A clothing shop taking over a unit on a busy street, nine days before opening, wanting to know how much cooling it needed with the shopfront door standing open all day.
The honest answer was that no amount of cooling solves an open door onto a street at thirty two degrees, and adding capacity would only raise the bill while the shop stayed warm. What actually works is an air curtain over the entrance and cooling sized for the space behind it, which is what we quoted: an air curtain, four units in the shop floor and two in the fitting and store areas.
The owner was initially unhappy at being told the thing he asked for would not work. He agreed to it after we went and stood in a shop two streets away that has the same arrangement, which took twenty minutes and was the most useful part of the job.
Six units and the curtain, installed over four evenings so the fit out could continue during the day, with a drawing of the pipe runs handed over at the end. The shop opened on time and the floor holds twenty six degrees with the door open, which is as good as it gets.