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Humidify Your Home Without Problems

By Jason Earle Google+

Source: Habitat Quarterly

Life requires a delicate balance against the elements. Not too cold, not too hot. Not too moist, not too dry. Existence within those parameters makes for healthy living and comfort. Outside of them lies a breeding ground for conditions that often lead to illness and disease. It can be a matter of life and death.

Our bodies are 75% water. Our brains are up to 85%. All of our internal processes require robust hydration. A lack of water can cause numerous adverse health effects ranging from dry mucus membranes to nosebleeds and infections. In his book, The Body's Many Cries for Water, Dr. Batmanghelidj asserts: "Chronic, unintentional dehydration is the origin of most pain and degenerative diseases in the human body."

During the winter months - in cold climates - the humidity can drop to levels well below the human comfort zone. Air leaks allowing cold air into your home allow moisture be sucked right out of the building. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) suggests you maintain indoor relative humidity (RH) at 30-60%RH, but many people start experiencing some difficulties below 40%RH. In this case, adding moisture to the air is extremely important, but you must do it with a few things in mind, or else you'll end up with a different set of problems. Above 60%RH you start to create an environment potentially conducive to mold growth, dust mites, bacteria and other unwanted guests.

Here's the healthy home mantra: Don't modify what you don't quantify. Humidity gauges, also known at hygrometers, are inexpensive and give you the knowledge you need to decide whether or not you should add or remove moisture from your home. I like the Oregon Scientific RMR500ESA  because of the remote sensors, so you can monitor areas that are out of sight/out of mind, such as crawlspaces, attics, outbuildings, etc. I use one of these to keep an eye on the conditions in my kitchen, outside and the basement. The Extech Humidity Alert  is great for a standalone unit. It's inexpensive. I've only had to change the batteries once in 2 years. The screen is easy to read from a distance, but it does not have any remote sensor capabilities.

The next very important step is how you add humidity. This is where there's a lot of confusion.

Whole Home vs. Standalone

In essence you have to choose between the whole home systems, which are installed in the air handler of a forced air system, or standalone units, which you purchase retail and simply plug into the wall in whatever room you are most concerned with, which should be the areas where you spend the most time, especially your bedroom. My primary gripe with the whole home systems, also referred to as "inline," is that they used to malfunction terribly and were prone to microbial growth. The old drum types were the worst. Not only did they fail, but they also allowed every mold and bacteria on the planet to proliferate conveniently in the airflow of your ventilation system. If you have a humidifier built into your HVAC systems, have it evaluated by a professional to make sure you aren't pumping lots of other things into your ducts in addition to some much needed moisture.

Recently there have been some significant improvements in the way these inline systems are designed, which causes me less concern, but I still prefer the standalone units because they are easier to maintain and since they're visible, you're are more likely to do so.

Hot vs. Cool

There has long been a debate about the advantages and disadvantages of cool mist versus warm mist. Pediatricians have historically recommended cool mist over steam, primarily to reduce the chance of burns, which is rarely an issue today, with the units currently on the market. It's my professional opinion that warm mist and steam/vaporizer types are far better in terms of effectiveness and cleanliness.

Cool mist types utilize an evaporative wick and a fan. In essence water from a reservoir is forced to evaporate into the ambient air. These units are quiet and require little energy, but they are also the most likely to become veritable Petri dishes, fostering the growth of a wide range of microbes very similar to that of the whole home humidifiers I discussed above. Another advantage is they don't add heat to the room in which they're being operated. However, these units take a long time to bring the humidity up and require cleaning daily. When you're not using them, they should be emptied and dried thoroughly.

Also within this category are ultrasonic humidifiers, which utilize high frequency sound waves to cause a fine, cool fog to disperse from them. They are quiet and efficient, but often have the pesky side effect of creating a white dust, which can get all over your stuff. Some of them come with mineral absorption pads, which need to be replaced regularly, to help minimize this issue. Despite the fact that many of these units come with anti-microbial features, they still should be cleaned out daily. Like all humidifiers, when not in use they should be emptied and dried thoroughly.

Steamer/vaporizer types are very effective at increasing the humidity quickly but they add heat to the room and sometimes create a somewhat muggy atmosphere. It's always important to monitor the humidity to make sure you're in the safe zone of 40-60%RH, but especially with these. Many of them come with built in humidistats, so they turn off automatically when RH reaches the target setting. They don't need to be cleaned as often since the steam is such an effective antimicrobial, but you need to make sure not to leave the water in the reservoir for more than two days. Some people find that adding a tablespoon of 3% hydrogen peroxide or an ounce of colloidal silver does wonders to keep the water in the reservoir fresh.

Although they require more energy than the cool mist and ultrasonic units, it's still negligible, pulling about the same draw as a 40-watt light bulb. There are no issues with mineral dust being dispersed, but you will find mineral buildup inside the reservoir when you clean them. The big gripe I hear is that they can be a burn risk if you have little ones running around. In this case I would suggest you go with the warm mist type.

Warm mist units are the best of both worlds. They experience lower microbial activity than the cool mist variety and are very effective at adding moisture. Many of them have ultraviolet lights to help augment the antimicrobial nature of the hot water vapor, which is allowed to cool before leaving the unit, reducing the burn risk to almost zero. They do add some warmth to the room and can also create a muggy environment, especially if you let them run the humidity up above 60%, which is a big no-no.


Humidifiers require maintenance to avoid becoming breeding grounds for biological contaminants. Make sure you read the instructions and follow them. I highly recommended you steer away from using harsh chemicals such as bleach when cleaning your humidifier(s). You don't want that stuff being vaporized and the reactions with the plastic housing can cause other chemical compounds to occur which you wouldn't want to breathe.


My personal preference is the Enviracare Warm Mist Humidifier With UV Protection Model EWM-220. I have two of them running in my house, non-stop throughout the winter, and it makes a huge difference in my quality of life.

Humidity control is the most important aspect of healthy indoor air. Too little and you'll find yourself wrestling with constant colds, sinus issues and skin problems. Too much and you'll end up with an increased allergen load in the house due to dust mites and mold growth. If you follow the guidance above, you and your family should be in the clear and enjoy the wintertime just a little more.


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Humidify Your Home Without Problems
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