Most of us don't give much thought to steam. Unless it burns us, we probably dismiss it from our minds as quickly as it mysteriously dissipates into the air from our hot cup of morning joe. But this ubiquitous gas is profoundly useful. Not only do power plants use steam to turn turbines and produce electricity, but steam is also a very useful cleaning tool.
Steam is a tried and true sanitizer. And unlike some abrasive cleaners, steam is both penetrating and gentle at the same time. It effectively sanitizes because it can reach high temperatures (above the boiling point of water) in pressurized atmospheres. And, by effectively rehydrating and breaking the bonds of muck and dirt, it's highly effective at spot-cleaning and deodorizing without all that rough treatment. And irons, of course, use steam to work the wrinkles out of fabrics when dryers don't cut it.
Steam is such an appropriate fabric cleaning tool that, in a way, it's surprising washing machines and dryers haven't used it before. Realizing the benefits of steam cleaning technology, several appliance brands, such as Maytag, LG, Kenmore, Whirlpool and Samsung, are beginning to offer steam washers and steam dryers (and even two-in-one units). And, as an added bonus, most of these models are energy and water efficient.
It stands to reason that steam, as the gaseous state of water, will moisten things. So it may seem odd that it could also dry things. As it turns out, the term "steam dryer" is somewhat of a misnomer for these particular appliances. Indeed, throwing already dry items into these steam dryers will make them wetter during the process before drying them again. Though it seems illogical for a dryer to apply more moisture to clothes, it's actually useful, reducing wrinkles and eliminating odors.
Read on to learn the steamy details about these new features in washers and dryers and whether they could save you trips to the drycleaners.
How a Steam Washer Works
In a washing machine, steam and water form a dynamic duo. Steam complements water in the cleaning process by keeping the fabrics soft and wrinkle-free. One patent filed by LG Electronics, the company that put out the first home steam washer, explains the different advantages that steam can offer when applied in three different stages of a washing machine cycle:
- Pre-wash phase: While the water loads into the wash tub, the steam works with the water to help soak the fabrics more thoroughly.
- During the washing phase: If added while the detergent is mixed with the water, the steam increases the temperature of the wash tub to improve the cleaning power, which also helps to activate the detergent. It does this by dissolving the detergent more effectively, to get the most out of it as possible.
- Post-wash phase: Steam added after washing lends more high temperatures to the tub to sterilize the clothes. It also softens the clothes to remove hard wrinkles that formed while the clothes tossed in the tub.
The patent goes on to explain that when some fabrics get wet and hot, their very properties change. Although this state allows them to be thoroughly cleaned, it also means they may become hard and wrinkle. The penetrating steam post-wash phase counteracts this hardening.
Washing machines can apply steam in a few different ways. Though some heat the water in the tub directly to create steam, other models utilize a steam generator that heats up water in a separate compartment. After converting the water to steam, the steam generator sends the steam through a tube to a nozzle. The nozzle subsequently releases pure steam into the tub. Which method works best may depend on the model and your needs. If your clothes have tough stains, perhaps you should read the fine print to find which model gets the hottest.
Often, steam washing machines have options to add steam to normal cycles, in addition to the special cycles that already incorporate steam. But the user isn't tied to steam washing, which is good given that steam lengthens the cycle. Kenmore sells a steam washer that incorporates a self-cleaning steam option. Though many people don't think about cleaning washers themselves, the user manual recommends running this cycle once a month.
LG offers certain washers that are specially designed for those with severe allergies. These machines use what they call an "Allergiene" cycle that uses steam to sanitize fabrics of such things as dust mites and pet dander [source: LG]. It can do this because the high temperatures of the steam break up allergens effectively.
Steam washing machines use less power and consume less water than conventional models. A little bit of water can produce a lot of steam, which expands to take up more volume. Steam washers, then, don't need as much energy to heat as many gallons of water as other models.
But washers are only half of the story. Read on to find out how dryers may replace your drycleaning.
How a Steam Dryer Works
Conventional dryers apply heat to wet clothes to evaporate the moisture, or turn the liquid water into a gas. This resultant gas is, of course, steam. So why design a dryer to apply more steam to clothes?
Even though steam is a byproduct of drying, applying steam at the right times to wet clothes or dry clothes has advantages. Steam penetrates and moistens clothes deeply, which has a softening effect that reduces wrinkles. Also, because steam can reach high temperatures, it effectively sanitizes clothes, which helps to eliminate those nasty smells.
