A humidifier is a household appliance that increases humidity (moisture) in a single room or in the entire home. There are point-of-use humidifiers, which are commonly used to humidify a single room, and whole-house or furnace humidifiers, which connect to a home's HVAC system to provide humidity to the entire house.
Evaporative humidifiers
The most common humidifier, an "evaporative", "cool mist", or "wick humidifier", consists of just a few basic parts: a reservoir , wick and fan .
The wick is a filter that absorbs water from the reservoir and provides a larger surface area for it to evaporate from. The fan is adjacent to the wick and blows air onto the wick to aid in the evaporation of the water. Evaporation from the wick is dependent on relative humidity. A room with low humidity will have a higher evaporation rate compared to a room with high humidity. Therefore, this type of humidifier is self-regulating: As the humidity of the room increases, the water vapor output naturally decreases. These wicks become moldy if they are not dried out completely between fillings, and become filled with mineral deposits over time. They regularly need rinsing or replacement—if this does not happen, air cannot pass through them, and the humidifier stops humidifying the area it is in and the water in the tank remains at the same level.
Other types of humidifiers
Other types of humidifiers include:
- Vaporizer (Steam Humidifier) (Warm Mist Humidifier) — Boils water, releasing steam and moisture into the air. A medicated inhalant can also be added to the steam vapor to help reduce coughs. Vaporizers may be more healthful than cool mist types of humidifiers because steam is less likely to convey mineral impurities or microorganisms from the standing water in the reservoir. Boiling water requires significantly more energy than other techniques. The heat source in poorly-designed humidifiers can overheat, causing the product to melt, leak, and start fires.
- Impeller Humidifier (Cool Mist Humidifier) — A rotating disc flings water at a diffuser, which breaks the water into fine droplets that float into the air.
- Ultrasonic Humidifier — A metal diaphragm vibrating at an ultrasonic frequency creates water droplets that silently exit the humidifier in the form of a cool fog. Unlike the humidifiers that boil water, these water droplets contain any impurities that are in the reservoir, including minerals from hard water (which then forms a white dust on nearby objects), and pathogens growing in the stagnant tank. Ultrasonic Humidifiers should be cleaned regularly to avoid bacterial contamination which may be projected into the air.
- hydro-pneumatic capillary system Humidifier (Non Electric Humidifier) A water powered technology that uses no electricity at all to power the unit. Advanced valve and capillary system.
Impeller and ultrasonic humidifiers do not selectively put water in the air, they also add any suspended material in the water to the air such as microorganisms and minerals. The amount of minerals and other materials can be greatly reduced by using distilled water, though no water is absolutely pure. Filters may also reduce the amount of material but the EPA warns, "the ability of these devices to remove minerals may vary widely." Depending on the volume, this dust may have negative health effects. Wick humidifiers trap the mineral deposits in the wick; vaporizer types tend to collect minerals on or around the heating element and require regular cleaning with vinegar or citric acid to control buildup.
Forced-Air Humidifiers (whole-house)
For buildings with a forced-air furnace, a humidifier may be installed into the furnace. They can also protect wooden objects, antiques and other furnishings which may be sensitive to damage from overly dry air. In colder months, they may provide substantial energy savings, since as humidity increases, occupants feel warm at a lower temperature. Bypass humidifiers are connected between the heated and cold air return ducts, using the pressure difference between these ducts to cause some heated air to make a bypass through the humidifier and return to the furnace. The humidifier should usually be disabled during the summer months if air conditioning is used; air conditioners partially function by reducing indoor humidity. Common styles:
- Drum style (bypass): A pipe brings water directly to a reservoir (a pan) attached to the furnace. The water level in the pan is controlled by a float valve, similar to a small toilet tank float. The wick is typically a foam pad mounted on a drum and attached to a small motor; hot air enters the drum at one end and is forced to leave through the sides of the drum. When the hygrostat calls for humidity, the motor is turned on causing the drum to rotate slowly through the pan of water and preventing the foam pad from drying out.
For the latter reason especially, drum-style humidifiers should always be turned off at the water supply during summer (air conditioning) months, and should always be used with high quality furnace air filters (MERV ratings as high as possible to ensure small numbers of mold spores reaching the humidifier's pan) when the water supply is turned on.
- Disc Wheel Style (bypass): Very similar in design to the drum style humidifiers, this type of furnace humidifier replaces the foam drum with a number of plastic discs with small grooves on both sides. This allows for a very large evaporative surface area, without requiring a great deal of space. Unlike the drum style humidifiers, the disc wheel does not need replacing.
