Diesel Generators vs. Petrol Generators: Which is Right for You?

Whether you are powering a home, a piece of portable construction equipment, a recreational vehicle, an outdoor project site or a farm, both diesel and petrol generators can provide the power you need to keep the lights on and get the job done. But which type of generator is superior, and which is preferable for different applications?


While most of us are used to thinking of diesel as the 'more expensive' type of fuel, compared to petrol, that isn't necessarily the case when it comes to generators. Diesel fuel may still be more expensive than petrol, but diesel generators are also a good deal more fuel efficient than their petrol counterparts, generally burning about 50% as much fuel over any given period of time. Therefore, portable diesel generators are usually less expensive over time than petrol generators.

This fuel efficiency—and the resulting edge that diesel generators have in power production—is the major advantage of going diesel over choosing petrol. Naturally, the benefits that diesel generators have in both fuel efficiency and power production are better observed in situations where generator use is consistent and power needs are high. Construction sites and farming equipment, for instance, place very high demands on their generators. As a result, companies working in these industries will almost always use diesel generators, simply because they can produce greater levels of power at lower cost.


Petrol generators, on the other hand, are arguably a better option for infrequent or temporary use. This is true for multiple reasons. First of all, petrol generators are generally less expensive—and available in more models and price ranges—than diesel generators, one of the few benefits of their reduced power. Petrol generators also run quieter and produced less harmful carbon dioxide fumes than their diesel brethren. Both of these characteristics may be determining factors if you are buying a generator as an intermittent-use backup power option for your home: having a generator that makes less of a racket and produces a lower amount of smelly fumes can simply make using a generator a more pleasant experience.

In addition, if you are only using a generator for temporary, intermittent or low-load applications, then you wouldn't really see the benefits of a diesel generator anyway. Diesel generators are more fuel-efficient, but diesel also costs more than petrol, so you are less likely to notice the savings if you aren't making consistent or heavy-load use of your generator. Petrol generators also tend to break down faster than diesel generators because they run hotter, but you can still get many years of good use out of them if your generator applications aren't particularly intensive or high-demand. Diesel generators also don't tend to hold up very well if they aren't used frequently, so that's another point in favor of petrol.

The Verdict

Ultimately, most industrial companies would probably defend diesel generators as the superior choice over petrol generators, but the answer to which is best really just comes down to what your needs are and what you will be using the generator for. Those with higher power demands will likely prefer a heavy-duty Airman diesel generator, while those with more modest needs can probably get by with a modest (and modestly priced) portable petrol generator.

Need more help deciding which type of generator is right for you? Whether you are choosing between a 6kva generator and a 10kva generator, or between a portable diesel generator and a portable petrol generator, Generator Boys can help! As SA's experts on petrol and diesel generators, we can give you advice on which type is the right choice for you.