Greetings Malc, thats an interesting question that probably has no good answer. If you are comparing two equally leaky buildings in Warm Vs Cool climates, I dont think either climate has the advantage. Its more about where the air leaks are infiltrating from and what damage the exfiltrating air is doing on its way out.

Its possible that in extremely cold weather, the stack effect would be driving more air exchange between two equally leaky buildings. This may seem healthier but if the air is coming from a vented crawlspace, slab cracks, the garage, or wall cavities with mold/mildew problems then the air could be worse and more likely contributing to rotting the roof/attic on its way out.

In all climates, building tight with blower door tested verification and introducing outdoor air with mechanical ventilation is the direction of what most consider smart building.