After reading this article and all the comments, https://www.greenbuildingadvisor.com/article/how-to-provide-makeup-air-for-a-wood-stove, I’m now very concerned by the makeup air vent that was installed to my fireplace, a 4″ vent connected to the bottom right side that is wide opened (see picture). I thought the damper on the fireplace was basically closing/opening that vent but this is not the case at all and now hearing this could be a fire hazard, and a fireplace really needs only 15-25 CFM, I think I will disconnect it…

My new house will be very, very tight (still need to have the blower door test), I’m thinking of converting this vent as a hood range makeup air with a motorized damper and inline fan, controlled by a sensor on the range chimney. I know 4″ will not provide a lot of CFM but not intending to have a powerful hood range either. The fireplace is maybe 15 feet away from the hood range. Do you think this is a good idea? What about using the same makeup air vent for the dryer (I get I could not use both the dryer and range hood at the same time)? Maybe also add a switch nearby the fireplace to open the damper just to provide some makeup air when starting a fire instead of opening a window? Any expert opinions are welcome!