Simple Guide for Selecting a Home Generator

When power outages strike, a home generator can keep your essential appliances and systems running smoothly. In the video above, Ask This Old House master electrician Heath Eastman teaches host Kevin O’Connor what to consider when selecting a generator. His advice will help you make an informed choice based on your specific needs.

Assessing Your Generator Needs

Before investing in a generator, we recommend evaluating your specific requirements. Your decision will hinge on several key considerations.

Frequency of Power Outages

How often does your area experience power outages? If blackouts are rare, a generator might be unnecessary. However, if you live in a region prone to severe weather—think frequent ice storms, hurricanes, or recurring power disruptions—a generator could be a valuable investment that saves you from inconvenience and potential safety hazards.

Power Requirements

Determine which appliances and systems you need to keep running during an outage. This evaluation should include all the necessities that contribute to the safety and comfort of your home environment. Some items to consider include:

• Heating and cooling systems: Critical in areas with extreme temperatures.
• Refrigerator and freezer: To prevent food from spoiling.
• Well pump: If your water supply depends on it.
• Medical equipment: Vital for households with health-related needs.
• Lighting: For safety and security.
• Communication devices: To stay connected during emergencies.

Understanding your power needs will help you choose a generator that can handle the required load without unnecessary expense.

Comfort Level

Next, decide how much power you need to stay comfortable during an outage. Some homeowners are content with the basics, while others want more coverage to maintain their everyday lifestyle. Whether you prioritize keeping the household running as usual or are okay with just powering must-have items, this step will help guide your choice between a smaller, portable generator and a larger, automatic standby system.

Types of Home Generators

Home generators generally fall into two categories: portable generators and automatic standby generators. Each type offers distinct benefits and drawbacks.

Portable Generators

Portable generators are versatile and affordable, typically costing between $500 and $2,000*. These units offer a few advantages:

• Lower initial cost: They’re more accessible to homeowners.
• Flexibility: You can move them to different locations as needed.
• Useful for critical systems: They can power essential appliances and systems during an emergency.

However, portable generators have some limitations that are worth noting:

• Manual setup: You’ll need to set it up during each outage, which can be inconvenient in an emergency.
• Limited power output: They’re typically unable to power an entire home.
• Fuel storage and refueling: They require gasoline, which you’ll have to store and refill during prolonged outages.
• Safety concerns: You must use them correctly to avoid carbon monoxide poisoning.

Automatic Standby Generators

Automatic standby generators provide a more comprehensive solution for home backup power:

• Automatic start: The generator starts automatically when grid power fails.
• Seamless power: They provide a smooth transfer of power to keep your home running.
• Whole-house coverage: They can power most or all of your home’s electrical needs.
• Reliable fuel source: These units typically run on natural gas or propane, so there’s no need for manual refueling.

The downside is their higher cost; they can run $2,000–$30,000 for the generator and transfer switch.

*Cost information in this article is based on 2024 data from Angi.

Fuel Sources for Generators

The type of fuel your generator uses will impact its performance, availability, and maintenance. Here are the most common fuel sources:

Gasoline

Gasoline is the most common for portable generators and is widely available at gas stations. It’s readily accessible, but it requires proper storage and rotation to avoid degradation. While gasoline is potent, it has a shorter shelf life than other fuel types.

Propane

Propane is cleaner burning than gasoline, reducing its environmental impact. It also has a longer shelf life for greater flexibility in fuel storage.

Propane has a lower power output than gasoline and may require a larger tank for extended outages.

Natural Gas

Natural gas is the most common for automatic standby generators because of its continuous supply through utility lines. It requires no refueling or storage, so it’s very convenient. Natural gas offers a reliable and constant power source without manual fuel management.

Each fuel type has pros and cons, so selecting the right one depends on availability, ease of use, and specific power needs.

Sizing Your Generator

Choosing the right size generator is important for efficiently meeting your power needs. An undersized generator won’t handle your load, while an oversized one can waste money and fuel.

Electrical Load Calculation

Calculate the total wattage of all appliances and systems you want to power simultaneously. This includes everything from your refrigerator to your heating system. Add the wattage ratings from appliance labels or manuals to determine your minimum generator size.

Starting vs. Running Wattage

Remember that some appliances, like refrigerators and air conditioners, require more power to start than to run continuously. These starting wattages can sometimes be two to three times higher than their running wattages. Be sure to verify that your generator has enough capacity to handle these surges in power demand.

Future Needs

When sizing your generator, factor in potential future electrical needs. If you plan to add significant appliances or expand your living space, add these to your generator size calculations.

Generator Installation and Safety Considerations

Proper installation and safe operation are key to getting the most from your generator while avoiding hazards.

Professional Installation

A certified professional should always install automatic standby generators. Certified technicians can
safely connect the generator to your home’s electrical system and fuel source while adhering to local safety codes and regulations.

Portable Generator Safety

When using a portable generator, follow these safety best practices:

• Operate it outdoors in a well-ventilated area to prevent carbon monoxide buildup.
• Keep it away from windows and doors to avoid exhaust entering your home.
• Use proper extension cords rated for outdoor use to connect appliances.
• Never operate in wet conditions to prevent electric shock.

Carbon Monoxide Awareness

All fuel-burning generators produce carbon monoxide, a deadly gas. Install carbon monoxide detectors in your home to alert you of any dangerous buildup. Always follow manufacturer guidelines to operate your generator safely.

Generator Maintenance Requirements

Regular maintenance is important for keeping your generator in working order and ready for use when needed.

Follow these tips for portable generators:

• Run the generator monthly to verify it starts and runs smoothly.
• Change oil and filters as recommended by the manufacturer to prolong engine life.
• Store with stabilized fuel or an empty fuel tank to prevent fuel system issues.

If you have an automatic standby generator, here’s what to do:

• Schedule annual professional maintenance to keep the system in optimal condition.
• Perform monthly self-tests and visual inspections.
• Keep the area around the generator clear of debris to provide proper ventilation.

Alternative Power Backup Solutions

While traditional generators are popular, there are alternative options for power backup:

Solar Power With Battery Storage

As solar technology advances, more homeowners are turning to solar power systems with battery storage. These systems provide clean, renewable energy with no emissions. They operate silently, unlike traditional generators, and require minimal maintenance.

However, the upfront cost is higher—between $2,000 and $25,000—and solar systems may not provide as much power during extended outages, especially during cloudy periods.

Inverter Generators

Inverter generators are a quieter, more fuel-efficient alternative to traditional portable generators. They run more quietly, making them ideal for residential areas. They also produce cleaner power, which is safer for sensitive electronics, and they’re more fuel-efficient.