Steam can offer similar benefits to completely dry clothes. For instance, if your favorite shirt reeks of that smoky bar you went to last night and you don't have time for a full wash the next morning, you can throw it in an LG steam dryer for a quick 20-minute steaming -- what LG calls the SteamFresh cycle. Without using liquid water or even detergent, the steam alone can refresh the item. But make sure that shirt doesn't have any stains before you drop it in this cycle because the hot steam might set them.
Steam dryers can also reduce the wrinkles in dried clothes. This is especially helpful if you're not around when the dryer cycle ends, and you're clothes have hardened with wrinkles by the time you get to them. Running the dryer again with steam could soften and de-wrinkle them.
Not all steam dryers were created equal. They apply different steam in different ways. Maytag models don't release a stream of pure steam, but rather a fine mist to the clothes. The heat in the dryer then raises the temperature of the mist to turn it to steam. Other dryers use a steam generator to release pure steam to the clothes.
In the steam dryers we've discussed so far, steam doesn't do any drying per se, but rather refreshes and reduces wrinkles. The dryer simply releases steam during the cycle before drying the items again. But as odd as it sounds, steam could potentially dry fabrics, too. An advanced drying technique involves using superheated dry steam, which is steam that doesn't contain any liquid water. This kind of steam is purely gas and invisible to the human eye, as opposed to wet steam, which suspends visible water droplets.
By superheating dry steam to a high enough temperature, machines can use steam to dry items. The very hot steam effectively heats moisture to the evaporation point [source: van Deventer]. Then, the dryer circulates the resulting evaporated moisture out of the system and repeats the process. Though intended for industrial dryers, perhaps the technology of superheated steam dryers will eventually make its way into mass-produced home dryers.
If you crave the benefits of steam drying but can't afford to cough up the money for a new top-of-the-line dryer, there are easy alternatives. For instance, merely hanging a wrinkled shirt in your bathroom while you take a steamy-hot shower will release the crinkle. You can also throw the item in your dryer along with a wet item. The wet item will produce steam to de-wrinkle the dry item.
In the end, steam washers and dryers simply add more options and flexibility to solve your laundry quandaries. To get more dirt on cleaning methods and steam technology, take a gander at the links on the next page.
Related HowStuffWorks Articles
More Great Links
- Kenmore. "Kenmore Elite: HE5t Steam Front Loading Automatic Washer Use & Care Guide." Sears Roebuck and Co. (June 20, 2008) http://download.sears.com/own/47781e.pdf
- LG. "Front Loading Steam Combo User's Guide & Installation Instructions." LG Electronics. (June 20, 2008) http://demandware.edgesuite.net/aabh_prd/on/demandware.static/ Sites-Appliance-Site/Sites-CompactAppliance_Primary/default/v1213859301675/ pdf/ownersmanuals/lg/LG_WM3988HWA_manual.pdf
- LG. "LG Electronics Unveils Industry-First Allergen-Reducing Steam Washer." LG Electronics. Jan. 15, 2008. (June 20, 2008) http://us.lge.com/aboutus/pressdetail/detail/press_Home%20Appliances_358.jhtml
- LG. "Steam Washer." LG Electronics. Promotional Video. (June 20, 2008) http://us.lge.com/md/product/contents/Washer/steamwasher_popup.html
- Maytag. "Bravos Steam Fabric Care System Care System Gas Dryer Use & Care Guide." Maytag. (June 20, 2008) http://www.abt.com/images/products/PDF_Files/mgd6600twh_manual.pdf
- OH, Soo Young, et al. "Steam Washing Method for Washing Machine and Washing Machine with the Same." International Patent WO/2006/104310. Pub. May 10, 2006. (June 20, 2008) http://www.wipo.int/pctdb/en/wo.jsp?wo=2006104310&IA=WO2006104310&DISPLAY=STATUS
- Son, Chang Woo, et al. "Laundry machine and control method thereof." U.S. Patent 20080141553. Filed Oct. 31, 2007. Pub. June, 19, 2008. (June 20, 2008) http://www.freepatentsonline.com/US20080141553.html
- van Deventer, H.C. "Industrial superheated steam drying." TNO Environment, Energy and Process Innovation. June 2004. (June 20, 2008) http://gasunie.eldoc.ub.rug.nl/FILES/root/2004/3337003/3337003.pdf