Common dry air symptoms are dry skin, itchy eyes, sore throat and a stuffy nose. Common nuisances such as increased static electricity, peeling wallpaper, and cracks in paint and furniture can be noticed as well.

Instruments that measure relative humidity levels in percentage (% RH) are called hygrometers. Humidity levels range from 0% to 100%. A comfortable humidity level is 40-50%. Usually in the winter time the humidity level drops below the recommended level.

Most people are comfortable with a humidity level of 40-60%. Humidity levels above 60% can leave water marks on the walls and furniture. You can use a hygrometer if you would like to know what the specific humidity level in your room is. Some humidifiers are equipped with a humidistat function that allows you to set the desired humidity level.

A humidistat is a special feature that allows you to choose the desired humidity level that should be maintained throughout the day. Humidifiers with this special intelligent feature calculate the humidity level in the room and only add the necessary amount of moisture to the air to reach the desired level of humidity. The unit will thus cycle on and off to maintain this level. High-end humidifiers are equipped with this feature. Other humidifiers (evaporative units) ensure that a balanced humidity level is maintained naturally, but they do not allow you to choose the desired humidity level.

Evaporative humidifiers follow the laws of physics. They automatically provide a balanced humidity level. This is known as the ‘self-regulating’ principle. Due to the laws of physics, the air will only accept the amount of moisture it is able to hold at a particular temperature. The air cannot therefore become too moist.

Ultrasonic: An ultrasonic humidifier uses a metal diaphragm vibrating at an ultrasonic frequency to create water droplets that are released into the room.

Warm steam/vaporisers: A warm steam humidifier has a heating element that boils the water to produce steam. A vaporiser is a very simple unit that has two carbon electrodes. Electricity passes between the electrodes and vaporises the water while doing so, producing steam.

Cool moisture (evaporative): A cool moisture humidifier works through the process of evaporation sped up by the use of a fan and filter. The filter pad “wicks”, or soaks, up the water from the humidifier base. A fan blows air over a filter pad causing the water to evaporate from the pad into the air.

Ultrasonic: Some ultrasonic humidifiers are equipped with a cartridge that removes minerals from the water; their usage is recommended in hard water areas. A demineralisation cartridge will help avoid the accumulation of minerals in the appliance and their release into the air (the minerals form a white dust that can sometimes be noticed around the appliance).

Warm steam/vaporiser: No filter is usually required.

Cool moisture (evaporative): Wicking filters are required for cool moisture (evaporative) humidifiers to function. A cool moisture humidifier operated without the filter does not produce any moisture. We recommend always using filters in units that call for them.

Caution should be taken when using a warm steam or vaporiser unit around a child because the unit boils small amounts of water. Children should never be left unattended around the humidifier.

Warm steam/vaporizer: These types of humidifiers remove up to 96% of bacteria during the boiling process. Any bacteria or algae present in the water will be killed by the high water temperature.

Cool moisture (evaporative): The filter pad traps mould, bacteria, algae and minerals in the water. The filter pad is treated with antimicrobials to help prevent the growth of such microorganisns. Since the water enters the air by through evaporation from the filter pad, any impurities will be left behind in the pad and will not be released into the air.

The unit should be rinsed daily and thoroughly cleaned weekly (following the instructions in the manual). The unit should also be emptied if not in use and the filter should be dried (if applicable).

Germ-free technology ensures that only pure mist is released, by killing the water-bred germs. The water from the tank is scanned by the UV light before being released into the air. Up to 99.9% of the germs contained in the water are thus killed. This patented technology works in a similar way to the sun’s UVC rays that inhibit the growth and reproduction of dust mites, bacteria, viruses, fungi and moulds.

Running time: corresponds to the time that the unit can run on a single filling. The longer the running time, the less intervention is required from you.

Room size suitability: in order to ensure efficient humidification, check that the product room size capacity is greater than or equal to the area in which you want to use the product.

Wattage: if you plan to use a humidifier for a long period of time, it is important to choose one that has low power consumption, like evaporative and ultrasonic humidifiers. To determine the cost to operate the unit, divide the wattage (e.g. 25 watts) by .001 and multiply this by your cost per kilowatt hour. This gives you the cost per hour to run the machine.

Warm steam humidifiers have a fragrance cup that can be filled with essential oils. The steam produced by the humidifier will activate the essential oils.

Vicks has innovated with its VapoPads® heater, which now allows all humidifier types to release menthol scents in the room. Adding menthol treatments to your moisturising efforts will not only bring back that special aroma from your own childhood, but it can also help relieve congestion and cold symptoms.

Vicks humidifiers have a two-year limited warranty.