Running costs & maintenance

Running costs

The national grid's electricity costs you around 20c per kWh. Running a small generator is never going to be as cost effective as that. For a start, a petrol-powered generator uses a heavily taxed fuel. And small generators aren't as efficient as industrial-scale plant.

• Running costs for diesel models are around 35c per kWh.
• Four-stroke models are more than double that - about 85c per kWh.
• And to run a two-stroke, you can expect to pay up to $1.20 per kWh.

Fuel consumption figures are not particularly well stated in manufacturers' specification sheets (and often they're non-existent), so for these figures we made some assumptions.

Maintenance

Generator maintenance can be required much more frequently than you might think.

It doesn't take that long to clock up engine-running hours. Let's say you get snow-bound, without power, like many Canterbury farmers last winter. If you run a generator for 6 hours per day for a week, you'll clock up 42 hours run time. At that point the generator may require servicing - or even be overdue.

Oil-change intervals for four-stroke petrol models vary, depending on the model: they're usually from every 25 to every 100 hours of operation. Filters, spark plugs, and carbon brushes (for non-brushless models) also require attention at regular intervals.

Oil, filter and spark plug changes should be within the ability of anyone who's moderately handy. Alternatively, you could take the generator to an outdoor-powertool shop.

If you ignore servicing, you'll pay with reduced engine reliability and lifespan.