Can a portable generator power a whole house?

Almost never. It can power selected circuits through a transfer switch installed by an electrician. Whole-home coverage usually starts around 20 kW and moves you into towable or standby equipment.

How long can a portable generator run continuously?

Until the tank empties, which is typically a matter of hours rather than days. For continuous multi-day power, diesel equipment with a large base tank is the better fit.

2 - 15 kW · Gasoline, propane or dual fuel

Portable generator rental

A portable unit is the smallest thing worth renting: two people can move it, it plugs into cord-connected loads, and it runs a handful of circuits rather than a building.

Where this category fits

Best uses

Riding out a short residential outage on selected circuits
Hand tools and lighting for a one or two person crew
Market stalls, small trailers and remote cord-connected work

Poor-fit uses

Central air conditioning, well plus HVAC together, or whole-home coverage
Continuous runtime measured in days without someone on site to refuel
Anything three-phase, or a temporary panel feeding several trades

Typical power range

Roughly 2 to 15 kW. Treat that as the band the category covers, not as a promise that any one unit will carry your list — two 7 kW units can behave very differently once motor starting is involved.

What a portable generator realistically powers

At 2-5 kW you are covering a refrigerator, lights, phone charging, a sump pump and a couple of hand tools at a time. At 7-15 kW you can add a well pump, a small window HVAC unit or a compressor, as long as they do not all start at once.

The limit is rarely total wattage. It is the starting surge of the largest motor on the list, which can be three to seven times its running draw.

Fuel and runtime

Gasoline tanks on portable units are small, so refuelling every few hours is normal. Dual-fuel units let you run propane from a standard tank, which stores longer and starts cleaner in cold weather but gives up some output.

Refuelling means shutting down and letting the unit cool. Plan for that gap if the load matters.

Connecting one safely

Cord-connected use is what these are designed for. Powering house circuits requires a transfer switch or interlock installed by a licensed electrician; plugging a generator into a wall outlet backfeeds the utility line and is both dangerous and illegal in most places.

Portable engines are never run indoors, in a garage or under a covered porch. Carbon monoxide from a small generator can be fatal in minutes.

Fuel, runtime and refuelling

Small tanks mean refuelling every few hours, and refuelling means shutting the engine down and letting it cool.

Dual-fuel units run propane from standard cylinders, which stores far longer between jobs but usually derates output.

If nobody will be on site overnight, a portable is the wrong category regardless of the wattage figure.

Noise and emissions

Open-frame portables are the loudest thing in the category for the power they make, and they get louder as load rises.

Exhaust is the safety issue, not the noise one: carbon monoxide from a small engine can be fatal indoors, in a garage or under a covered porch within minutes.

Portability, towing and placement

Two people can usually move one, so placement is flexible — but it still needs open air, clearance around the cabinet and a level surface.

Keep it well clear of doors, windows and air intakes, and downwind of anywhere people are working or sleeping.

Delivery, setup, cable and grounding

Ask these before the unit is scheduled. Each one changes either the price or whether the job works at all.

Is delivery included or is this a counter pickup?: Many portables are collected by the renter, which changes your vehicle and timing plans.
Which cords and adapters come with it?: Household extension cords are not rated for sustained tool loads.
Who installs the transfer switch or interlock?: Powering house circuits is licensed electrical work and is never included in the rental.
How is the unit grounded?: Bonding and grounding requirements differ between cord-connected and system-connected use.

What to tell the rental provider

Every item you want to run and which of them run at the same time
The largest motor on the list and how it starts
Whether you need house circuits powered or only cord-connected equipment
How many days, and whether anyone is on site overnight
Where the unit will sit and how far it is from the load

Portable generators at a glance
Output	Typical loads	Usual fuel	Practical rental window
2 - 3.5 kW	Fridge, lights, phones, small tools	Gasoline / propane	Days
3.5 - 7 kW	Adds sump pump, small compressor	Gasoline / dual fuel	Days to a week
7 - 15 kW	Adds well pump, window HVAC, welder	Gasoline / dual fuel	Days to weeks

Build a load list before you call, including the biggest motor
Run it outdoors, well away from doors, windows and vents
Use correctly rated extension cords, not household ones
Ask who supplies fuel and whether it comes back full

Don’t

Plug it into a wall outlet to power the house
Refuel a hot running engine
Assume a portable will carry central air conditioning
Leave it uncovered in rain without a rated enclosure

Common rental mistakes

Sizing on the sum of running watts
Add the starting surge of the largest motor, which can be three to seven times its running draw.
Backfeeding the house through a dryer or wall outlet
Use a transfer switch or interlock installed by a licensed electrician.
Renting for a multi-day outage with nobody to refuel
Move up to a diesel unit with a base tank, or arrange fuel service.
Running it in a garage with the door open
Keep it outdoors and well away from every opening into the building.

Carbon monoxide and safe placement

Never run a generator indoors, in a garage, basement, crawl space, tent, trailer or under a covered porch — even with doors and windows open. Exhaust is invisible, odourless and can be fatal within minutes.
Place the unit outdoors on level ground, well away from doors, windows, vents and air intakes, with exhaust directed away from any occupied space. Follow the distance stated in the equipment manual.
Fit a working, battery-backed carbon monoxide alarm in any building or vehicle being powered.
Never plug a generator into a wall outlet or wire it into a building panel. Backfeeding can kill you, your household and utility crews. Any connection to building wiring requires a licensed electrician and a proper transfer device.
Shut the engine down and let it cool before refuelling, and keep fuel away from hot surfaces.

This is educational guidance, not a substitute for the equipment manual, your rental specialist or a licensed professional.

Common questions

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