We wished we had a definitive answer to that question. It’s such a difficult question to answer as there are so many variables to consider in killing or removing contaminants from a surface with steam.
What other steam companies and I would agree on is that steam is an excellent way to clean. It’s fast; there are no chemicals used; the degree of “clean” always seems to be better than cleaning with a cloth and a spray-on type cleaner. Steam has become a preferred method of cleaning for many businesses and homeowners alike. But getting back to disinfection and killing of a virus…….. Can steam do it? Is it hot enough?
Many scientists will tell you that high temperatures can kill germs. Many say that germs thrive in temperature environments between 40-140 degrees Fahrenheit. That is why it’s important to refrigerate food and cook at high temps. And boiling water is generally very effective in killing off most bacteria in foods. To produce steam, we have to go far above the boiling point of water (212 degrees), so wouldn’t it make sense that steam can kill a virus?
Many steamers, even the less expensive, non-commercial ones, can produce steam at close to 250 degrees. And the higher the pressure the steamer can reach, the higher the temperature will be. Pressure increases with heat. And heat increases the pressure. On our Chief Steamer 75 commercial machine, we are at 85 PSI in the boiler, and that equates to roughly 310 degrees of superheated water inside the boiler. And our other machines are even higher. Sounds like enough, right? Just blast any surface with a little of this superheated steam, and ZAP…..virus, germs, and bacteria are all gone!
But not so fast……..
Here is where the very grey area comes in. It matters greatly how you do it if you want to have a chance at this. Many customers, when they first receive their steamer (regardless of the model), will question that the steam is not that hot. When I hear that, I know EXACTLY what they are doing. The customer is spraying steam on their hands, and they can actually handle the heat. Why would it feel only warm, and why can you stand the heat? The reasons are numerous.
Let’s start with the heat in the boiler. On our Chief Steamer 75, it will be about 310 for argument sake at 85 PSI. That is IN the boiler. But the steam then needs to escape the boiler and rush through an empty and cool hose. As it travels, the steam starts to cool. We estimate about a 50-degree drop by the time it exits. This is directly at the tip of the wand, and after the steam hose has been “primed” and only hot steam is escaping. If the steam wand is held even a few inches from a surface, it has cooled even more from hitting the atmosphere. It still is pretty hot, but how hot at that point? Can it still disinfect a surface if held 2, 3, or 4 inches away?
But if we estimate the steam is still at about 250 degrees on exit, exactly at the tip of the wand, it still will seem its plenty hot to kill a germ, bacteria, or a virus. HOWEVER……. now it’s about technique and knowing how fast steam will cool as it exits the nozzle. This is why the “test” that a customer will do when they hold their hand 5 inches away and spray steam that they say it’s not that hot. This is actually a very wrong technique in cleaning. Spraying steam all overlooks really cool and puts on a good show. But that method is not the best cleaning technique. The steam needs to be applied directly on the surface and not allowed to escape. And to sanitize, it needs to be there for at least a few seconds. But this is also debatable in how long steam needs to be applied to kill the virus on the surface. To be the most successful in steam cleaning, it is really about technique.
A better way in almost all cases is to use a brush on the nozzle. All steamers come with brushes. You choose the one you like. But a brush gives you a much better chance. The brush and gentle (or aggressive in some cases) scrubbing action will get you there way faster than just spraying steam and expecting built-up grime and dirt to magically go away. By using a brush, you can trap the steam on, or into, the surface and retain far more heat. By using a cloth or pad over a brush, this will trap the heat even more. NOW try touching a microfiber pad that has just been cycled on for 20 seconds or more. It WILL now burn your hand. That is the difference. You have trapped the heat and not let it escape as easily. It stays hotter and cleans far more effectively than just spraying steam on a surface from far away.
Next, you should gently scrub. It will get you there much quicker. And the rate of speed at which you move along the surface will make a HUGE difference. Move slower, the heat stays there longer, and you have a much better case of killing anything and cleaning better. Move along very fast, you will save time, but you will not clean and sanitize as effectively.
To sum it all up…… steam may very likely be able to kill a virus, maybe even the Coronavirus. It most likely can kill germs and bacteria. But going in, you have to know what you are doing with the steamer and understand how this all can work in your favor to get the job done. And combine proper technique with a proven sanitizing cleaner lightly sprayed on a surface to enhance the cleaning and disinfection, and now you have the absolute BEST shot at getting it right. But do it wrong, and there is a strong likely hood that you did not kill anything. It may be clean, cleaner, spotless……. but NOT sanitized. The absolute BEST steamer (whatever you may think it is) may not be killing any germs, viruses, bacteria at all if you do it wrong. And a cheaper, entry-level steamer that has far lower specs may even get the job done if the user knows how to correctly use the machine.
But even if its all done right and the technique is flawless, it’s still not known if that surface is 100% sanitized and virus free. It’s impossible to prove unless this is done in a laboratory. So be careful of what you may claim in your steam cleaning. But in my home, I will use steam, use it the best way I know how, and take my time. And while I will not, or cannot claim I have truly disinfected a surface, I will be far more confident that it’s as close to sanitized as possible based on what we know about what extreme heat can do.