container. Here is a drawing of what I am going for.



Any thoughts or suggestions would be appreciated

add more 600 watt lights it always heats things up. why run shitty bulbs make 2 separate flowering cycle rooms to heat each other.

Cant really add another 600 right now... Even with another room, air as it enters could sometimes be -20 F. Thats not too often but we usually get some crazy ass cold snap. Usually the nights get down to about 10 F. I just don't want cold air stressing out my plants.