Why do you need room humidifiers?
Dry winter air helps cause chronic and recurrent upper respiratory infections. The nose and throat detest dryness! Their moist linings are excellent barriers against invasion by viruses and bacteria, but this protective function falters as these linings dry out. It is ideal to humidify all rooms, but all bedrooms should definitely be humidified.

What is the ideal relative humidity?
The nose and throat prefer a relative humidity of about 40-50% in the air we breathe. Humidity of less than 40% will lead to drying out of the nasal and throat linings while humidity of greater than 60% will facilitate the growth of molds and dust mites in the bedroom.

How can you measure relative humidity?
Determine the relative humidity with an inexpensive humidity gauge, technically known as a hygrometer. These are available as one unit in combination with a thermometer and are manufactured by the Springfield and Taylor companies. They are sold for less than $7 at hardware stores. Bionaire also produces an electronic humidity and temperature gauge, sold for approximately $30. It is likely more accurate and takes a measurement quickly, but it may or may not be worth the additional expense.

Taylor Temperature-Humidity Gauge

When should you turn on the humidifier?
When the outdoor temperature drops below 40°F during the day, night, or both, it is time to turn on the humidifier. As a rule of thumb, bedroom air will likely require humidification when the furnace is operating.

What is the best type of humidifier?
Five types of humidifiers are in common use today. These are the warm mist humidifier, the steam vaporizer, the evaporative humidifier, the cool mist humidifier, and the ultrasonic humidifier. The warm mist humidifier is a safe variant of the steam vaporizer. In both, the machine boils the water and only emits steam which is pure water vapor. Any bacteria or molds which contaminate the water in the reservoir will not be passed into the air and from there into your child’s throat or lungs. The warm mist humidifier is safer than the less expensive steam vaporizer because it mixes relatively cool room air with the hot water vapor before the machine emits it. The best warm mist humidifiers contain a fan to completely mix the room air with the steam and to distribute the blend around the bedroom more efficiently. Some recent warm mist humidifier models do not have an internal fan, and it is advisable to purchase a small portable fan to place near the vapor outlet in order to properly and safely mix the water vapor with room air. Warm mist humidifiers also contain a "humidistat", a device which turns the steam generator off once the humidity in the room reaches the desired level, which is 40-45%. Purchase a model which has a continuous humidity control rather than only a small number of settings such as low,medium, and high.

The less-desireable cold mist or ultrasonic humidifiers spray very tiny droplets of water from the reservoir into the air, and germs, including bacteria and molds growing in the water, travel in these microdroplets. Cool-mist and ultrasonic units also spray any chemicals or minerals present in the water into the room. This airborne debris then coats all walls and furnishings.

Cool-mist or ultrasonic humidifiers must be carefully cleaned on a daily basis, an impossible task for most of us. The evaporative types, usually console devices designed to be used in hallways, tend to readily develop mold on the wicks or belts, and these must be cleaned or changed frequently.

Steam-based humidifiers need not be cleaned as often or as carefully. The minerals and other chemicals which remain after the pure water vapor is boiled off must be rinsed out and sometimes scrubbed off the heating coils or plates.

Which units are currently on the market?
Consolidation has occurred in the humidifier manufacturing sector as in other others, and all common brands of humidifiers are manufactured by a company known as Kaz Industries. Current common brands are: Vicks, Honeywell, Holmes, Duracraft, and Enviracaire. I have reviewed the models available, and I am currently suggesting purchase of one of the following:

Vicks 790
This warm mist humidifier has UV lights, an added safety net, but likely redundant since the water boiling purifies it.

Buy Vicks online at:
http://www.amazon.com/Vicks-99-999-Germ-Free-Humidifier/dp/B001FWXJHS/ref=sr_1_1?ie=UTF8&s=electronics&qid=1252890646&sr=8-1


Honeywell HWM 500
Buy Honeywell online at:
http://www.amazon.com/Honeywell-HWM-500-Warm-Moisture-Humidifier/dp/B000U642TO/ref=sr_1_2?ie=UTF8&s=electronics&qid=1252891684&sr=1-2


Honeywell Enviracaire HWM 910
Buy Honeywell-Enviracaire online at:
http://www.amazon.com/HONEYWELL-ENVIRACAIRE-HWM910-Moisture-Humidifier/dp/B0000WM2J0/ref=sr_1_6?ie=UTF8&m=AP9TLT2LX6QXY&s=generic&qid=1252892033&sr=1-6


Enviracaire EWM 220
Buy Enviracaire online at:
http://www.amazon.com/Enviracare-Warm-Humidifier-Protection-EWM-220/dp/B000V73YY6/ref=sr_1_13?ie=UTF8&m=AP9TLT2LX6QXY&s=generic&qid=1252892033&sr=1-13

Buy Taylor Electronic Humidity Gauge - Indoor/Outdoor Thermometer on line at:
http://www.acehardware.com/product/index.jsp?productId=1279391&cp=&pg=2&searchSort=TRUE&sr=1&origkw=taylor&s=A-StorePrice-ACE&kw=taylor&parentPage=search&searchId=20797682523


Simple vaporizers
These are cheap ($20) simple boiling pots without fans or humidistats. If used in kids' rooms, they should be placed up on a table to avoid burns and placed in front of a good fan to spread the water vapor around. Cheap and reliable but messy.


© 2010 Howard G. Smith MD