I have a shop that is a converted detached garage. Insulated and open on both ends with overhead doors. When the weather is nice I keep both doors open with a big fan blowing through. Great for cleaning out the shop with my leaf blower and looking out back at the trees while turning. That said, when the temp outside is 95, over 100 with heat index, even a fan ain't enough. Looking at portable AC units that vent to the outside with a 4" hose. Lots of options and see some with good reviews. I have 325 sq ft. I have two overhead air filtration units that can run all the time and a good dust collection system for my machines. That said, it would still need to have the filter cleaned more than if in a bedroom. Any inputs on units, brands from folks that have put one in their wood shop?