What is the difference between a foam gun and cannon?

Thinking about washing your car with foam but confused by the tools? Choosing the wrong one can lead to frustration, weak results, and wasted money. Let me simplify it for you.

The main difference is the power source: a foam gun¹ connects to a standard garden hose, while a foam cannon² attaches to a pressure washer³. This results in the cannon producing much thicker foam due to the higher pressure.

Over the past 15 years manufacturing these products, I've seen a lot of confusion around this topic. The difference seems small, but it completely changes the user experience, the quality of the foam, and even where you are likely to buy the tool. Many people buy a foam gun expecting the super-thick, shaving cream-like foam they see in videos, only to be disappointed. That famous thick foam⁴ is almost always created by a foam cannon and a pressure washer. Let's break down why these two tools are so different, so you can choose the right one for your needs and know exactly what to expect.

Which tool creates better foam?

You've seen videos of cars covered in a thick blanket of foam. If you want that result, the tool you choose is critical, as one simply doesn't have the power to achieve it.

A foam cannon² creates significantly thicker, richer foam than a foam gun¹. This is because the high pressure from a pressure washer³ is far more effective at mixing water, soap, and air into a dense lather.

The secret to amazing foam is pressure. A foam cannon leverages the intense power of a pressure washer (typically 1000 PSI or more). This high-pressure water stream blasts through an orifice, creating a powerful vacuum that aggressively pulls soap and air into the mixing chamber. The result is that thick, clinging foam that lifts dirt effectively. A foam gun, on the other hand, only has the pressure from your home's tap water (around 40-60 PSI). While it does a decent job of creating soapy suds, it lacks the force to produce that same rich consistency. The foam from a gun is more watery and runs off the surface faster. I want to be clear: the foam from a gun is absolutely enough to clean a car safely and effectively. But if your goal is achieving that super-thick foam you see online, you need the power that only a foam cannon and pressure washer can provide.

Why are foam guns so hard to find online?

You might notice that foam cannons are everywhere on Amazon and e-commerce sites, but foam guns are less common. This isn't an accident; it's a lesson I've learned from watching the market for years.

Foam guns sell poorly online because of an expectation mismatch⁵. Customers see thick foam⁴ in marketing, buy the convenient hose-end gun, and are disappointed by the thinner suds⁶, leading to bad reviews and returns.

The biggest strength of the foam gun is its biggest weakness in the online world: convenience⁷. It's incredibly easy to use—just click it onto your garden hose and go. But an average customer doesn't understand the physics of water pressure. They buy the gun expecting a professional-grade foam show. When they get thin suds, their immediate reaction is "this product is cheap" or "it doesn't work." This leads to a high rate of negative reviews, which is poison for any product on a competitive e-commerce platform. Because of this, only a few very powerful sellers with established brands can successfully manage to sell them online. In contrast, you can find foam guns selling very well in physical stores like supermarkets or auto parts shops. There, the product's convenience can be explained in person, managing expectations before the sale. It’s a fascinating example of how customer perception⁸ shapes a product's success in different sales environments.

Which foam tool is easier to use?

When you're deciding between these tools, the final choice often comes down to balancing results with effort. One is built for absolute simplicity, while the other is built for maximum performance⁹.

The foam gun is far easier to use. You simply attach it to your garden hose. The foam cannon requires a pressure washer, power cords, and more setup time, making it a more involved process.

There is no contest when it comes to convenience. The foam gun is the clear winner for ease of use. You can be ready to wash your car in under a minute. There are no machines to wheel out, no power cords to unwind, and no complex connections to make. It's the perfect solution for a quick, no-fuss wash. The foam cannon, however, demands a more significant commitment. You need to get your pressure washer out, connect it to a power outlet and your water supply, attach the high-pressure hose, and then fit the foam cannon. While the results are superior, the preparation is more complex and time-consuming. This difference in setup is the core trade-off you must consider.

Ease of Use vs. Performance

Conclusion

For convenience and speed with adequate foam, choose a foam gun. For the thickest, professional-quality foam that you see online, you must use a foam cannon with a pressure washer.