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How to Buy a Dehumidifier

Who needs a humidifier? Anyone who has uncomfortably dry or itchy eyes, throat or skin, or whose asthma is a problem indoors during the heating season. In addition to the health benefits, a humidifier can also reduce static electricity, peeling wallpaper, and cracks in paint and furniture. Consumer Reports

Getting started - Humidifier guide
Ideally, indoor humidity should be 30 to 50 percent. But without humidification, that level can drop to 10 percent in winter, because cold air holds less moisture and dries even more as it¿s heated.
Today’s humidifiers have improved over some earlier models, which spewed white dust in our tests. But tabletop and console models still require frequent maintenance. Minerals in tap water can cause an accumulation of scale, a breeding ground for bacteria. Parts of the humidifier need to be descaled regularly with vinegar and disinfected with bleach, and filters and wicks require periodic replacement. Note, too, that hard water might reduce some humidifiers¿ output and increase buildup of scale.

If you’re not ready to commit to regular maintenance-and if your home has forced-air heat-consider an in-duct humidifier that’s plumbed into the water supply and drainpipes. Such units don’t need refilling, and their easy-change filter requires service only once or twice a year.

Types of humidifiers
Choosing among the three major types of humidifiers-tabletop, console, and in duct-involves trade-offs in efficiency, noise, and convenience. Primary considerations include the size of the space you need to humidify and how much you’re willing to spend.

Tabletop humidifiers
These portable models cost the least and are fine for humidifying a single room, but their small tank requires frequent refills. Evaporative tabletops use a fan to blow air over a wet wick, while warm-mist models use a heating unit to boil water before cooling the steam. Evaporative models are much cheaper to run, but their fan is noisy.

Console humidifiers
Although console models are larger than tabletops, they can still be moved from room to room. Their large, powerful fan blows a strong air stream across water, generating lots of moist air. Since a console can humidify more than one room, it allows more options for unobtrusive placement wherever an electric outlet is available. A console’s larger tank needs less frequent refills, but it’s more cumbersome to handle. All console models use evaporative technology, which is noisy. If noise is an issue, run your console for several hours until bedtime and then turn it off, or use two or more warm-mist portable models.

In-duct humidifiers
These humidifiers are the ideal choice if you have a forced-air heating system and want to humidify the whole house. They tap into the air ducts and are plumbed into the water supply. Most are evaporative-bypass units, which blow air over a wet wick. Some emit a warm mist. Others are nebulizers, which use a spray technology-and which may produce deposits of white dust from minerals in the water. In-duct humidifiers are quiet and require minimal maintenance. They’re also the least expensive to run: about $30 or so per year, compared with as much as $350 or more for four tabletop models. But they generally require professional installation.

Humidifier features
Choosing a humidifier involves trade-offs among efficiency, cost, noise, and convenience. Our tests also show that you can’t tell how well a humidifier will work based on claims. Here are the humidifier features to consider.

Ease of use
A tabletop or console humidifier should be easy to move and clean. The tank should fit easily beneath your faucet. (Some consoles have no tank. You need to fill them directly.) On evaporative models, the wick should be easy to replace. Look for user-friendly digital controls and displays of humidity level and settings.

Most humidifiers have a dial or digital humidistat that shuts off the unit when it reaches a preset humidity level. Models without a humidistat can raise the humidity enough to cause condensation on windows. Also, too much humidification can promote growth of mold, bacteria, and dust mites. Be aware that most humidifiers won’t let you set the humidity below 30 percent, a level that can cause window condensation when outside temperatures drop below 20° F. That means you might not be able to use the humidifier when the weather turns very cold.

Some warm-mist tabletop models make little or no noise beyond mild boiling and hissing sounds. But comparably sized evaporative models we tested emitted 45 to 50 decibels on their low setting and even more on their high setting. For large areas, consider buying a console model and placing it away from sleeping areas. You’ll spend less than you would on several warm-mist tabletop models, and the water vapor will travel quickly enough to benefit remote bedrooms if doors remain open.

You can program some tabletop and console models to turn on at a set time so that your room is at the right humidity when you get home. But this convenience might pose a problem: Water that sits in the tank for hours can breed microbes if you don’t dry the humidifier thoroughly between uses.

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