Choosing a Power Generator for Your Home

A power generator can be a lifesaver when the electricity goes out. 

They’re available in a wide range of types and sizes, from portable models that require manual starting and hook up to whole house standby generators which turn on automatically when the power goes out.

Read on to learn more about each type and see which option is best for your home.

In This Article:

Portable Power Generators

• Inverter and Conventional Portable Generators
• How to Set Up a Portable Generator
• Portable Generator Safety
• Portable Generator Maintenance Tips

Automatic Standby Generators

• How an Automatic Standby Generator Works
• How to Choose The Size
• Standby Generator Maintenance Tips

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Portable Power Generators

A portable generator can power a few lights and an appliance, like a fridge, as long as it doesn’t use a lot of electricity.

Portable generators also offer many advantages in remote outdoor situations. They can power everything from tools to lights to music.

With a portable generator, you have to move it outside, find the gas can and extension cords, fill the gas tank, run the cords through the house, manually start the generator, and refuel it every few hours.

There are some important differences between portable generators designed for residential and commercial use. Residential generators usually provide emergency backup power for select appliances within a home and provide from 1,000 to 8,000 watts of power

Portable generators for commercial use are often used on a jobsite to run power tools when electricity isn’t available. These units tend to receive more use and generate between 3,000 and 17,500 watts of power.

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Inverter and Conventional Portable Generators

Portable generators are either conventional or inverter. Conventional generators use a mechanical alternator to produce AC power while inverter generators produce DC power and convert it to AC power using digital electronics. Inverter generators are smaller and lighter but more expensive.

Conventional generators run at a constant 3600 RPMs while inverter generators can run at variable speeds depending on the electrical demand. This allows inverter generators to run at slower speeds much of the time, which saves fuel and reduces noise.

Inverter generators usually produce cleaner power with a total harmonic distortion of less than 5 percent while conventional are capable of greater output and extended run times.

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How to Set Up a Portable Generator

To set up a portable generator, first, attach the wheels and handles. Then, fill the crankcase with the correct grade of oil and the fuel tank with the proper fuel.

If you plan to use a portable generator to back up your home or business, use it in conjunction with a manual transfer system, which consists of a manual transfer switch, power inlet box and power cord.

The manual transfer switch is connected to the main electrical panel, so only the circuits to be powered by the generator are active during an outage.

The power inlet box is mounted outside the home or business. It is hardwired to the manual transfer switch and connected to the generator by a power cord.

When the lights go out, first shut off the power from the utility at the manual transfer switch, then start the generator to energize the selected circuits wired to it. This will prevent your generator from backfeeding power into utility lines and possibly injuring repair crews.

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Portable Generator Safety

Take stock of your generator. Make sure the equipment is in good working order before you start using it.

Follow all instructions. Review the owner’s manuals for your equipment if possible (you can look manuals up online if you cannot find them) so you can operate your equipment safely.

Ensure proper ventilation. Carbon monoxide, an invisible, odorless gas from gasoline-powered generators, is deadly, so never run a generator indoors or even in a partially enclosed space like a garage. Only operate them outdoors away from windows, doors, crawl spaces, and vents. Install a battery-operated carbon monoxide detector in your home or business to alert you to any carbon monoxide that comes into the building.

Have the right fuel on hand. Use the type of fuel recommended by the manufacturer. It is illegal to use any fuel with more than 10 percent ethanol in outdoor power equipment (for more information on proper fueling for outdoor power equipment visit www.LookBeforeYouPump.com). If you are using fuel that has been sitting in a gas can for more than 30 days and you cannot get fresh fuel, add a fuel stabilizer to it. Store gas only in an approved container and away from heat sources.

Only add fuel to a cool generator. Never refuel a generator when it’s running or still hot, since spilled fuel could cause a fire or explosion. When you do fill the tank, leave room for the fuel to expand.

Watch: Safety Tips For Operating a Generator 

Keep the generator dry. You can buy model-specific tents online or generator covers at home centers and hardware stores. Choose a flat, level spot with several feet of clearance on all sides and properly ground the unit to avoid the risk of electrocution.

Install a transfer switch. A transfer switch connects the generator to your circuit panel and lets you power hardwired appliances. Most transfer switches also help you avoid overload by displaying wattage usage levels.

Watch: Tips to Keep a Portable Generator Working Its Best

Plug in safely. If you don’t yet have a transfer switch, you can use the outlets on the generator. It’s best to plug in appliances directly to the generator. If you must use an extension cord, it should be designed for outdoor use. It should be rated (in watts or amps) at least equal to the sum of the connected appliance loads. Make sure the cord is free of cuts and all plugs should have all three prongs. 

