Warm Mist Humidifiers.The first decision you'll need to make is whether to buy a warm mist humidifier or a cool mist humidifier.
Warm mist humidifiers are just that: humidifiers that put out warm steam or mist after bringing water to a boil. Alternatively known as steam humidifiers or vaporizer humidifiers, they're among the cheapest; the Vicks Warm Mist V745A, for example, has a starting price of $30.
Humidifier Filters.Some cheap humidifiers require filters. Among those we researched, the Honeywell HCM-630 QuietCare, Holmes HM630-U, and Vornado HU1-0021-28 have humidifier filters that should be changed every four to eight weeks, depending on the model; replacement filters cost about $10. The Crane EE-5301, Vicks V745A, and Holmes HM495-UC, on the other hand, do not use humidifier filters -- a design feature that makes for easier maintenance and is often lauded by consumers in their reviews of cheap humidifiers.
Humidity Settings.Experts say the ideal relative humidity in a home is between 30 and 50 percent -- below 30 percent is too dry and above 50 percent may leave you with a dust mite problem. A humidifier with an adjustable, built-in humidistat that regulates humidity levels and can be set at the level you prefer is one way to ensure that your home stays in the zone. An adjustable humidistat is not standard in low-cost humidifiers, however, and among those we researched only the Honeywell HCM-630 QuietCare, the Vornado HU1-0021-28 Whole-Room Evaporative Humidifier, and Holmes HM630-U Cool Mist Tower Humidifier boast this feature.
But all is not lost for frugal shoppers: in lieu of a built-in, adjustable humidistat, you can buy a humidity reader, like the Honeywell TM005X Wireless Indoor/Outdoor Thermo-Hygrometer (starting at $24). This handy accessory displays the temperature and relative humidity so you can adjust your humidifier accordingly. Moreover, good cheap humidifiers at least let you control the speed/output of the mist with a dial or settings of low, high, and sometimes, medium. Our top picks -- the Crane EE-5301 , Vicks Warm Mist V745A, and Honeywell HCM-630 QuietCare -- include adjustable mist settings.