What up DGC! Not sure how much of a hack this is, but a simple fyi.
I assumed my vent-less garage heater put off co2, but wasn’t sure so got a meter, and viola! By utilizing my garage heater to just keep the temp in the garage around 60 I get to enjoy PPM’s of the 1200-1800 range consistently during the winter months. It’s an insulated garage and garage door, finished drywall etc. Love the show, it’s entertaining and definitely educational, so happy to support it!