A filter is used on some humidifiers to absorb the water from the reservoir and release into the air. It also acts as a filter sucking all the harmful particles and minerals out of the air and water.

Humidifiers with no filter use a much less complex system to clean the water, electricity heats the water to a steam that is released. These humidifiers with no filter are steam humidifiers, or vaporizers.

A benefit of steam humidifiers is how closely you control the level of humidity. The temperature of the heat is dependent on the temperature of the room.

Many people buy these humidifiers to help relieve cold, flu and sinus symptoms. Often medicine is added to the water in the base to intensify the relief.

There are two important problems to acknowledge with humidifiers with no filter. These units need to be placed out of the reach of children. The steam that exits the unit is extremely hot and can easily burn a child. Because the machine uses electricity to generate heat, it also can become very hot. Do not leave it on the floor or upholstery because it can be a fire hazard.

Despite these problems, a humidifier with no filter is one of the most economical humidifiers. The unit itself is often inexpensive. Unlike other types of humidifiers, tap water can be used in the tank. The minerals that may be harmful are boiled out. Beyond that you do not have to purchase filters to change every few months. However, this unit uses more electricity than an evaporative humidifier. On average a humidifier with no filter that releases 350g of water will use 325 watts of energy, but an evaporative model would use only 10-20 watts. A humidifier with no filter uses more energy because it heats the water with electricity before release.

Maintenance on humidifiers with no filters is extremely simply. Empty the tank of water then add lime scale remover and a small amount of water, and let it sit for a few minutes. Rinse the cleansers out and wipe the unit dry and then it is ready for use.