It was bugging me that I was using warm indoor air for combustion air. Cold air must enter the house somewhere when air is going up the chimney, correct? I built an outside air intake out of junk basically. The box has a sheet metal flap inside that turns 90 degrees for infinite adjustment. It works pretty well and the lower dryer hose dances around a bit when air is going through. It's a prototype I thought I'd share.
If it ever gets cold enough down there in the south, you will find that flexible hose begin to condensate and frost up. Previous to this, had you left the window cracked open a bit? If not, I bet you notice a difference in the draft now.
Cool idea but you may want to consider researching outdoor air kits a bit. It should run level with/or to a point lower than the intake connection so that a reversal in draft wont make it into a auxiliary chimney. Not likely and perhaps you already knew this but.... Food for thought.
Thanks for all the comments. Appreciated. I'll incorporate to final design. I haven't noticed any difference in inside temps but if nothing else the control over the air intake is much better than the OEM control.
