Ask for the real supply position at the site: hours of grid supply, voltage stability and the longest recent outage. The design must survive the worst of those, not the average.
A band of 14 to 18 °C has very little room in it. When power stops, the room drifts towards outside temperature within hours, and NHB's ceiling of 26 to 27 °C can be crossed in a plains summer before a generator is arranged.

