"Air side first" Maximizing HVAC system performance should be our goal.Take ownership and wait for all the smiles that will follow.Lets give the customer 93-100% (thats an A.) of their equipments rated capacity, By insuring we dont just meet minimum code requirements, (typically a D) or worse we perform at an average typically in the lower 50% When a few system static pressure and temperature measurements are recorded measured and interpreted properly we find ee are able to calculate with accuracy +or - 300btuh the exact btuhs being delivered to the conditioned space. Lets exceed minimum code and the cheaper is better mindset that got us in this spot. Instead adopting a "best practice" approach to system redesign and renovation. Yes its possible for them to deliver, 90-100% true capacity is achievable wherever true total cost a primary factor used in determining which upgrades will be of the most beneficial. Increasing comfort, ease of use and making each customer's system the most important thing we do. improvements made (should do no harm.) the sweet spot ... 6" sq. Free air Per 1000 btus cooling