Get matched with top generator install pros in Gladbrook, IA

A 1,500 square foot home will likely need a 15kW to 20kW generator. When deciding on whole-house generator size, add up the total wattage of the devices that you’d like to continue running during a power outage. That way, you can ensure you purchase a generator that can power your necessary appliances or medical equipment during an electrical emergency.

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.

No, you should never plug a generator directly into a wall outlet in your house. This practice is extremely dangerous, often illegal, and can cause "back-feeding," where power from the generator flows back into utility lines, creating a life-threatening hazard for utility workers. It can also damage your home's electrical system, including appliances like pumps and HVAC fans. If the main power is restored while the generator is connected, it can destroy the generator and cause an electrical fire. To safely connect a generator, you must use a professionally installed transfer switch or an interlocking kit, which prevents back-feeding by disconnecting your home from the utility grid before the generator provides power.

The amount of time a standby generator can run continuously is around 3,000 hours on average. However, standby generators can generally run indefinitely as long as they have a continuous fuel supply. Generators hooked up to a home’s natural gas supply are the best option for extended usage, as these won’t rely on a finite fuel supply based on how much you have in storage. Generators running on liquid propane or diesel won’t last as long, as these require fuel storage and regular refueling to stay running.