Tips for Renting Portable Heaters

Things to consider before you rent

Renting portable heaters to warm an office, retail space, event tent, indoor construction site or manufacturing or industrial facility can be less straightforward than you might think. 

“Most people just think ‘heat,’ and they don’t consider all of the factors that might go into sizing a job,” said Brian Sloat, a United Rentals branch manager with the Climate Solutions group. 

Understanding the space you need to heat, the type of heater that might suit your needs, and the maximum voltage your outlets can handle are among the challenges of choosing a portable heater for your job.

Heat needs 

What ambient temperature do you need the space to be, and how much heat output do you need from a portable heater to achieve it? 

Several factors figure into answering the second question. They include the square footage of your space, the number of windows and doors, the materials of the floor, walls and ceiling, and the height of the ceiling. “Most people don’t take ceiling height into consideration — and heat rises,” said Sloat. 

The degree of insulation matters, too. If you’re heating an outdoor tent, don’t treat it like an indoor space of the same size. “A lot of people don’t consider that a tent has no insulation,” said Sloat. “That’s why you’ll go in a lot of event tents and it will be cold, or hot on the other side of the equation.” Also consider the number of people who will occupy the space; more people generate more heat. 

Qualified power and HVAC climate specialists will calculate the heat requirements of the space before recommending a temporary heating solution. They will use the insulation factors of the space’s surfaces (walls, ceilings, floors) and the sizes of those surfaces to calculate the total BTU load, then use another formula to calculate the BTU/kW of heat required. If you happen to know your total BTU load, you can figure out approximately how many kW you need in a heater. Multiply the heater’s wattage by 3.412 to get BTU per hour. A 15,000W electric heater produces approximately 51,180 BTU per hour.


“A lot of people don’t consider that a tent has no insulation. That’s why you’ll go in a lot of event tents and it will be cold, or hot on the other side of the equation.”

Brian Sloat, United Rentals Branch Manager with the Climate Solutions group

Fuel-fired vs. electric 

Propane, natural gas, diesel, electric — your selection will depend on your needs and your budget. Electric heaters generate clean, dry heat, and they do so silently. If the unit itself will sit inside, it’s the easiest choice, since it produces no exhaust or carbon monoxide. 

Combustion-powered units must be used outdoors unless you have a way to extend the flue pipe outside. If placed outside, the heat can then be ducted inside through a window, door, or other opening. 

Budget-wise, electric usually won’t be your best bet. “Diesel, natural gas and propane will be cheaper to run than electric,” said Sloat. 

A heat pump is another option if you have a way to vent the exhaust. 

As far as fueled-fired heaters and the risk of fire goes, indirect-fired heaters, in which the flame is contained in a heat exchanger, are safer, albeit more expensive and less efficient, than direct-fired heaters. 

Voltage requirements

If you’re looking to rent a heater and all you have to work with in terms of power outlets is a standard 115-volt outlet, electric won’t do the trick unless your space is small or you plan to rent multiple low-wattage heaters. For larger BTU/kW output, you’ll needanatural gas, propane or diesel heater.

A higher-voltage power source, on the other hand, will power the larger electric heaters. If you’re not sure what you have — and a lot of people aren’t — consult your engineer or electrician. 

Once you verify that you have the voltage you need for the electric heater you want to rent, make sure you have the proper breaker for the amperage. 

Determining the best temporary heating solution for any job requires a considerable amount of thought. 

Choosing a heater that isn’t suitable for your job can leave your workers or clients in the cold, blow your fuses, or worse. Choosing any appropriate heating solution starts with performing an accurate load calculation. “Otherwise you’re just throwing a heater at a problem and you don’t even know if it’s going to work,” said Sloat.

For assistance in assessing your temporary heating solution options, contact United Rentals Climate Solutions.

Marianne Wait is an editor and writer who creates content for Fortune 500 brands. 

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