Humidifier buying guide

Humidifier buying guide

Anne, Painter, Cambridge

Guide written by:

Anne, Painter, Cambridge

35 guides

Humidifiers are used to regulate the humidity rate in rooms such as nurseries or spaces that have dried out through the use of radiators in the winter. Choose from a range of different types including evaporative cool mist, warm mist, ultrasonic and UV, and various options such as essential oil diffusion.

Important features

  • Cold mist
  • Hot mist
  • Ultrasonic
  • UV
  • Humidity rate and programming
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When and why to use a humidifier

Restoring healthy humidity levels

Serving the opposite function of dehumidifiers, humidifiers are designed – as their name suggests – to generate moisture in order to help restore optimum humidity levels indoors.
The average humidity rate generally ranges form 40% to 60%. However, when the heating is switched on over the winter, this rate can often fall to below 30%, which may result in a variety of health issues (chapped lips, sore throat, irritated eyes, sinusitis, respiratory problems, etc.). 
Humidifiers help to alleviate these symptoms by combatting the dry air and, in turn, improving both your comfort and quality of life.

Choosing a humidifier


When selecting a humidifier, pay special attention to the following: 

  • moisture capacity, based on room size;
  • the sound level, measured in dB;
  • operating life, depending on the size of the reservoir;
  • operating mode, either manual or automatic (via  a humidity sensor).   

It's worth noting that manufacturers' indiciations will note the maximum volume covered by the device.
There are a few different types of humidifier, each with its own strengths and weaknesses:

  • evaporative cool mist, the most common type;
  • warm mist, allows you to diffuse essential oils, helps to reduce germs and bacteria;
  • ultrasonic, the quietest type, emits liquid water vapour into the air;
  • UV, less common and more expensive but emits healthier water vapour. 

There is also a range of additional options for increased user comfort:

  • timer and programmer;
  • automatic empty reservoir turn-off;
  • essential oil diffusion for ultrasonic and warm mist humidifiers;
  • built-in light;
  • mister.

What are the different types of humidifier?

Evaporative cool mist humidifiers


Cold mist humidifiers work via natural evaporation and are equipped with a wick filter (or absorbent filter) to soak up the water. A fan is then used to blow a dry, continuous stream of air over the water-saturated filter in order to vaporisethe moisture.
The main drawback of this system is that it draws in any impurities in the water and then diffuses them throughout the room. As such, it is recommended to go for a model equipped with washable filters or to use antibacterial sticks. Using just 18W of energy on average, these devices are economical and generally used for domestic purposes.

Warm mist humidifiers


Warm mist humidifiers operate using a heating system that brings water to a boil and turns it into gentle, healthysteam. The boiled water is free frombacteria meaning that these models do not require any filters. However, be sure to pay attention to the water type. These devices work better with soft water; water with a high limescale content will quickly clog them up. They may also increase the room temperature slightly.
Warm mist humidifiers can also be filled with essentialoils – as long as you taking care to use the right amounts. This can, however, be dangerous around young children due to the risks of falls and burns. While these models much quieter than cool mist humidifiers – thanks to the lack of fan – they can, nevertheless, emits a rather unpleasant noise during the boiling cycle. As such, it's best to avoid using them in the bedroom.

Ultrasonic humidifiers


Ultrasonic humidifiers are the quietestmodels available. They are therefore particularly suited to use in baby rooms. High-frequency sound waves (which are almost inaudible) vibrate the metal diaphragm contained in the device. The water bursts and turns into microscopic droplets which are then propelled into the air by a fan.
This system has one small disadvantage: the minerals contained in water are also released into the air. It is therefore best to choose a humidifier with a descaling filter or to use distilled water to purify the air. Similarly, the humidifier should be cleaned regularly. These devices may also slightlydecrease the temperature of the room.

UV humidifiers


UV humidifiers use UV rays to destroy any bacteria present in the water. They come in both hotandcoolmist models and are particularly suitable for children or adults suffering from immuno-deficiency disorders.
The downside of these humidifiers is that UV lamps have a fairly short service life meaning they will have to be changed after just a few months of use.

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Humidifier features

Vapour density and humidification rate


The humidification rate is defined by the density of the water vapour
This rate will also depend on the volume of the room you want to humidify; the greater the volume, the higher the humidification rate must be. This is provided in cubic metres (m3).

Humidity rates

Humiditysettings allow you to set your desired level of humidity in specific rooms. Some automatic models have a humidity sensor which automatically stops and starts the device when it reaches your set humidity rate.

Operating life

The operating life of humidifiers is determined by the capacity of their reservoir; the greater the capacity, the longer the operating life. Most devices automatically go into standby mode when the reservoir is empty and feature a warning light that lights up when they need to be refilled.

Additional options for humidifiers


Depending on the model you go for, there may be a number of additional options available designed to improve user comfort:

  • timer and programmers used to programme different start times and mode cycles; 
  • ionising mode to neutralise odours;
  • anti-bacterial system to slow down bacteria growth;
  • digital display of water level;
  • LED warning light to indicate automatic stop in case of empty reservoir;
  • fans with two, three or four speed modes for different humidification rates;
  • control panel with digital display to adjust set humidity rates and fan speed;
  • essential oils for enhanced well-being.

Using and maintaining humidifiers

How to use a humidifier 

  • Place the humidifier in the middle of the room for better distribution of water vapour. Set it down on a flat and stable surface. 
  • Do not place your device on radiators or too close to the wall or curtains to avoid a build up of moisture.
  • After the first use, rinse the reservoir to eliminate any residue from the manufacturing processes.
  • If possible, used purified water to fill the reservoir.
  • Be sure to clean the device regularly in order to avoid bacteria build-up.

Please note: in addition to using a humidifier, don't forget to air out your rooms for around 10 minutes each day to renew the air in your house.

Caring for a humidifier

  1. Rinse the filter to remove any impurities.
  2. Wash the water reservoir. It is strongly recommended to use a specialist cleaning product to prevent the development of microbes.
  3. Wash the outside of the humidifier with a sponge.

Disinfecting a humidifier 

  1. Clean your humidifier on a regular basis.
  2. Fill the reservoir with a vinegar-based water solution (15% vinegar).
  3. Run the humidifier outdoors for an hour. 
  4. Rinse the reservoir and fill it with water.

Preventing bacteria growth

  1. Clean the humidifier every three days with a white vinegar solution.
  2. Clean and disinfect the device every two weeks

More information

Follow the links below for advice on related accessories and more helpful guides:

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Guide written by:

Anne, Painter, Cambridge, 35 guides

Anne, Painter, Cambridge

After 8 years of trade, I turned professional: I trained myself to be a painter and carpet layer either solo or with 16 years old comrades. 9 months later, following vocational school, my registration in Trades Directory, and the label ‘Artisan’ in hand, I created my company. And since then, I don’t even touch my brushes. I’m a self-taught DIYer and decoration enthusiast, I love to find and restore furniture and to create unique decoration elements. I completed the restoration of my sister’s house, this was last summer, with my niece: electrical, tiling, finishing, plasterboard...we did it all. And today, if I can share my experience I'm happy to do it. A total DIY enthusiast joke: ‘What’s the difference between a clown and a DIY enthusiast? A sense of humor.’ Good Luck.  

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