- Bypass Flow-Through Style (bypass - also known as "biscuit style" or many other, similar variant names): A pipe brings water directly to an electrically-controlled valve at the top of the humidifier. Air passes through an aluminum "biscuit" (often called a pad; using the term "biscuit" to emphasize the solid rather than foamy form) which is similar to a piece of extremely coarse steel wool. The biscuit has a coating of a matte ceramic, resulting in an extremely large surface area within a small space. When the hygrostat calls for humidity, the valve is opened and causes a spray of water onto the biscuit. Hot air is passed through the biscuit, causing the water to evaporate from the pad and be carried into the building.
- Spray Mist Type : A pipe, usually a small plastic tube, brings water directly to an electrically-controlled valve in the humidifier. Water mist is sprayed directly into the supply air, and the mist is carried into the premises by the air flow.
- Additional types : 'Non-Bypass Flow-Through' (fan augmented), 'Steam', 'Impeller or Centrifugal Atomizer' and 'Under Duct'.
Disadvantages and risks
If the relative humidity is over 60% vol, then the use of a humidifier can allow the reproduction of dust mites or the growth of harmful mold, which can be especially harmful for children and the elderly. The relative humidity should be kept between 40% and 60%. Can also cause Hypersensitivity pneumonitis (humidifier lung).
Some humidifiers now use Microban technology to reduce mold and bacteria growth within the humidifier.
The EPA provides detailed information of the risks as well as recommended maintenance procedures. If the tap water contains a lot of minerals, also known as hard water, then the ultrasonic or impeller humidifiers will produce a "white dust" (calcium is the most common mineral in tap water), which usually spreads over furniture, and is attracted to static electricity generating devices such as CRT monitors. The white dust can usually be prevented by using distilled water and a demineralization cartridge in ultrasonic humidifiers.
See also
- Dehumidifier
- Flower robot
- Humidity
- HVAC
- Hygrometer, for measuring humidity
- Ioniser
- Misting fan
References
- ^ a b c "Indoor Air Facts No. 8: Use and Care of Home Humidifiers". Environmental Protection Agency. 1991 . http://www.epa.gov/iaq/pubs/humidif.html .
- ^ http://www.cpsc.gov/cpscpub/prerel/prhtml06/06215.html
- ^ "The Inside Story: A Guide to Indoor Air Quality". Consumer Product Safety Commission . http://www.cpsc.gov/cpscpub/pubs/450.html .
- ^
Whole House Water Filtration Systems | Home Filter ...
Of all companies offering whole house water filter ... Whole House Water Filtration Systems | Home Filter System ... for households that are on well water ...
Aquasana Whole House Filter Systems by Aquasana Water ...
Rhino EQ-300-85 Whole House Well Water Filter. The Rhino EQ-300-85 Whole House Well Water Filter System is designed for well water issues. In addition to removing everything else ...
SimplyPure Whole House Water Filter System | FAQ
SimplyPure Whole House Water Filter System by InnerLight ... Q5: How is SimplyPure™ installed if I have well water? SimplyPure™ would be ...
Water Filters: Reverse Osmosis Systems, Water Softeners ...
Water Filters, Reverse Osmosis Systems, Kitchen Faucets & Whole House Water Filtration. ... osmosis systems offered here as well ...
Whole-House Water Filters | Best Whole House Water ...
... water supplies can contain harmful or toxic contaminants as well. Whole house water ... Whole-House Water Filter System by Aquasana. The water filter rated best by the Allergy Buyers ...
PuriTeam | Whole House Water Filtration System | Water ...
... and Whole House Water Filters. You ... for my whole house water filter system ... separate water filter systems (a BB20 and a WHX-51). I have moved the WHX-51 to a second house as well
UV Water Purification : Commercial Water Softener ...
Absolute Water System will help you find the best UV water purification, commercial water softener systems, whole house well iron and residential water filters.
Crystal Quest Whole House Water Filtration System ...
... Water for Whole House Water Filter ... Well Water Filters. Crystal Quest has ... or CRYSTAL QUEST water filtration system: drinking water filter, shower and bath filter, whole house ...
PuriTeam | Whole House Water Filtration | Whole House ...
Whole house water filtration systems filter all the water in ... whole house water filter will make in your home. For well water ... parts for my whole house water filter system from ...
Whole water filter systems, under sink and whole house ...
... house water filter cartridges and whole house water ... 12 or 14 GPM system, or higher, depending on the number people in the home and the number of bathrooms. Common Well Water ...