Whole-house generators need to be installed on level ground several feet away from walls and other objects. Because they tap into the electrical system directly, they usually need to be close to your home electrical panel for a transfer switch installation. It also helps with installation if they are near to a gas line or propane tank installation.

To determine the right size generator for your house, you should calculate the total wattage of the appliances and devices you want to power during an outage. List all essential items, note their start-up wattages, and add them together.

Here are some typical wattage requirements for common appliances:

• Refrigerator: 600 watts

• Large dehumidifier: 700 watts

• Large window air conditioner: 1,400 watts

• Water heater: 3,000 to 4,500 watts

• Electric furnace: 5,000 to 25,000 watts

A 7,500-watt generator might be sufficient for essentials like a refrigerator, freezer, well pump, and lighting circuits. However, for high-demand items like a water heater or furnace, a whole-home generator is a better choice. A portable generator may be enough if you only need to power a few critical items.

While home square footage can offer a rough estimate, it is not always a reliable indicator. For reference, here are some typical generator sizes based on square footage:

• 1,000 sq ft: 6–9 kW

• 1,500 sq ft: 7–10 kW

• 2,000 sq ft: 10–14 kW

• 2,500 sq ft: 12–16 kW

• 3,000 sq ft: 16–20 kW+

For the most accurate sizing, consult a professional who can calculate your home's peak and average power consumption and recommend the optimal generator.

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.

While natural gas generators are costly, they’re a great option for standby power due to the reliability of natural gas as a fuel source. Unlike other fuels, natural gas is delivered through underground pipes, making outages extremely rare and less likely to be affected by the elements. As long as the area isn’t prone to earthquakes, they offer an unlimited supply of natural gas that doesn’t degrade over time or require storage in tanks.