An Uncomfortable, Too-Dry Indoor Environment Can Be "Cured" with a Humidifier

Most people think that humidifiers are only for the sick, bed-bound, or elderly. In reality, humidifiers serve many useful purposes, many of which have nothing to do with health! Can your indoor discomfort be "cured" by purchasing a humidifier?

When it's cold outdoors you may be shivering indoors even though the room is heated to 70° or more. You may notice that your nasal passages are dry, the furniture creeks, sparks fly, the piano goes flat and houseplants need almost constant watering. If so, blame these common problems not on the temperature but on the humidity - which is often lower in a heated home than in the Sahara Desert.

We all know that those who are in poor health benefit from the use of a humidifier, but what about the rest of us? Beside the typical medical uses of these machines, is there any other reason why you should install one in your home? You might be surprised to learn that these miracles of science are very beneficial for a number of reasons.

Reason #1: Humidifiers prevents dehydration

Most people recognize the discomfort of steamy summer time high humidity, but they may not realize that it's low humidity that makes them uncomfortable in heated rooms in winter. Dry air seeks moisture. It acts like a sponge, pulling water from any available source. When perspiration is evaporated to rapidly you feel chilled; with a low relative humidity it is necessary to heat the house to a higher temperature for comfort. Furthermore, the dry air soaks up the moisture normally present in the nose and throat, leaving the membranes dry and susceptible to infections.

Reason #2: Humidifiers prevent dry skin

Dry skin is another symptom of too-dry air. The women whose complexions are traditionally admired are those who live in damp climate, like England's, where central heating is not so common as in the United States and where the outdoor temperatures are not so low.

Reason #3: Humidifiers prevent damage to household goods

Besides the personal discomfort caused by dry air, there is apt to be damage to musical instruments, paintings, book bindings, other furnishings and the house itself as the moisture naturally present in wood and fabrics is pulled out. The static electricity that accumulates on carpets and clothing where there is no moisture in the air to carry it off causes of the electric shocks you get when you cross a rug and touch a light switch. It also accounts for the way a wool skirt clings to a nylon slip, and for the tendency of hair to become less manageable as you brush it.

How to determine if you need a humidifier

Before you rush off to the nearest hardware store, its important to determine if you need to add moisture to your indoor air. Likewise, you should gain a working knowledge of what humidity is, how it is lowered or increased, and how it is measured.

What is "relative humidity" and why is it often so uncomfortably low in a heated house? Relative humidity is as important a characteristic of air as its temperature. It is a measurement of water vapor actually in the air compared with the amount of water vapor that the air could hold at that temperature. It is expressed as a percentage. As the temperature increases, air can hold more water vapor. Cold air can hold very little moisture, so even if it is saturated, the actual amount of water vapor is low. When cold air is heated ( as it is when it comes into your house), the water vapor present in it is therefore only a small percentage of what the warmed air can hold. For example, suppose the outside air is 20° F. and the relative humidity is 75%. When the air is brought indoors and heated to 72° F., the relative humidity will drop to only 10%. Even in the dry Sahara Desert the average relative humidity is 25%!

You can determine the relative humidity of the air in your home with a humidity meter. An inexpensive one is accurate enough for most purposes. Most experts on temperature and humidity recommend a relative humidity between 30 and 50% for comfort and health. There are, however, some practical limits to how much you can safely increase the relative humidity, depending upon the construction of your house.

Common problems when using a humidifier

One of the most common problems that home owners encounter while using a humidifier is condensation on windows. Condensation forms on ordinary, single- sickness blast windows at much lower relative humidity than on storm windows or thermal glass. When the indoor temperature is 70° and the outdoor temperature is 0°, condensation appears on single glass windows at 16% relative humidity and double glass at 42%. At 20° outside, condensation forms at 28% relative humidity on a single pane and at 56% on double.

Condensation within the walls is the other problem to be considered. A house built within the last 20 or 25 years probably has a vapor barrier and insulation, so it should be able to handle all the humidity needs for comfort unless there is severe subzero weather. However, in an older house that has no vapor barrier, moisture can pass through the inside wall and condense when it hits the cold exterior wall, causing damage. Unless steps are taken to prevent this ( it's possible to seal cracks and paint the interior walls to form a vapor barrier), it's not advisable to raise the relative humidity to the 35% or so needed for comfort.

Getting a proper humidity level with a humidifier

The humidity levels recommended by health officials are based on a balance of the extremes of humidity permissible from a comfort standpoint only and the undesirable and potentially damaging effects of humidity that is too high. At lower outdoor temperatures it is generally desirable to maintain lower humidity within the home.

Assuming that the relative humidity can be raised to a satisfactory level without damage to the house, the question is how to do it. While there are a number of appliances designed to increase humidity indoors, many people choose not to use them for a number of personal reasons. On the other hand, makeshift measures for humidifiers are usually an adequate as well as in practical. Pans of water or wet towels on the radiators are unsightly and boiling water is a nuisance. A humidifier, permanently installed or portable, may be the best solution. If the house has been dry for a long time, there won't be much rise in the relative humidity for the first day or two that a humidifier is put into operation, until the dried out furnishings throughout the house have regained their normal moisture content.

Types of humidifiers

There are two basic types of humidifiers - evaporate or an atomizer. And evaporator humidifier may be a simple pan of water or a more complex model. One form, a hot-water vaporizer, heats water, picks up the vaporized air with a fan and puts it in the room. In another version, a surface evaporator, water is pumped from a reservoir to keep an evaporated surface continually moistened. There may be a fan to cool the air in and across this wet surface to speed the evaporating process, and the surface may be a washable filter that cleans the air as it is moved through the humidifier.

Evaporative humidifiers that operate without heat are not likely to over humidifier. As the humidity level goes up, the rate of evaporation slows down, and a natural balance of humidity in the air keeps the process from going too far. A humidistat is a useful tool, included with many evaporative humidifiers, can turn the motor off when the desired relative humidity is attained. With evaporative units any impurities such as minerals in hard water are left behind. If the unit is not cleaned regularly, the evaporating plates or filters can become clogged, making the unit less efficient.

Atomizing humidifiers release a fine spray of water into the air stream. They can provide a greater capacity than the surface units and it is possible to raise the relative humidity to the saturation point, so such units should have humidity measuring devices to turn them off automatically when the desired humidity is reached. Portable atomizing humidifiers are especially helpful in sick rooms. They are more expensive but safer than steam vaporizers. One disadvantage of atomizing humidifiers is that minerals in hard water are sprayed into the air and settle out as fine white dust.

Both evaporative and atomizer humidifiers are available for permanent installation and as portable or console models. Permanently install humidifiers can be connected to a water line for automatic filling or they can be filled manually. Portable table or console models need manual filling. Some have casters so that they can be wheeled to the kitchen sink. Many models have indicators to show when they need refilling, and many have humidity measuring devices

Sources:

http://www.jshumidifiers.com/the-importance-of-humidification-a-feature-in-modern-building-services-79-news/
http://www.allrightheatingandcooling.com/HVAC-articles/Humidifiers.html
http://www.all-about-humidifiers.com/humidifier-filters.html
http://hvac.networx.com/info/humidifiers/