You've decided that a whole house generator is the right investment for your family. Smart move—especially here in the Greater Binghamton area, where winter storms, summer thunderstorms, and aging infrastructure can leave you without power when you least expect it. But now comes the question that trips up most homeowners: what size generator do you actually need?

It's a more important question than many people realize. Buy a generator that's too small, and you'll be forced to choose which appliances to power during an outage. Buy one that's too large, and you've spent more money than necessary on equipment that will never run at its potential. At Albrite Electric, we've been helping Greater Binghamton homeowners find the perfect generator fit since 1999. Let's break down everything you need to know about sizing your whole house generator correctly.

Understanding Generator Power Ratings

Before we dive into sizing, it helps to understand how generator power is measured. Generators are rated in kilowatts (kW), which indicates how much electrical power they can produce. You'll typically see two ratings for any generator: running watts and starting watts.

Running watts (also called rated watts) represent the continuous power a generator can supply. This is the steady power needed to keep your appliances running once they're already on.

Starting watts (also called surge watts) represent the extra power needed to start motor-driven appliances. When your air conditioner compressor kicks on or your well pump starts, it requires a brief surge of power that can be two to three times its running wattage. Your generator needs enough capacity to handle these surges.

For example, your central air conditioner might need 3,800 running watts to operate, but require 4,950 starting watts to turn on. A properly sized generator accounts for both these needs.

What Appliances Do You Want to Power?

The first step in sizing your generator is determining exactly what you want to keep running during a power outage. Most homeowners have three options:

Essential Circuits Only: This approach covers the basics—refrigerator, some lights, a few outlets, and perhaps your furnace fan. A smaller generator in the 7.5 to 10 kW range can typically handle essential circuits. This is the most economical option but means making choices about what stays on during an outage.

Managed Whole House: With a managed whole house system, smart technology prioritizes power delivery to your most important circuits while cycling less critical loads on and off as needed. This lets you get whole house coverage with a mid-sized generator (typically 18-22 kW) by intelligently managing demand.

Full Whole House: For complete peace of mind, a larger generator (22-26 kW or more) can power everything in your home simultaneously, just as if utility power had never gone out. This is ideal for larger homes or households with significant electrical demands.

Calculating Your Home's Power Requirements

To get a rough idea of your power needs, you'll need to add up the wattage requirements of everything you want to run. Here are some common household items and their typical power requirements:

Heating and Cooling:

• Central air conditioner (3-ton): 3,800 running watts / 4,950 starting watts
• Furnace fan blower (½ HP): 800 running watts / 2,350 starting watts
• Space heater: 1,800 running watts
• Window AC (10,000 BTU): 1,200 running watts / 1,800 starting watts

Kitchen Appliances:

• Refrigerator/freezer: 700 running watts / 2,200 starting watts
• Microwave (1000W): 1,000 running watts
• Electric stove (one 8" element): 2,100 running watts
• Dishwasher: 1,500 running watts / 1,500 starting watts

Essential Systems:

• Sump pump (½ HP): 1,050 running watts / 2,200 starting watts
• Well pump (⅓ HP): 1,000 running watts / 2,200 starting watts
• Electric water heater: 4,000 running watts
• Security system: 500 running watts

Other Common Items:

• LED TV (55"): 90 running watts
• Laptop computer: 85 running watts
• WiFi router/modem: 20 running watts
• Washing machine: 1,150 running watts / 2,250 starting watts
• Electric dryer: 5,400 running watts / 1,350 starting watts
• Garage door opener: 875 running watts / 2,350 starting watts

Add up the running watts for everything you want to power, then add the highest starting wattage from the list. This gives you a baseline for your generator size. For instance, if your running watts total 15,000 and your largest starting surge is 4,950 watts, you'd need at least a 20 kW generator.

