This is the harsh truth:

This is the harsh truth: most HVAC failures take place because someone missed a step. Failed to calculate the load properly. Used cheap equipment. Miscalculated the insulation needs. We have fixed countless of these failures. And every time, we file away another learning. Like in 2017, when we decided on adding smart thermostats to each system. Why? Because Sarah, our lead tech, got sick of watching homeowners lose money on poor temperature control. Now clients save 20-30% yearly.
https://www.houzz.com/hznb/professionals/home-automation-and-home-media/product-air-heating-cooling-and-electric-pfvwus-pf~1742073236