How often does my whole home generator need maintenance, and what does maintenance include?

Colorado-Specific Maintenance Considerations

Denver Front Range conditions add a few wrinkles to standard generator maintenance. Colorado’s altitude (5,280 feet in Denver, higher in foothills communities) reduces air density, which affects combustion efficiency. Most modern generators have electronic governors that compensate, but it’s worth confirming your unit’s fuel-air mixture is calibrated for altitude — an engine tuned for sea level will run rich at elevation. Colorado also experiences intense temperature swings: a generator sitting through a -10°F January night needs its oil viscosity matched to cold-start conditions, and a battery that tests fine in summer can fail to crank in extreme cold.

When to Schedule Service Beyond Annual Maintenance

If your generator has run for an extended period during a real outage — say, 48 hours or more — schedule a service visit sooner than the annual interval. Extended run hours accelerate oil degradation and filter loading. The same applies if the unit shows any fault codes, fails to complete a self-test, or makes unusual sounds (knocking, excessive vibration, governor hunting) during operation. Address these promptly; they rarely fix themselves.

Done’s electricians install and service standby generators throughout the Denver metro, including annual maintenance programs that keep your backup power ready when Colorado weather demands it. Learn more on our backup power page, or check out our Care Club maintenance membership for a cost-effective way to keep all your home systems — electrical, HVAC, and plumbing — on a regular service schedule.

The Weekly Self-Test Exercise Cycle

Most standby generators are programmed from the factory to run a short self-test once a week — typically 12 minutes at a scheduled time. This cycle lubricates engine seals, charges the starter battery, exercises the transfer switch contacts, and alerts you to any faults via the control panel. You’ll hear the generator start briefly; that’s normal and intentional. If the self-test light or app notification shows a fault code, don’t ignore it — these alerts often catch developing problems (low oil pressure, battery voltage dropping, fault in the transfer switch) before they become a no-start at the worst possible time.

Colorado-Specific Maintenance Considerations

Denver Front Range conditions add a few wrinkles to standard generator maintenance. Colorado’s altitude (5,280 feet in Denver, higher in foothills communities) reduces air density, which affects combustion efficiency. Most modern generators have electronic governors that compensate, but it’s worth confirming your unit’s fuel-air mixture is calibrated for altitude — an engine tuned for sea level will run rich at elevation. Colorado also experiences intense temperature swings: a generator sitting through a -10°F January night needs its oil viscosity matched to cold-start conditions, and a battery that tests fine in summer can fail to crank in extreme cold.

When to Schedule Service Beyond Annual Maintenance

If your generator has run for an extended period during a real outage — say, 48 hours or more — schedule a service visit sooner than the annual interval. Extended run hours accelerate oil degradation and filter loading. The same applies if the unit shows any fault codes, fails to complete a self-test, or makes unusual sounds (knocking, excessive vibration, governor hunting) during operation. Address these promptly; they rarely fix themselves.

Done’s electricians install and service standby generators throughout the Denver metro, including annual maintenance programs that keep your backup power ready when Colorado weather demands it. Learn more on our backup power page, or check out our Care Club maintenance membership for a cost-effective way to keep all your home systems — electrical, HVAC, and plumbing — on a regular service schedule.

What Annual Maintenance Includes

A comprehensive generator tune-up covers the engine, the electrical systems, and the transfer switch that connects the generator to your home. Specifically, a qualified technician will:

• Change the engine oil and filter — generator engines accumulate hours from weekly exercise cycles and actual outage use; fresh oil protects internal components
• Replace the air filter — Colorado’s dry, dusty environment means air filters clog faster than in more humid climates; a clogged air filter causes rich-running conditions and carbon buildup
• Replace the spark plugs — worn plugs cause misfires, hard starting, and reduced power output
• Inspect and test the battery — the starter battery is the most common single point of failure; if it won’t crank the engine, nothing else matters
• Check coolant level and condition — on liquid-cooled units (typically larger whole-home generators, 20kW and up)
• Inspect the fuel system — check gas pressure on natural gas units; inspect propane connections and regulator on LP systems
• Test the automatic transfer switch — verify it detects a simulated outage, transfers load to the generator, and transfers back cleanly on power restoration
• Load bank test (as needed) — running the generator under a simulated load confirms it can actually deliver its rated wattage, not just idle

The Weekly Self-Test Exercise Cycle

Most standby generators are programmed from the factory to run a short self-test once a week — typically 12 minutes at a scheduled time. This cycle lubricates engine seals, charges the starter battery, exercises the transfer switch contacts, and alerts you to any faults via the control panel. You’ll hear the generator start briefly; that’s normal and intentional. If the self-test light or app notification shows a fault code, don’t ignore it — these alerts often catch developing problems (low oil pressure, battery voltage dropping, fault in the transfer switch) before they become a no-start at the worst possible time.

