A 40 ton ac unit is a trailer mounted or skid mounted temporary cooling machine rated at about 480,000 BTU an hour, and it hires for roughly $2,500 to $6,000 a month plus delivery, rigging and the power connection. It is the size a yard sends when a building's own plant is down, a data room is at risk, or a summer shutdown has to keep running.
What a ton buys you
A ton of cooling is 12,000 BTU an hour, so forty of them is about 480,000. That is a plant sized number: it covers a large open floor, a production hall in shoulder season, or the load a failed chiller was carrying. Sizing is done from the actual heat load, not from square footage, and any yard worth hiring from will ask for it.
Three phase power, or the delivery does not happen
A machine this size is three phase, commonly 460 volt, and wants a feed and a disconnect sized well past what a site panel usually has spare. Get an electrician to confirm the available capacity before the unit is booked. Where the supply is not there, the same yard hires a generator and cable to match, and that doubles the moving parts.
Air, water or a packaged unit
Ask whether you are hiring an air cooled packaged air conditioner, a chiller feeding existing coils, or spot coolers ducted to specific areas. They solve different problems: a chiller ties into a building system, a packaged unit blows conditioned air through temporary duct, and spot coolers handle people and equipment rather than a whole space.
Access, placement and the duct run
The unit needs a firm level standing, clear space around the condenser so it is not breathing its own hot air, and a route for large diameter duct into the building. Rigging onto a roof or through a courtyard is a crane job priced separately. Walk the route with the yard before the delivery date rather than on it.
Cooling is one control in a heat plan
Where the reason for the hire is worker heat rather than a process, temporary cooling sits alongside water, shade, rest and acclimatising new arrivals. OSHA's heat guidance treats those as the primary controls. Cooling a break area properly is often a better spend than trying to hold a whole open floor at a set temperature.
Questions people ask about 40 ton ac unit
How much space will 40 tons of temporary cooling handle?
It depends far more on the heat going into the space than on its size. A lightly loaded open floor may be several tens of thousands of square feet; a room full of running equipment can absorb the whole 480,000 BTU an hour in a fraction of that. Give the yard the equipment load and the outside design temperature.
Can I run it off a rented generator?
Yes, and it is a common pairing, but the generator has to be sized for the starting current rather than the running load. Hire both from the same counter so the cable, the disconnect and the sizing are one person's responsibility instead of two.
Is it hired by the day or the month?
Temporary cooling is normally quoted monthly with a minimum term, because mobilisation and the electrical connection cost the same whether the unit stays a week or a season. Day rates exist for emergency cover and are proportionally much higher.