How To Look At A House

McGarry and Madsen's home inspection blog for buyers of  

site-built, mobile/manufactured and modular homes

What is the average life expectancy of a whole-house standby emergency generator?

Thursday, September 27, 2018

We are going to divide our lifespan estimate into two categories: “rated hours of running time based on regular maintenance” and “years of sitting outside in the weather.” The generator engines of residential emergency generators that use propane or natural gas for fuel are designed for about 3,000 hours of total running time. Allowing for regularly scheduled brief exercise of the units, professional maintenance, and a couple of power outages a year, that translates into about a 30 year life expectancy.

    However, the International Association of Certified Home Inspectors (InterNACHI) rates a standby generator lifespan at 12 years in their Standard Estimated Life Expectancy Chart and, based on our inspection experience, we agree. Our judgement is based on the numerous standby generators installed in 2005, many of which are still sitting—mostly forgotten—in backyards today. 

    Four major hurricanes hit Florida the year before. First Charley, then Frances, Ivan, and Jeanne followed in quick succession between August 13th and September 25th of 2004. A boom in standby generator sales occurred in late 2005, and none of the ones from that era we see today are still functional.

    There are probably a few carefully babied generators out there still able to crank up in a power outage, but we haven’t come across one. Corrosion from Florida’s humid weather speeds up deterioration. Plus, several years of mild hurricane seasons and homeowners tend to forget about backup generator maintenance. The photo above is a 2005 generator that we examined yesterday in Gainesville. The base of the cabinet is beginning to corrode away and it did not respond to testing. 

    And here’s a graph comparing the life expectancy of standby whole-house generators to other electrical components in a home.
    Go to our blog post What is the average lifespan of the parts of a house? for rating of other house components. 

• • • • • • • • • • • • • • • • • • • • • 
Field Guide for Home Inspectors, a quick reference for finding the age of 154 brands of HVAC systems, water heaters, and electrical panels, plus 210 code standards for site-built and manufactured homes, and the life expectancy rating of 195 home components. Available at for $19.95.
• • • • • • • • • • • • • • • • • • • • • • 

Here’s links to a collection some of our other blog posts about “GENERATORS":

What is the best emergency back-up generator for the power outage after a storm? 

Can I run a window air conditioner on a portable generator? 

Why did my generator hookup get tagged as defective by the home inspector? 

How can I determine the age of a Generac standby generator from the serial number?

What size generator do I need to run my submersible well pump?

    Visit our ELECTRICAL and LIFE EXPECTANCY pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

Water Heaters

Water Heater Age

"What Are The

Signs Of..."

Septic Tank Systems

Structure and Rooms

Plumbing Pipes

Termites, Wood Rot

& Pests



When It First

Became Code

"Should I Buy A..."

Park Model Homes


Shingle Roofs




Wind Mitigation

Roof and Attic

"Does A Home


Pool and Spa

"What Is The Difference Between..."




Concrete and

Concrete Block

Metal Roofs


Modular Homes

Rain Gutters

Mold, Lead & Other Contaminants


Older and

Historic Houses

Crawl Spaces

Mobile-Manufactured Homes

Building Permits

Life Expectancy

Clay Soil





Exterior Walls

& Structures


Common Problems

HUD-Code for

Mobile Homes

Garages and Carports

Flat (Low Slope) Roofs

Electrical Panels

Sprinkler Systems

Electrical Receptacle Outlets

4-Point Inspections

Hurricane Resistance

Frequently Asked Questions (FAQ)

Home Inspection

Heating and Air Conditioning

Building Codes

Fireplaces and Chimneys

Inspector Licensing

& Standards

Energy Efficiency

Washers and Dryers



Doors and Windows



Electrical Wiring

Click Below  

for Links

to Collections

of Blog Posts

by Subject

Plumbing Drains

and Traps


Smoke & CO Alarms

Aging in Place

Top 5 results given instantly.

Click on magnifying glass

for all search results.






Air Conditioner & Furnace Age/Size


Electrical Switches





Water Intrusion

Electrical - Old

and Obsolete


Foundation Certifications

Tiny Houses

About McGarry and Madsen



Buying a home in North/Central Florida? Check our price for a  team inspection by two FL-licensed contractors and inspectors. Over 8,500 inspections completed in 20+ years. In a hurry? We will get it done for you.

Moisture Problems

Crawl Spaces