How much is an estimator looking at while preparing an assemblies estimate for the HVAC on a two-story office building of 20,000 sq. ft size? Based on the occupancy and industry standards for the area in which the office is being constructed, it is determined that 1 ton of cooling will handle 300 sq. ft of floor space. The historical cost data reveals that for projects of a similar size and type, HVAC cooling costs $5,000 per ton, including RTUs, ductwork, insulation, and piping.