What Size Generac Generator Do I Need?

Choosing the right generator is a question many homeowners ask: what size Generac do I need? At Grounded Electric, we help families prepare for power outages with safe, reliable solutions. Our licensed team, led by Robert “Bobby” Mulholland and co-owner Barret Abramow, ensures every installation matches your home’s power requirements and long-term needs.

How to Determine the Right Generac Size

We offer safe and affordable electrical services for both homes and businesses.

How Do I Determine What Size Generac I Need?

The first step in sizing a generator is to decide what you want to power. Do you want backup power for essentials only, or full coverage for your entire home? Grounded Electric evaluates your needs, from essential appliances to central air and water heaters, to recommend the right generator size.

Running vs. Starting Wattage

Appliances use two types of electricity: running wattage and starting wattage. For example, an air conditioner may require 2,000 watts to run but need up to 4,000 watts to start. Knowing these numbers helps prevent overload. Our electricians calculate both to find the correct standby generator for your home.

Common Appliance Loads

Typical appliances and systems with average running wattage include:

Refrigerator: 700–800 watts
Water heater: 3,000–4,500 watts
Central air system: 2,000–4,000 watts
Sump pump: 1,000–2,000 watts

By adding these values, we estimate the total wattage and select a home standby generator that meets your power requirements.

The 20/20/20 Rule

A useful guideline is the 20/20/20 rule: add 20% to your running wattage, 20% for starting surges, and 20% for future needs. This buffer ensures your generator can handle unexpected demand.

Generator Size Options

Best Whole House Generator Choices

For homeowners who want complete coverage, a whole house generator is the best choice. These house generators keep all systems running, including heating, cooling, and major appliances, during power outages.

10–14 kW for Essentials

A 10–14 kW generator can cover lights, refrigerators, and small appliances. This size is common for smaller households that want basic comfort during outages.

16–22 kW: Is a 22kW Generator Enough?

For medium-sized homes, a 16–22 kW generator is often ideal. A 22 kW unit can power critical systems such as central air, a water heater, and multiple appliances at once, making it one of the most popular options.

26–48 kW for Large Properties

Homes with large square footage or high electrical demand may need a 26–48 kW generator. This range ensures full coverage for heating, cooling, and high-power appliances like pool pumps or EV chargers.

Portable vs. Standby Generators

Portable generators provide temporary relief but require manual setup and fuel management. A home standby generator, installed with a transfer switch, offers automatic power during outages and is the safest long-term choice when you choose a generator for reliability.

Generac Sizing by Home Size

1200 Sq Ft Homes

A 1200 sq ft home may need a 10–14 kW generator, enough to run lights, refrigeration, and basic comfort systems.

1500 Sq Ft Homes

A 1500 sq ft home typically pairs well with a 16 kW generator, which can cover essentials plus an air conditioning unit.

2000 Sq Ft Homes

The common question is what size Generac generator for a 2000 sq ft house? Most require a 20–22 kW generator, capable of powering heating, cooling, and all daily-use appliances.

2500 Sq Ft Homes

Larger 2500 sq ft homes often need 22–26 kW generators. The generator size for your home depends on the total wattage demand and whether you want full or partial coverage.

Technical Sizing Factors

200 Amp Service and Panels

If your home has 200 amp service, you may need a larger standby generator to handle the full load. Choosing the right size ensures your electrical panel is fully supported.

Heating, Cooling, and EV Chargers

Systems like central air, electric heating, or EV chargers add significant demand. These power requirements often push homes toward 22 kW or larger generators.

Transfer Switches, Safety, and Compliance

Every home standby generator must connect to a transfer switch. This device prevents backfeeding and keeps your home compliant with local electrical codes. At Grounded Electric, Barret Abramow oversees compliance checks to protect both safety and property.

Fuel Source and
Consumption

Generators can run on natural gas or propane. Fuel choice affects performance, costs, and runtime during long power outages. Our licensed team evaluates which option fits your household best.

Professional Installation and Support

Site Evaluation and Permits

Proper installation begins with a site evaluation. Bobby Mulholland and his team inspect the property, size the generator, and secure the necessary permits before installation.

Ongoing Maintenance and Service

Generators require regular care, including oil changes and inspections. Grounded Electric provides ongoing maintenance packages to keep your backup generator reliable when you need it most.

Call any time

(201) 385-5000

Contact Grounded Electric

Need help with your electrical panel, generator, or smart home setup? Grounded Electric serves Edgewater NJ and nearby areas with fast, licensed, and dependable service.

For full renovation or remodeling support beyond electrical work, consider working with a trusted General Contractor in Edgewater NJ. A2Z Construction offers full-service project management for kitchens, bathrooms, and home additions.

Call any time

(201) 385-5000