Using an essential oil diffuser to humidify the air: good idea?

What do we mean by “air humidity” or “humidity level”? Scientifically, we speak of relative humidity rate (φ), which represents the quantity of water actually present in the air in relation to the maximum quantity of water that the air can “contain” at a given temperature (what is called the saturation vapor pressure beyond in which the water becomes liquid again, resulting in rain or mist). This rate depends on the temperature. At 20°C, the Pvap is 17.3 g of water/m3 of air. A relative humidity of 50% therefore means that there is 17.3/2=8.65 g of water/m3 of air.

In a home, it is usually recommended to maintain relative humidity between 40 and 60%. However, it is not uncommon that in winter, when you heat your home, the relative humidity drops to below 30%. Too dry air can promote the appearance of certain diseases, mainly ENT (colds, bronchitis, etc.). To limit this, it is therefore necessary to increase this humidity level, and for that, there are not 300 solutions. : you have to add water (well, water vapor) to the air.

Let's take the example of a room of 10 m² (i.e. a volume of approximately 25m3). At 20°C, to increase the relative humidity by 1%, you must add 17.3/100*25=4.325 g of water to the air. To go from 30 to 40%, you will therefore need to add 43.25 g or 43.25 mL of water.

The simplest (and often most effective) method is to boil water in the room: the water turns into steam and the relative humidity increases. Unfortunately, it is not always very practical (nor very prudent) to install a gas stove and a pan of boiling water in the children's bedroom!

This is why there are humidifiers, which work in the same way as mist diffusers (a membrane sends ultrasound into a water tank, creating a mist that spreads into the air). This is why you will sometimes hear that a mist diffuser can be used as an air humidifier. logical you might say, well no, because we are omitting a small detail: the power (again!) of the machine:

A mist diffuser such as those that we offer on our site will diffuse approximately 10 mL of water in 1 hour: if we return to our example of a 10 m² room, this would theoretically increase the humidity of our room by approximately 2%. It's a bit weak, isn't it? What if you let the diffuser run longer? (its tank is 100 mL after all, and we only need 43 mL to reach our 40%!). Here again, theoretically this is correct, but in practice, the diffuser will not send the water throughout the room, the water, in the form of mist (micro droplets) and not of vapor (gas), will not stay suspended in the air for very long, and therefore the humidity will not increase.

To compare, an ultrasonic air humidifier can project between 180 and 250 mL of water into the air per hour, or 20 times more than our diffusers. Enough to modify the humidity level much more effectively!

In conclusion, to humidify the air, you need a humidifier (or a pan) but to diffuse essential oils, you need a diffuser! Easy to remember, right?