Colorado-Specific Maintenance Considerations

Denver Front Range conditions add a few wrinkles to standard generator maintenance. Colorado’s altitude (5,280 feet in Denver, higher in foothills communities) reduces air density, which affects combustion efficiency. Most modern generators have electronic governors that compensate, but it’s worth confirming your unit’s fuel-air mixture is calibrated for altitude — an engine tuned for sea level will run rich at elevation. Colorado also experiences intense temperature swings: a generator sitting through a -10°F January night needs its oil viscosity matched to cold-start conditions, and a battery that tests fine in summer can fail to crank in extreme cold.

When to Schedule Service Beyond Annual Maintenance

If your generator has run for an extended period during a real outage — say, 48 hours or more — schedule a service visit sooner than the annual interval. Extended run hours accelerate oil degradation and filter loading. The same applies if the unit shows any fault codes, fails to complete a self-test, or makes unusual sounds (knocking, excessive vibration, governor hunting) during operation. Address these promptly; they rarely fix themselves.

Done’s electricians install and service standby generators throughout the Denver metro, including annual maintenance programs that keep your backup power ready when Colorado weather demands it. Learn more on our backup power page, or check out our Care Club maintenance membership for a cost-effective way to keep all your home systems — electrical, HVAC, and plumbing — on a regular service schedule.

A whole home standby generator should receive a professional maintenance service once a year, with weekly or bi-weekly self-test cycles run automatically by the unit’s built-in controller. Annual maintenance is not optional — generators are internal combustion engines, and like any engine they need fresh oil, new filters, and a thorough inspection to remain reliable when you actually need them. Skipping maintenance is how generators that look fine on the outside fail to start during the first real outage in years.

What Annual Maintenance Includes

A comprehensive generator tune-up covers the engine, the electrical systems, and the transfer switch that connects the generator to your home. Specifically, a qualified technician will:

• Change the engine oil and filter — generator engines accumulate hours from weekly exercise cycles and actual outage use; fresh oil protects internal components
• Replace the air filter — Colorado’s dry, dusty environment means air filters clog faster than in more humid climates; a clogged air filter causes rich-running conditions and carbon buildup
• Replace the spark plugs — worn plugs cause misfires, hard starting, and reduced power output
• Inspect and test the battery — the starter battery is the most common single point of failure; if it won’t crank the engine, nothing else matters
• Check coolant level and condition — on liquid-cooled units (typically larger whole-home generators, 20kW and up)
• Inspect the fuel system — check gas pressure on natural gas units; inspect propane connections and regulator on LP systems
• Test the automatic transfer switch — verify it detects a simulated outage, transfers load to the generator, and transfers back cleanly on power restoration
• Load bank test (as needed) — running the generator under a simulated load confirms it can actually deliver its rated wattage, not just idle

The Weekly Self-Test Exercise Cycle

Most standby generators are programmed from the factory to run a short self-test once a week — typically 12 minutes at a scheduled time. This cycle lubricates engine seals, charges the starter battery, exercises the transfer switch contacts, and alerts you to any faults via the control panel. You’ll hear the generator start briefly; that’s normal and intentional. If the self-test light or app notification shows a fault code, don’t ignore it — these alerts often catch developing problems (low oil pressure, battery voltage dropping, fault in the transfer switch) before they become a no-start at the worst possible time.

Colorado-Specific Maintenance Considerations

Denver Front Range conditions add a few wrinkles to standard generator maintenance. Colorado’s altitude (5,280 feet in Denver, higher in foothills communities) reduces air density, which affects combustion efficiency. Most modern generators have electronic governors that compensate, but it’s worth confirming your unit’s fuel-air mixture is calibrated for altitude — an engine tuned for sea level will run rich at elevation. Colorado also experiences intense temperature swings: a generator sitting through a -10°F January night needs its oil viscosity matched to cold-start conditions, and a battery that tests fine in summer can fail to crank in extreme cold.

When to Schedule Service Beyond Annual Maintenance

If your generator has run for an extended period during a real outage — say, 48 hours or more — schedule a service visit sooner than the annual interval. Extended run hours accelerate oil degradation and filter loading. The same applies if the unit shows any fault codes, fails to complete a self-test, or makes unusual sounds (knocking, excessive vibration, governor hunting) during operation. Address these promptly; they rarely fix themselves.

Done’s electricians install and service standby generators throughout the Denver metro, including annual maintenance programs that keep your backup power ready when Colorado weather demands it. Learn more on our backup power page, or check out our Care Club maintenance membership for a cost-effective way to keep all your home systems — electrical, HVAC, and plumbing — on a regular service schedule.