Guide
Generator service cost: what you are actually paying for
Updated
Two quotes for servicing the same standby set can differ by a factor of three and both be honest. The difference is almost always what is in scope, not what the labour costs.
Why there is no honest average
Generator servicing covers everything from oil and filters on a small standby set to a full annual regime with load bank testing, fuel sampling and transfer switch proving on a critical installation. There is no published UK dataset of generator service prices we could average without inventing it, so we publish the drivers instead and let real providers price your plant.
The scope questions that explain the gap
- Is load testing included? A service that runs the set off-load for twenty minutes is a fraction of the cost of one that proves the set under load. Both get called an annual service.
- Is fuel in scope? Sampling, polishing and tank cleaning are separate jobs and often the biggest surprise on inherited plant.
- Are consumables included or extra? Oil, filters, coolant, batteries and belts. Ask which are in the price and which are quoted on condition.
- Is the transfer switch covered? Proving an automatic changeover on simulated mains failure involves the electrical installation and someone authorised to switch.
- What is the response promise? Response cover is a separate purchase from planned maintenance, and it is where contract prices really diverge.
How to make quotes comparable
- Send the same information to everyone. Engine and alternator make and model, kVA rating, hours run, fuel tank size, site access and permit requirements.
- Ask for a price per set with a task list. Not a site total, and not a service tier name without contents.
- Ask for labour rates separately. Standard hours, out of hours, callout, and travel. That is what breakdowns will actually cost you.
- Ask what the report contains. Readings, not ticks, and a dated list of recommended work with priorities.
The cheapest annual service is usually the one that proves the least. If the set exists to protect something expensive, buy the test that proves it works, not the visit that proves it starts. See load bank testing.