Standby Generator Maintenance: Complete Schedule and Checklist
A standby generator is a mechanical system with an engine, and like any engine, it requires regular maintenance to operate reliably when you need it most. The good news is that standby generator maintenance is straightforward, predictable, and inexpensive relative to the value the generator provides. Here is the complete maintenance schedule for residential standby generators from Generac, Kohler, Cummins, and Briggs and Stratton.
Weekly: Automatic Exercise Cycle
Every modern standby generator runs a self-test (exercise cycle) once per week at a time you program during installation. During this 10 to 15 minute run, the engine starts, reaches operating temperature, runs under no load or light load, and shuts down. The exercise cycle keeps engine oil circulated, keeps internal components lubricated, charges the starter battery, and verifies that the automatic start system functions properly. This is automatic and requires no intervention from the homeowner. Check your generator controller display periodically to verify the exercise cycle is running as scheduled.
Every 6 Months: Visual Inspection
Twice per year, perform a visual walkaround of your generator. Check the enclosure for damage, rust, or paint deterioration. Clear any debris (leaves, grass clippings, dirt) from the intake and exhaust vents. Verify that no plants, mulch, or landscaping materials are encroaching on the required clearance zones around the unit (typically 18 to 36 inches on all sides, 60 inches from the exhaust). Inspect the air filter and clean or replace if dirty. Check the battery terminals for corrosion and clean if needed. Verify the fuel connections (gas line or propane line) show no signs of leaks or deterioration.
Annually: Oil and Filter Change
Change the engine oil and oil filter once per year or every 200 hours of operation, whichever comes first. Most residential generators experience far fewer than 200 hours of runtime per year (the weekly exercise cycle adds approximately 10 to 13 hours annually), so annual oil changes are the standard schedule. Use the oil type and viscosity specified in your generator manual. For Generac Guardian models, synthetic 5W-30 is the standard recommendation. Kohler and Cummins specify their own approved oil types. Generac, Kohler, and Cummins all offer maintenance kits that include the correct oil filter, air filter, and spark plugs for your specific model. IB Lighting carries these kits in our online shop.
Every 2 Years: Spark Plugs
Replace spark plugs every 400 hours of operation or every 2 years, whichever comes first. Spark plugs are inexpensive ($5 to $15 each) and accessible on most residential generator models. Fresh spark plugs ensure reliable starting and clean combustion. Worn spark plugs can cause hard starting, misfiring, and increased fuel consumption.
Every 3 to 5 Years: Battery Replacement
The starter battery powers the automatic start sequence when the transfer switch detects an outage. Generator batteries last 3 to 5 years under normal conditions. The weekly exercise cycle keeps the battery charged, but batteries degrade with age regardless of use. Replace the battery proactively every 4 years rather than waiting for a failed start during an outage. A dead battery is the most common reason a generator fails to start when needed.
Professional Service vs. DIY
Most homeowners can handle the visual inspection, air filter check, and battery terminal cleaning themselves. Oil changes, spark plug replacement, and more involved maintenance can be performed by a handy homeowner with basic tools, or by a certified generator technician. For homeowners who prefer professional service, most generator dealers and many electricians offer annual maintenance contracts ranging from $200 to $400 per year that cover all scheduled maintenance items.
Maintenance Cost
Annual maintenance costs for a residential standby generator are modest. A DIY oil and filter change costs approximately $30 to $60 in materials. A manufacturer maintenance kit (oil filter, air filter, spark plugs) costs $40 to $80. A professional annual service visit costs $200 to $400. These costs represent less than 1% of the generator purchase price annually and are a small investment in ensuring the system performs when you need it most.
Need maintenance supplies for your generator? Call (800) 674-9019 or browse maintenance kits and accessories in our online shop. Browse generators at our Generac home standby generators collection.