Air-cooled or water-cooled generator: which one?

An air-cooled generator sheds engine heat with a fan: it is simple, compact and affordable, ideal for occasional use; our range runs from 2 kW to 15 kVA. A water-cooled generator uses a radiator and coolant to run long hours under heavy load; our Perkins-engine range runs from 13 to 2,000 kVA.

How does each cooling system work?

An air-cooled generator blows air from a fan over the engine to carry the heat away. A water-cooled generator circulates coolant between the engine and a radiator, much like a car.

The coolant circuit keeps the engine at a steady temperature, even under heavy load for long hours. Our datasheets give its capacity: 6 litres for the 13 kVA set and 12.6 litres for the 100 kVA set.

An air-cooled generator has no radiator and no coolant to check. It is designed for intermittent running: it needs time to cool down between long spells of operation.

Air-cooled or water-cooled: what are the differences?

The table repeats the comparison from our finder, with the figures from our range added.

The small petrol and inverter sets are rated in kW: 2.0 to 7.0 kW for petrol and 2.3 to 5.0 kW for the inverters. The air-cooled diesels are rated in kVA, from 5 to 15 kVA.

How different are they in size and weight?

Our smallest air-cooled diesel and our smallest water-cooled set show the gap. The Bison BS7500DSE, a 5 kVA air-cooled diesel, measures 95 × 57 × 85 cm and weighs 151 kg. Our 13 kVA soundproof set with a Perkins 403A-15G1 engine, which is water-cooled, measures 198 × 78 × 122 cm and weighs 850 kg.

A water-cooled set is therefore a fixed installation on flat, stable ground. Our guide Installing a generator safely covers location and ventilation.

Between 13 and 15 kVA, which should you choose?

Between 13 and 15 kVA, both technologies exist in our range. On the air-cooled side, the Brux BX16000DSE3-3D delivers 15 kVA in three-phase. On the water-cooled side, our 13 and 15 kVA sets with Perkins engines are also three-phase.

• Choose water cooling if the generator will run several hours a day.
• Choose air cooling for occasional backup, when size and weight matter.

Our finder switches cooling type in two cases. First, when the cooling you chose cannot cover your need. Second, when the suggested set would be more than 1.6 times your need and the other range has a closer fit.

Which cooling type for load-shedding in Kinshasa?

For load-shedding of several hours a day, choose a water-cooled set: it is designed for long, continuous hours. For a few short outages, an air-cooled set is enough, provided it covers the power you need.

Power matters as much as cooling. For a house, see our guide What size generator for a house in Kinshasa?. Fuel matters too: see diesel, petrol or inverter.

How does the finder help you choose?

The first step of our finder asks this very question: air-cooled or water-cooled? It also shows the comparison above. Use the finder to work out your generator size; it then lists the suitable models from both ranges.

You can also browse our air-cooled silent diesel generators and our water-cooled diesel generators.

Frequently asked questions

Is an air-cooled generator suitable for long hours every day?

No. It is made for intermittent use, with breaks to cool down. For several running hours a day, choose a water-cooled set.

Does a water-cooled generator need more maintenance?

It has more parts to check: the coolant level, the radiator and its hoses. The service intervals are those in the engine manufacturer's manual.

Sources: manufacturers' datasheets (Perkins engines, Bison and Brux generators), MK Energies & Services finder comparison.