Timothy, I actually like the walk-in cooler idea, but only if you treat it like an insulated shell and not like a cooler you are trying to run as-is. The upside is real: insulated panels, washable interior, tight envelope, fast build compared to framing a new room. For a 15 x 23, that can become a very workable fruiting room. The places I would check before buying: - Condition of the panels, seams, floor, and door gasket. Any hidden organic buildup becomes a long-term contamination problem. - Drainage. You need a clean way to handle washdown and condensate. - Fresh air exchange. The cooler box will not solve CO2 by itself. Plan intake, exhaust, filtration, and fan control from day one. - Humidity distribution. Do not just blast fog into one corner. Think circulation, wet surfaces, and where water will collect. - Cooling equipment. If you are fruiting warm-weather species, you may not need the refrigeration system much. If you do use it, watch condensation and short cycling. - Electrical and penetrations. Every hole through the panel needs to be sealed properly. My take: good idea if the box is clean and you budget for airflow, humidity, drainage, and controls. Bad idea if the low price makes you skip those retrofits. Before you buy one, I would sketch the air path: where fresh air enters, where stale air leaves, where fog/humidity enters, where water drains, and where racks sit. That drawing will tell you if it is a bargain or a future headache.