Get matched with top generator install pros in Lynnfield, MA

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.

With proper maintenance, a whole-house generator can last between 20 and 40 years. The specific lifespan depends on how often and for how long the generator is used, and some models may have their life expectancy rated in hours of operation. To maximize its lifespan, expect to spend around $150 to $300 per year for annual maintenance checks from a qualified technician. During these checks, a technician will inspect the engine filter, starting mechanism, fuel, lubrication, and coolant levels. Consulting your installer and choosing a low-impact fuel like natural gas or diesel can also help ensure your generator lasts as long as possible.

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.

Homeowners can often access federal tax credits, such as the Investment Tax Credit (ITC), which covers a percentage of installation costs. Many states and utilities offer additional rebates, grants, or performance-based incentives. These programs can significantly lower your upfront investment. Check the Database of State Incentives for Renewables and Efficiency (DSIRE) or contact your local energy office for current offers.