Don’t overload. The combined wattage of all the devices plugged into the generator should never exceed the rated capacity of either the generator or extension cord. Prioritize your needs to make sure the equipment you operate doesn’t exceed the generator’s output rating.

Do not use the generator to “backfeed” power into your home electrical system. Trying to power your home’s electrical wiring by “backfeeding” – where you plug the generator into a wall outlet – is reckless and dangerous. You could hurt utility workers and neighbors served by the same transformer. Backfeeding bypasses built-in circuit protection devices, so you could damage your electronics or start an electrical fire.

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Portable Generator Maintenance Tips

• Store it in a location where the equipment won’t be exposed to excessive dust, dirt, moisture, or corrosive vapors.
• Clean it occasionally with a damp cloth or soft bristle brush.
• Don’t hose the it down with water.
• When storing the unit for more than 30 days, you should empty the fuel or add a fuel stabilizer to the tank and run it through the system.
• If the generator has an electric start, keep the battery charged during long storage.
• Run the it for 10 minutes or so every 2 to 3 months.

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Automatic Standby Generators

To power heavy loads and the circuits in your home, you will need a standby generator, also called a whole house generator. 

When the power to your home fails, a standby generator goes to work automatically. It then shuts itself off when the utility power resumes. 

Watch: Why You Should Choose a Generac Standby Generator

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How an Automatic Standby Generator Works

An automatic standby generator system monitors incoming voltage from the utility line. When the utility power is interrupted, it automatically goes to work.

The automatic transfer switch safely disconnects the utility line and simultaneously connects a new power line, providing emergency power within seconds. When the utility power is restored, the generator automatically returns to standby mode.

Because these systems are fueled by your home’s natural gas or propane supply, you don’t even have to worry about pouring gasoline.

So unlike a portable generator, you don’t have to refuel it. Once a week, it automatically runs a brief self-test to ensure that everything is working properly when you need it.

Depending on which model you choose, whole house generators can provide different levels of power, including:

• Essential Circuit Coverage: Provides power only to important basic circuits such as heat, lights, and refrigerators.
• Managed Whole House System: Automatically switches to manage the load to power other circuits and appliances as available.

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How to Choose The Size 

The size of your home doesn’t determine the size of a standby generator.

You need one sized appropriately for the appliances you want to backup. There are a few things you can do to determine how much backup power you really need, regardless of how big or small your home is.

One approach is to identify the power consumption of all of the lights and appliances you want to backup. These could be only critical items, like your furnace and sump pump; a few rooms, such as your living room and kitchen; or your whole house.

In any case, write down how many watts each appliance uses as you conduct your survey. You usually can find this information affixed to the appliance in a discreet location. If you cannot find this data on the appliance itself, consult the owner’s manual.

Appliances with motors — like your furnace, AC and fridge — require a small boost of power to start those motors. This boost is called “surge watts.” To account for it, multiply the appliance’s rated running watts by 1.5, and write that number down instead.

When finished, add it all up. That total is how much power you will require (at most) in an emergency, and will guide you in selecting the size you need.

For a more detailed, high-tech course of action, consider buying a home energy monitor. There are several to choose from depending upon your budget. They’re easily installed, and will give you a real-time view into your power consumption. Use one for at least 30 days to see how much power you consume every day on average.

Many energy monitors allow you to examine individual loads. This can give you insight into how your high-demand appliances affect your overall energy consumption. By analyzing your common loads and your high-demand loads separately, you will be able to size your generator to effectively manage both of them.

Be sure to account for loads that you only use seasonally. For example, if you use the energy monitor in the winter, make sure to account separately for the power consumption of your air conditioner, or other appliances you only use during the summer.

With continued use, a power monitor will also help you find ways to adjust your energy consumption so you can save money on your utility bills.

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Standby Generator Maintenance Tips

• A standby generator should run a brief self-test once a week to ensure that everything is working properly. Verify that the unit ran and has no alarms or warnings.
• Ensure the it is in “auto” mode, so it will automatically start up.
• Make sure the unit is clean and free of debris, inside and outside the enclosure.
• Keep the battery terminals clean and tight.
• Have your unit serviced every six months by an authorized service dealer.

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Further Reading

• How to Prepare for a Hurricane
• Winter Survival Kit: 25 Items to Stock in Your Car
• Power Outages: How to Prepare Before Severe Weather