Generators are hired by kilowatt, and the number people get wrong is the starting load rather than the running one. A 20 kW towable is commonly $150 to $250 a day and a 100 kW unit $350 to $600, so over-sizing is expensive and under-sizing means the set stalls the first time a motor starts.
Size on the surge, not the nameplate
Add the running watts of everything that will be on at once, then add the largest single motor twice over, because an induction motor draws several times its running current for the first second. A well pump, a compressor or a lift will do this. Sizing on running load alone is the most common reason a hired set trips under a load it should carry.
Fuel, hours and who fills it
Most towable diesel sets run 12 to 24 hours at half load on their own tank. The hire may come full and be billed on return at the counter rate, or arrive with fuel delivery arranged as a separate service. On a multi-day outage, that arrangement matters more than the day rate, because someone has to be there with the fuel.
Connecting it legally
A small unit feeds extension leads and site distribution boards directly. Anything feeding a building needs a transfer switch and an electrician, because back-feeding a panel through an outlet is what kills utility workers on the line. Larger sets terminate in cam-lock connections, so order the tails and the distribution box with the machine.
Day, week and outage pricing
Weekly rates land near three day rates and monthly near three weeks, so an outage expected to last five days is booked as a week. After a storm, availability rather than price is the constraint: regional fleets clear within a day and the sets that arrive come from further away, with the transport charged accordingly.
Questions people ask about generator rentals
What size generator do I need for a house?
A whole-house backup is usually 15 to 25 kW, while running a fridge, a furnace fan, lights and a well pump can be done on 7 to 10 kW if you accept load management. The well pump or the air conditioner compressor is nearly always the number that sets the size.
How much does a rental generator cost per week?
Roughly three times the day rate, so a 20 kW towable is often $450 to $750 a week and a 100 kW set $1,000 to $1,800. Fuel, delivery each way and the cable tails are separate lines on top of that.
Can a rented generator power a building directly?
Only through a transfer switch installed by an electrician. Plugging a generator into a wall outlet energises the utility side of the panel and is dangerous to line workers as well as to the equipment in the building.