​Essential Guide to Home Standby Generators

​A home standby generator is a permanently installed backup power system that provides a reliable safety net during grid failures.

Unlike portable units, standby generators are integrated into your home's electrical and fuel systems, allowing for automatic operation without manual setup during a storm. 


How They Function

The core of a standby system consists of three main parts: the generator unit, an automatic transfer switch (ATS), and a permanent fuel source. 

1. Detection: The ATS constantly monitors the utility power. When it detects a loss of voltage, it signals the generator to start, typically within seconds.
2. Conversion: The generator’s engine (powered by gas or propane) turns an alternator, converting mechanical energy into electrical power through electromagnetic induction.
3. Transfer: Once the generator reaches the correct speed, the ATS disconnects the home from the utility grid and connects it to the generator. This prevents "backfeeding," a dangerous situation where power flows back into utility lines.
4. Recovery: When grid power returns, the ATS confirms stability, switches the home back to utility power, and shuts down the generator after a brief cool-down period. 

System Choices and Sizing

Choosing the right system depends on your fuel availability and power requirements.

• Fuel Options: Most residential units run on natural gas (for an unlimited supply) or liquid propane (stored in an on-site tank). Diesel is also an option but is more common in commercial settings.
• Sizing (Wattage): Units range from small 7.5 kW models to large 26 kW+ whole-house systems.
  • Essential Circuit Coverage: Powers only critical loads like the refrigerator, furnace, and a few lights.
  • Managed Whole-House: Uses "load shedding" technology to prioritize large appliances (like AC units) so they don't all run simultaneously, allowing a mid-sized generator to power a large home.
  • True Whole-House: A larger unit (typically 20 kW+) designed to run all household loads at once. 

Strategic Placement

Placement is governed by strict safety codes, such as NFPA 37, to prevent fire and carbon monoxide (CO) poisoning. 

• Distance from Openings: Units must typically be at least 5 feet away from windows, doors, and vents to prevent exhaust fumes from entering the home.
• Wall Clearance: While general rules suggest 18–36 inches from the house, some fire-tested models can be placed closer if the wall is non-combustible.
• Airflow and Access: Maintain 3 feet of clearance on the front and sides for maintenance access and at least 5 feet of overhead clearance. Never install a generator under a deck or in an enclosed space. 

Maintenance Essentials

To ensure the generator starts when needed, it requires regular upkeep similar to a car engine. 

• Self-Exercise: Most modern units are programmed to run for about 10–20 minutes weekly or bi-weekly to circulate oil and test systems.
• Routine Checks:
  • Monthly: Check oil levels and inspect the enclosure for debris or pests.
  • Annual/Bi-Annual: Change the oil, oil filter, air filter, and spark plugs.
  • Battery Care: Inspect and clean battery terminals annually; batteries typically need replacement every 3–5 years.
• Break-In Period: New units often require their first oil change after only 20–25 hours of initial runtime. 

A well-maintained standby generator can last 20 to 30 years, providing long-term security for your property and family.

Learn more about standby generators