Homeowners, do you want to keep the electricity on in your home when the grid utility power fails? Rather than install a costly permanent backup system, you can choose between two affordable types of portable generators – diesel or gasoline. (Either one is also perfect for powering isolated homes and job sites where grid power is not an option.) Compare the performance of a diesel vs a gas generator and choose the kind that’s best for your home.

Diesel vs. Gas Generator: Efficiency

One advantage that portable diesel generators have over the gas variety is their fuel efficiency. Diesel generators use less fuel than their gasoline-powered counterparts. The reason is this: In a diesel generator, compression ignites the fuel. Fuel and air are introduced into the engine separately. Only the air is compressed, which allows the engine to run more efficiently by using less fuel.

By contrast, gasoline engines mix the fuel and air together in a carburetor prior to compression, reducing fuel efficiency.

Because portable diesel generators are more fuel efficient, they will run longer on the same amount of fuel. As a result they will cost less to operate and provide uninterrupted power to your home or facility.

Diesel vs. Gasoline: Noise & Heat

Time was, older models of portable diesel generators were famously noisy, making them unsuitable for use in high-density neighborhoods. However, contemporary models run more quietly and require less maintenance than gasoline generators because there are no carburetors or spark plugs. An 1800-rpm water-cooled diesel generator will run for 12,000 to 30,000 hours before it requires major maintenance. By comparison, similar gasoline generators will need service after 6,000 to 10,000 hours of operation.

Also, diesel generators will need to be replaced less often. They’ll last longer since gasoline burns hotter than diesel, which will result in a shorter life span for the equipment.

Air-Cooled or Liquid-Cooled

Generators are either air-cooled or liquid-cooled. Whether the portable generator is diesel or gasoline powered, liquid-cooled units are typically more expensive and used for larger projects.

Homeowners who want a portable generator for sporadic, short-term power outages may want to consider an affordable air-cooled portable gasoline generator. For long-term or extended use, such as for job sites and remote homesteads, a liquid-cooled, portable diesel generator – while more expensive -- may be the best choice.

The Right Generator Type: It’s Your Choice

Smaller units are most suitable for small single-family homes where few appliances will be drawing on the energy. Larger homes or families requiring more power for specialized essential needs, such as medical equipment, may need a generator with more output. But be aware: the higher the wattage of a portable generator, the higher the price tag, as well.

Buying the right portable diesel generator or gasoline generator is easy once you have decided if it will be used for extended or short periods of time, the number of appliances that it needs to power and of course, your budget. Contact a licensed electrician for guidance as well as expert installation. 

Updated December 26, 2018.