When maintained properly, a whole-house generator can last up to 20 years. Costs to maintain and repair generators vary by location and type of generator, but you can expect to pay about $150 to $300 per year for annual generator maintenance checks. An experienced generator service technician will inspect your generator’s engine filter, starting mechanism, fuel, lubrication, and coolant levels to keep your generator in good working condition for as long as possible.

Installing a whole-house generator costs about $5,000 on average. Prices range from $1,550 to $8,500, depending on size, brand, fuel type, and assembly. The size of your whole-house generator is the most significant cost factor, with large homes with high energy demands costing the most to power. Types of whole-home generators include:

• Portable generators with 1kW–7.5kW capacity: $500–$2,000

• Partial generators with 9kW–20kW capacity: $2,000–$6,300

• Whole-house generators with 22kW–48kW: $5,000–$18,000

When choosing the right size generator for your needs, consider a few items to help calculate the wattage you’ll need. Start by determining which household items and appliances you want to power, and then add the wattages together. Check out the wattage of these essential appliances:

• Refrigerator: 600 watts

• Large dehumidifier: 700 watts

• Large window air conditioner: 1,400 watts

• Water heater: 3,000 watts

Running home appliances like these requires a partial or whole-house generator. A portable generator may be enough to power your home if you only plan to keep a refrigerator and freezer running. 

Here’s what you can run with different wattages and types of generators:

Portable generator:

• 2,000 watts can handle a large appliance like a freezer or refrigerator, plus a few smaller items like phones or computer chargers. 

• 4,000 watts will keep two large appliances operating and a few smaller devices.

• 8,000 watts should power most essential appliances and other devices, including a sump pump, well pump, or your dishwasher.

Partial to whole-house generator:

• 20,000 watts and above will make it seem like your home’s power is still on.

The value of installing a whole-house generator is that your home has guaranteed power, even if the power grid in your area is down. Whether a whole-house generator is worth installing in your home depends on how often you use it, your home’s location, and your lifestyle. For example, installing a whole-house generator is likely worth it if you:

• Experience frequent or prolonged power outages

• Work from home

• Store a lot of cold food

• Have a sump pump

• Have a pump for well water

• Use electronic medical devices

• Live in a climate requiring heating or cooling