Temporary cooling is hired by the day from the same counters that rent generators and light towers, and the smallest useful unit is a one-ton spot cooler at roughly $100 to $175 a day. Size it by the heat you are removing rather than by the room, because a server closet and a warehouse aisle of the same floor area need very different machines.
What the yard means by a temporary unit
Three shapes cover most hires. A spot cooler is a wheeled one to five ton box with a flexible duct that blows cold air at people or equipment and dumps heat out of another duct. A portable air conditioner cools a whole small room. A trailer-mounted unit of ten tons and up feeds ducting into a building and needs three-phase power and a drop point outside.
Sizing by heat, not by floor area
The rule of thumb of one ton per 400 square feet only holds for an ordinary office. A room full of running motors, ovens or racked servers can need three times that, because every watt of equipment in there becomes heat you have to remove. Count the kilowatts of running plant, add solar gain through glass, and size for the worst hour rather than the average.
Power and condensate decide the day
A one-ton unit runs on a 115V circuit and pulls near 12 amps, so it can trip a shared breaker. Anything from three tons up wants a dedicated 208 or 230V supply, and the ten-ton and larger machines need three-phase or a generator hired beside them. Every unit makes water, so the hire includes a condensate pump or a tank someone has to empty.
Day, week and season rates
Weekly rates are usually about three times the day rate and monthly about three times the week, which makes a two-week breakdown cheaper to book as a month on the bigger units. Availability tightens in a heat wave, when the yards that hold stock run out first, so a call in June for August is worth more than a lower quote in July.
Questions people ask about temporary ac unit rental
How many tons of temporary cooling do I need?
Start at one ton per 400 square feet for an ordinary occupied space, then add roughly one ton for every 3.5 kilowatts of running equipment in the room. Where the heat source is a machine rather than the weather, size on the machine.
Can a spot cooler be used without ducting the heat out?
No. A spot cooler moves heat, it does not destroy it, so running one with the condenser duct loose in the same room makes that room warmer over a shift. The hot duct has to reach a ceiling void, a window or the outside.
How long can a temporary unit stay on hire?
As long as you keep paying, and monthly rates exist precisely because breakdowns and fit-outs run long. Anything past a season is usually served better by a monthly contract with a service call included than by rolling weekly hires.