Humidity and Moisture Levels in the Home

Moisture or "Water Vapour"
To put it simply, moisture (or water vapour) is water in a gas form (liquid being the obvious water, and solid being ice). One main way that water vapour increases is evaporation. Water evaporates everywhere; rivers, plants, the sea, lakes, puddles, the ground as well as just about any water source. The amount of moisture in the air can vary from a little to a lot, and the majority of the moisture contained within our atmosphere is in the initial ten thousand feet above the surface. Humidity is basically a measurement of the moisture/water vapour in the air.

Absolute Humidity
Absolute humidity is a measurement of the amount of moisture contained within the air, regardless of the temperature of the air. And is measured in grams of water vapour per cubic meter volume of air. The more moisture/water vapour in the air, the higher the level of absolute humidity.

Relative Humidity
Relative humidity also measures the amount of moisture in the air, but as a percentage relative to air temperature. Basically, its a measurement of the ACTUAL amount of moisture/water vapour currently in the air compared with the water vapour amount that can exist at the current temperature. It is simply a measurement as a percentage, telling you just how much of the air around you is water vapour, while being relative to the temperature. So 70% RH = 70% water vapour, 30% air.

Different relative humidity levels can suit different situations. The typical (and comfortable) humidity level suitable for home is around 50-55%. Mold will struggle to form and expand in anything under 50%, and it will be comfortable to live and breathe in.

There are situations where lowering the humidity will benefit though, such as Asthma sufferers. Dust mites and the debris that they leave behind are a common aggravator of those suffering from Asthma and they enjoy levels of 50% or higher. So lowering the level to around 40% will help control the mites and reduce the effects.

Another example is the condensation on windows that can occur in the winter months (or cold in general). A humidity of around 30% would help prevent this, all though some may find the air a little dry at this level.

So, heres a simple recap:

General "Right" Level: 50-55%

Dust Mite Prevention: 40%

For Asthma Sufferer's: 40%

Condensation in the Cold: 30%

The easiest way to do this would be use a humidity meter or otherwise known as a Hygrometer. If you dont own or want to have to purchase a hygrometer then the other way is to simply keep an eye out for symptoms of excess moisture. You can check out the symptoms of humidity and moisture damage HERE. If you do wish to purchase a hygrometer, then we recommend this one.

Many dehumidifiers for home feature humidistats and auto shut off features when they reach your required humidity. You could for example, have a basement that is at 70%, and you wish for it to go down to 40-50% and keep it at that, so you would programme your dehumidifiers for home to shut off once it reaches 40%, but maintain it at that and automatically bring it back down when needs be.

Or for the more simple and cheaper models which dont feature humidistats, you could assess your RH with a hygrometer (humidity meter) and just keep tabs on what level it is decreasing too.

If you need any more information, consumer advice or feedback on everything dehumidifiers (including product reviews), then why not come and visit us at Dehumidifiers for Home.com