Which Humidifier?

Steam Humidifier? Ultrasonic Humidifier? Evaporative Humidifier or Air Wash? Let us help you decide.

We sell four different types of humidifier, which are steam humidifiers, ultrasonic humidifiers, evaporative humidifiers and air washers. Your choice will depend on your application, budget and acceptable level of maintenance.

Humidifiers are needed for many reasons…

To help people – Humidifiers will help to relieve respiratory illnesses in adults and croup in babies, they can stop dry eyes, dry skin and dry throat conditions, help relieve asthma and allergy symptoms, they can also stop feelings of tiredness, in fact humidifiers are often put into offices to improve the productivity and reduce absenteeism.

To protect objects – Humidifiers will protect valuable art, furniture and musical instruments from the effects of too low humidity or varying humidity levels which can cause wood and paper to expand and contract which can cause splits, they will also help musical instrument such as pianos and harps to stay in tune. Humidifiers are often used in office buildings to reduce static which can damage computers and servers.

Humidifiers increase water content in the air by either boiling water and thereby creating steam which is absorbed into the air, or by releasing very fine wisps of moisture by breaking up water molecules by vibrating crystals at a specific frequency (Ultrasonic) or by passing air through a wetted filter so that the the air picks up water through the moistened surface.

Here is a guide to help you choose which humidifier my suit your application.

Steam humidifiers

Steam humidifiers provide hygienic humidity control as the process of heating water to steaming point kills all bacteria and germs so that the moisture released is sterile.

In the home a steam humidifier is the ideal choice for anyone with a respiratory illness, for ensuring there is sufficient humidity in a nursery or for combating the symptoms of croup in babies. The steam humidifier can be used in conjunction with essential oils. Steam humidifiers are very quiet.

This type of humidifier is usually economical to buy in comparison with other humidifiers. Units that incorporate a humidistat can cost a bit more but have the advantage of not over-humidifying a room.

A disadvantage of using a steam humidifier is that they consume more electrical energy than an ultrasonic or evaporative humidifier.

The maintenance of a steam humidifier will involve occasionally removing the lime scale that builds up inside the unit. When not in use steam humidifiers should be emptied of water, cleaned and dried to prevent water stagnating inside the humidifier.

Steam humidifiers such as Carel as commonly used in office buildings to reduce static and make the air more comfortable to breathe, usually they are installed into the air conditioning ductwork, although more expensive to run than the other two types, they have the advantage due to the exceptional control and for hygiene reasons

Ultrasonic humidifiers

This is the most common type of humidifier you will find in the high street. An ultrasonic humidifier has a reservoir of water on top of a small metal plate coated in very small crystals, when a level of 48 Volts is passed through the crystals they begin to vibrate, the intense vibrations caused by the rapidly oscillating plate atomises the water into an airborne mist.

The advantages of buying an ultrasonic humidifier is that as well as being economical to buy they also consume little energy when operating. The vapour produced is very fine, almost cloudlike. Ultrasonic humidifiers are extremely quiet.

The major disadvantage of using an ultrasonic humidifier is the dust that it introduces to a room. Any particulate matter that is present in the water will become airborne along with the water. When the water evaporates, the particulate matter will settle as dust in the room.

However, high quality ultrasonic humidifiers use demineralisation cartridges that absorb the minerals from the water prior to it being turned into a mist. This is very effective as long as the cartridges are replaced inline with the manufacturer’s instructions.

If your humidifier does not include a demineralisation cartridge then you should use demineralised water, as over time the mineral content of the water will coat the ultrasonic crystals which stops them working.

It is very important to clean your humidifier out regularly when is use to prevent the build up of bacteria.

Evaporative humidifiers

Evaporative humidifiers get water into the air by allowing moisture to be simply evaporated. This consumes very little energy and is a hygienic way of humidifying as there are no aerosol sprays being released. Any particulate matter present in the water will remain in the humidifier after the water evaporates so no dust is released into the room.

This type of system is also very quiet so can be used in a bedroom or similar quiet area.

Evaporative humidifiers use porous filter media which adsorbs water and the air is forced through the filter by a fan, as the air flows through the wet filter media it picks up water and becomes optimally humidified. You cannot over humidify a room with this method, as the humidity gets closer to 50%rH the air will collect less and less water.

This is the best type of humidifier to use to protect artworks, furniture and musical instruments, this is often the type museums will buy to protect their exhibits.

The main disadvantage with this type of unit is that the filters need to be cleaned or replaced regularly. The air in a home can be quite polluted with dust, skin, hair and other matter. These particles will be collected by the humidifier and remain on the filter as the air passes through. This has the advantage of cleaning the air but does mean the filters need replacing occasionally they may develop an odour and become unhygienic.

Cleaning will need to be carried out regularly to maintain hygienic operation but the frequency will depend on the air quality in the room. Radiator humidifier  also come under the heading of evapoartive humidifiers but these release vapor from a pad by heating it from your radiator.


These humidifiers work in the same way as evaporative humidifiers but instead of an evaporative mat they have disks which revolve trappinmg water between them, air is passed through and picks up humidity, the advantage of these is that they cannot over humidify as the air will not pick up extra humidity after it reaches 50% rh, also there is a massive saving on spare parts and the discs do not not need to be replaced and they can be put through a dishwasher to clean, the humidifier also works as an air filter which is very heathy.