Factors That Affect Generator Sizing in the Binghamton Area

Beyond basic wattage calculations, several local factors influence what size generator is right for your home:

Heating System Type: In our cold Binghamton winters, heating is a major consideration. Natural gas furnaces only need power for the blower fan, making them relatively easy to run on generator power. Electric heat pumps and electric furnaces, however, have much higher power demands. If you rely on electric heat, you'll need a significantly larger generator to stay comfortable during winter outages.

Well Water: Many homes in Vestal, Owego, and other areas outside the municipal water system rely on well pumps. These pumps have significant starting surge requirements that must be factored into your generator sizing.

Home Size and Electrical Panel Capacity: Larger homes typically have higher electrical demands. Your electrical panel capacity (100, 200, or 400 amps) also provides clues about your home's overall electrical infrastructure and needs.

Electric Vehicles: If you have an EV charging station and want to charge your vehicle during an extended outage, you'll need to account for that significant load in your generator sizing.

Home-Based Business or Medical Equipment: If you work from home or have family members who depend on powered medical equipment, reliable whole house power isn't just convenient—it's essential. These situations often warrant a larger generator for complete peace of mind.

Common Generator Sizes and What They Can Power

Generac, the brand we install and service at Albrite Electric, offers a range of generator sizes to meet different needs:

7.5 kW (PowerPact Series): An economical choice for essential circuit coverage. Powers your refrigerator, some lights, sump pump, and furnace fan. Ideal for smaller homes or budget-conscious homeowners who want basic protection.

18 kW (Guardian Series with Smart Management): A popular mid-range option that uses smart load management to provide whole house coverage. The system automatically prioritizes power delivery, so your most important circuits always stay on while managing demand across your home.

22-24 kW (Guardian Series): Sufficient for most homes to power everything simultaneously without load management. A solid choice for typical Binghamton-area homes with central air conditioning and standard electrical demands.

26 kW (Guardian Series): Generac's most powerful air-cooled generator, designed for larger homes with higher electrical demands. Offers 28% more motor starting power than comparable units, ensuring even large AC compressors and well pumps start reliably.

Why Professional Sizing Matters

While online calculators and general guidelines can give you a rough idea of your needs, there's no substitute for a professional assessment. Here's why:

Accurate Load Calculations: A qualified technician will evaluate your actual electrical panel, identify your specific appliances and their power requirements, and calculate your true load—not just estimates based on averages.

Electrical Infrastructure Assessment: Your home's wiring, panel capacity, and existing circuit breakers all factor into generator installation. A professional can identify any electrical upgrades that might be needed.

Installation Considerations: The location for your generator, distance from your electrical panel, fuel source availability (natural gas vs. propane), and local code requirements all influence the right system for your home.

Future Planning: Are you considering adding central air? Planning a home addition? A professional can help you choose a generator that meets not just your current needs but your anticipated future needs as well.

The Cost of Getting It Wrong

Undersizing your generator means frustration during outages—having to choose between air conditioning and cooking, or between the well pump and the dryer. You might find yourself manually cycling appliances on and off, defeating the purpose of automatic backup power.

Oversizing wastes money on equipment you don't need and may actually reduce efficiency. Generators run most efficiently when operating at a reasonable percentage of their capacity. A significantly oversized generator running at minimal load can experience problems like wet stacking and shortened engine life.

The sweet spot is a generator that handles your actual needs with some room for the occasional high-demand situation—not too small to be useful, not so large that you've overpaid for capacity you'll never use.

Get Your Free Generator Assessment

At Albrite Electric, we take the guesswork out of generator sizing. Our free in-home assessment includes a thorough evaluation of your electrical system, discussion of your backup power priorities, and a detailed recommendation tailored to your home and budget.

We've been the trusted whole house generator installer for families throughout Binghamton, Endwell, Johnson City, Endicott, and the entire Southern Tier since 1999. Our factory-trained technicians know Generac generators inside and out, and we stand behind every installation we perform.

Ready to find out what size generator is right for your home? Call Albrite Electric today at (607) 748-2105 or request your free estimate online. We'll help you find the perfect balance of power, reliability, and value for your Greater Binghamton home.