A regular installation (or a change-out) is normally what people get when you’re bidding jobs, which includes the replacing of your equipment, takes 1 day, the installation turns it on, Freon levels look OK, they’re done. An ESQI follows recommended industry standards by the Air Conditioning Contractors of America, starting with load calc and you measure everything. Most houses across the country deliver less than 60% of what you’re paying for in terms of BTUs. If you have a 5 ton, you only actually get a 3 ton. So you’re wasting 40%.