While constructing my new cellar, I selected a SC Pro Series unit for the ease of installation and affordable price point. I became concerned that the ventilation room would get too hot and the unit wouldn’t function properly. After consulting Client Services, they recommended that I go with the Extreme ti that would be able to accommodate higher temperature fluctuations, despite the increase in price. Glad I took their advice! The unit operates well even during the hottest summers. Worth every penny!