Portable vs. Whole-House Generator: Which Is Right for You?

Power output: 8,000 to 20,000 watts
Price range: $2,000 to $5,000
Fuel needs: 13 to 48 gallons of liquid propane or natural gas per day

Pros: Whole-house generators are largely worry-free. They’re typically sized to power an entire house and they turn on automatically. Propane models can run for days or weeks without refueling, while natural gas models can run indefinitely. They tend to be very quiet, and you don’t need to fuss with weather covers or canopies.

Cons: Whole-house generators are pricier to buy. And the installation costs can range from a few thousand dollars to $10,000 or more. That’s because you might need an electrician to hook the generator up to your electrical panel, plus subcontractors who can handle the plumbing for a gas or propane line and build a steady permanent base for the generator. Models are also reasonably large—about as big as a central air unit—so you need to allocate space for one on the side or back of your house.

Best for: Families who have frequent outages that often last a long time and are willing to pay for the convenience of a nearly seamless transition to a generator that will run almost indefinitely when the power goes out.

Power output: 3,000 to 8,500 watts
Price range: $400 to $1,500
Fuel needs: 12 to 20 gallons of gasoline per day

Pros: Portable generators are much cheaper to buy and install. When a large portable model is connected to your home’s circuit-breaker panel with a transfer switch, it can power almost as much as a home standby generator. Both large and small units have built-in outlets to power appliances with suitable extension cords if you haven’t installed a transfer switch. Smaller inverter units can also be used for camping or tailgating.

Cons: You need to wheel your generator out of storage, connect it to your transfer switch, and fire it up each time there’s an outage. Portable models also require you to store large quantities of gasoline mixed with fuel stabilizer to get through a prolonged outage. They tend to be noisier and have a lower output than home standby models, too. 

Best for: Families on a budget who experience infrequent and relatively short power outages—and are willing to start the generator regularly to make sure it’s ready to go in an emergency.

To reduce the risk of carbon monoxide (CO) poisoning, new generators often feature a built-in sensor that triggers an automatic shutoff if CO builds up to dangerous levels in an enclosed space. Some models also have engines that emit less CO. Recent test data from CR shows that these safety features probably save lives. All portable models in our ratings have one or both of these features. Consumer Reports recommends portable generators only if they pass our CO safety technology test.

But our findings also reveal hazardous gaps that automatic shutoffs fail to address, reinforcing why it’s critical to follow safety guidelines even if your generator is equipped with CO safety features.

• Never operate a generator indoors, including in an open garage, shed, or similar structure.
• Position your portable generator at least 20 feet from your house with the exhaust directed away from it, as well as away from windows, doors, AC units, and other structures.
• Make sure you’ve got a working battery-powered CO detector in your living spaces to warn you of a buildup of the colorless, odorless gas.