How Much Does a Standby Generator Cost to Install?

Complete Guide to Home Backup Generators

Understanding Generator Costs and Value

Quality home backup generators don't always require a massive investment. Standby generators range from just over $2,000 to $20,000 or more, with installation costs varying significantly based on your specific setup. The key is working with a qualified installer to determine the right size generator for reliable backup power at your home or business.

How Generator Sizing Works

Generators are measured in kilowatts (kW), where one kilowatt equals 1,000 watts of power. A 10kW generator produces 10,000 watts of electricity. A qualified installer will calculate your anticipated electrical loads to determine the proper generator size for your needs.

You have two main options for generator coverage:

Whole House Coverage: Connects to all of your home's electrical circuits Essential Circuits Only: Powers just the most important systems

Common Essential Circuits

Most homeowners prioritize these circuits for backup power:

  • Garage door and gate openers
  • Security systems
  • Refrigerators and freezers
  • Electric ranges and kitchen receptacles
  • Washing machines and clothes dryers
  • Essential lighting circuits
  • Medical equipment, TV, and WiFi receptacles
  • Fan blower motors for gas furnaces
  • Water well and sump pumps
  • Air conditioning systems

While most individual circuits don't require large amounts of power, high-energy appliances like ovens, dryers, and air conditioners significantly impact your total power needs when sizing your system.

The table below provides estimated wattage of various electrical appliances in most homes:

Popular 20kW Generator Solution

The 20kW (20,000 watts) generator represents an excellent balance of power and affordability. These air-cooled units typically cost $5,000-$6,000, making them budget-friendly compared to liquid-cooled alternatives. The popular Cummins RS20A Kit, which includes a 200-Amp Automatic Transfer Switch, costs just over $6,000.

Cummins QuietConnect RS20AC 20kW Kit with 200A Automatic Transfer Switch

Understanding Transfer Switches

The Automatic Transfer Switch (ATS) serves as the brain of your backup power system. It continuously monitors utility power and automatically switches to generator power during outages. Crucially, it prevents electrical currents from flowing backward into utility lines, ensuring safe operation.

Cummins RA Series Transfer Switch

Types of Transfer Switches

Manual Switches: Used with portable generators, requiring manual operation Automatic Transfer Switches: Used with standby generators for seamless operation

Sizing Your Transfer Switch

Your ATS must match your electrical panel's capacity. If your home has a 200-amp main breaker panel, you need a 200-amp ATS. For a 100-amp panel, you need a 100-amp switch.

Multiple Panels: If your home has multiple electrical panels and you want whole-house coverage, you'll need an ATS for each main breaker panel. For essential-circuits-only coverage, your installer can consolidate essential circuits into one panel, requiring only one ATS.

Important Note: Sub-panels differ from main breaker panels in that they receive power from the main panel rather than serving as the primary electrical distribution point. When a transfer switch is installed at the main breaker panel that includes a dedicated breaker for the sub-panel, the generator will supply power to both the main panel and any connected sub-panels through this configuration. Alternatively, a non-service rated transfer switch can be connected to a sub-panel if you wish to only power circuits found on the sub-panel.

Service Entrance vs. Non-Service Rated Switches

Service Entrance Rated: Required for main breaker panels (typically 200 amps) 
Non-Service Rated: Used for sub-panels without main breakers

Installation Configurations

Whole House Generator Installation

This setup connects your generator to all house circuits, providing complete coverage but at higher cost.

Partial House Generator Installation

A cost-effective approach that powers only essential circuits. Here's how it works:

Example Scenario: You have a two-story home with gas heat and hot water. Your essential circuits include kitchen appliances, heating system blower, security system, garage door, downstairs lighting and receptacles, and one air conditioning unit.

Your installer will relocate all essential circuits to one main breaker panel (your "generator panel"), while non-essential loads like upstairs circuits and laundry equipment go to the other panel. This requires only one appropriately sized ATS.

Load Management: Cummins air-cooled generators include built-in load management, allowing one air conditioner to operate at a time. When one cycles off, power becomes available for the other, with priority settings available.

Project Costs and Budgeting

Equipment Costs

  • 20kW generators with ATS: Starting around $6,200
  • Cummins RS20A: Popular choice for quiet, reliable operation

Installation Costs

Installation costs vary significantly based on generator placement relative to gas and electrical meters. The most economical installations position the generator near both meters on the same side of the house.

Rule of Thumb: Expect installation costs to approximate equipment costs. A $6,200 generator and switch typically results in a $12,500 or more total project cost. Generators positioned away from utility connections will cost more to install.

Liquid-Cooled Generators: Project costs begin in the mid-teens and often exceed $20,000.

Choosing the Right Generator for Your Home

Cummins RS20A Applications

Whole House Solution: Ideal for most homes under 2,000 square feet with gas heat and hot water

Managed Whole House: Works for most homes up to 3,000 square feet with load management

Essential Circuits: Perfect for larger homes focusing on critical systems

When You Need Liquid-Cooled Generators

Homes exceeding 3,000 square feet or all-electric homes requiring whole-house coverage typically need liquid-cooled generators for adequate power.

Avoiding Common Mistakes

Don't fall for misleading "Whole House Generator" labels at big box stores. The term "whole house" refers to the transfer switch capacity, not the generator's actual power output. A 200-amp ATS provides "whole house coverage" by connecting to your home's 200-amp service, but the generator must have sufficient capacity to handle your actual electrical loads.

Critical Success Factor: Always calculate your anticipated electrical loads before purchasing equipment. Better yet, consult with an experienced, authorized dealer who can properly size your system.

Professional Consultation

The best investment you can make is consulting with an industry professional before making any purchases. Many homeowners make costly mistakes by buying generators without understanding their actual power requirements.

Work with an experienced installer who is also an authorized dealer for the manufacturer. This ensures proper sizing, installation, and ongoing support for your backup power investment.

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For professional generator consultation and installation, contact Buckeye Power Systems, a Certified Cummins Dealer offering quiet, high-performance generators for reliable residential and business backup power. We ship generators throughout the U.S. lower 48. Call 901-379-8097 for sizing assistance and questions.