- Indications for humidification in residential premises
- How a humidifier works
- Main characteristics of the equipment
- Choosing a humidifier before buying
- Impact on the human body and animals
Is it true that a humidifier is a complete salvation from dry air, or is there less attractive aspects of its use under the apparent benefits? We offer you to understand the features of operation, practical convenience and safety of popular household air humidifiers.
Indications for humidification in residential premises
The main reasons for the drying out of air in living quarters are mistakes in the choice of finishing materials, the organization of ventilation and heating. The problem is most acute in winter, when heating devices increase the temperature of the outside air, but the mass fraction of moisture remains unchanged. If we talk about relative humidity, then street air with a temperature of -5 ° C and a humidity of 90% when heated to a comfortable 24 ° C will already be considered dry – only 10% humidity.
Signs of insufficient air humidity are quite obvious. This is the drying out of the mucous membranes of the upper respiratory tract, eye irritation, feeling unwell, lethargy, loss of concentration and a permanent feeling of thirst. It is very easy to make sure that the humidity is low, just leave the moistened cloth anywhere in the room: it will dry “to a crunch” very quickly, literally in 20–30 minutes. However, it is better to purchase a simple electronic humidity meter with a thermometer, which will help to accurately monitor the state of the microclimate..
Children suffer most from dry air: their metabolism is active, and therefore, under normal conditions, heat exchange occurs faster than usual. The temperature produced by metabolic processes is dissipated mainly by the lungs along with the exhaled water vapor. If the air is dry, this process proceeds much faster than normal..
Insufficient moisture in the mucous membrane interferes with the functioning of the immune system, which increases the risk and complicates the course of respiratory diseases. This is a kind of scourge of modern pediatrics, but it is absolutely realistic to deal with the problem both with the simplest means and with the help of special household appliances..
How a humidifier works
Humidifiers are used to normalize air humidity. The principle of their operation may be different, respectively, the types of devices also differ. The main difference lies in the way the liquid is evaporated to water vapor..
Porous humidifiers are of the “cold” type. In them, active evaporation is due to the significant surface area of special “accordions” or sponges, which from time to time are automatically wetted with water. Air from the room is forced into the humidifier under pressure and passed through the porous material, facilitating the evaporation of the liquid.
Ultrasonic humidifier: 1 – ultrasonic head; 2 – water tank
The disadvantage of this technique is their low performance, which, moreover, depends on factors such as temperature and humidity at the inlet. The more humid the air in the room, the lower the efficiency of its additional humidification in the described way. However, this is often enough to maintain an optimal atmosphere. The main advantage of such humidifiers is the naturalness of the evaporation process. In addition, porous humidifiers also clean the air from dust and other suspended particles..
Nozzle and vibrating ultrasonic humidifiers do not evaporate water in the usual sense, but break it down into microscopic spray, carried away by the air flow. The main disadvantage of such devices is obvious: together with water particles, all the impurities they contain, from dissolved salts to microorganisms, enter the air. This is what justifies the opinion about the dangers of moisturizers for health. At the very least, they are very impractical: water settling on furniture forms a whitish coating that must be removed periodically, or purified (deionized) water must be used..
A spray humidifier is more often used not in individual household appliances, but in integrated air preparation units as part of microclimate systems.
Steam type evaporators use the most active principle of air saturation with water vapor. Boiling sterilizes water and evaporates in pure distilled form. There is also a downside: the heating element is subject to rapid wear when using poor quality water, besides, the electrical power of such devices is significantly higher than the rest.
Main characteristics of the equipment
In general, all humidifiers can be divided into devices that forcibly increase humidity, and evaporators that naturally restore its deficiency to a value of 50-60%.
Forced evaporation is used in ultrasonic (vibration), steam and nozzle devices. Since these humidifiers have the highest performance, it is imperative that they have a built-in hygrometer. Otherwise, air oversaturation with moisture is possible, up to the appearance of a dew point at room temperature and the formation of a real fog in the room..
The performance of a humidifier is determined by the volume of water that it can evaporate per unit of time and ranges from 200 to 500–700 ml / h. When choosing a humidifier, its performance should correspond to the volume of the room, the temperature and the intensity of air exchange in it..
For the calculation, it is necessary to determine the concepts of absolute and relative humidity. Absolute humidity is the actual mass of moisture in one cubic meter of air. The maximum water vapor content is determined by the temperature and for a comfortable 23 ° C is approximately 10 g per kilogram of dry air (density of dry air is approximately 1.20 kg / m33). With further saturation, an excess of moisture will fall out in the form of condensation.
A simplified i-d Mollier diagram displays the dependence of relative humidity on air temperature and the corresponding value of absolute humidity, expressed in grams of water vapor for each kilogram of dry air. The graph shows the areas corresponding to the optimal (blue outline) and acceptable (red outline) values of the parameters for residential premises
Relative humidity, namely, it is of key importance for humans, is defined as the percentage of the current mass of water in the air to the maximum possible at the current temperature. It would seem to raise the humidity from 30 to 60% in a room of 20 m3 only 100-120 ml of water needs to be evaporated. But do not forget about the working ventilation, which carries humidified air to the street and instead attracts cold air, which is again dried when heated.
Choosing a humidifier before buying
In hardware stores, most humidifiers are ultrasonic. Their cost increases along with the processed air volume, approximately 1000-1500 rubles for every 10 m3. There are few special differences in their device, the justification for the price above average is the design of the device and the use of long-lived components. The latter, however, is related to such eminent brands as Zanussi, Electrolux or Philips. Most of the Chinese equipment is distinguished by a typical device and at the same time high maintainability: a broken evaporator or cooler is easy to find an inexpensive replacement.
When choosing a humidifier, pay attention to parameters such as noise level and energy consumption. A significant advantage can be an increased volume of the container, so the humidifier will have to be filled with water less often. All kinds of electronic gadgets such as preset operating modes or an indicator panel do not play a decisive role, just a humidity regulator is enough, which will turn off the evaporator when the set value is reached, and control of the tank filling.
Much less often you can find steam and porous humidifiers, their cost is on average 20-30% higher than that of more or less high-quality ultrasonic humidifiers. If you have the opportunity, it is advisable to purchase exactly these types of appliances, especially if they will be used in bedrooms and children’s.
If you want to solve the problem with your own hands, there are detailed instructions on how to independently assemble a high-performance humidifier from inexpensive and affordable spare parts.
Impact on the human body and animals
Air saturated with moisture has no less destructive effect than dry air. Humidification of the air by spraying finely dispersed water rather than evaporating is too superficial an approach to the problem. We have already said that together with moisture droplets, in this case, all the impurities contained both in the source water and in the air blown by the built-in fan of the device are distributed. An ultrasonic humidifier can at least cause an immediate spread of respiratory disease to all family members, although only one of them is sick.
Vibration and spray humidifiers can also cause a number of diseases, from simple bronchitis and respiratory irritation to pneumonia, pneumonia and even exotic infections such as legionellosis. The opinions of most therapists and pediatricians agree on this..
In living quarters, it is better to use humidifiers of natural evaporation type – porous or steam. They help to increase the humidity to normal comfortable values, while porous humidifiers cannot saturate the air with vapors in excess, therefore they often do not have regulators.
Pay particular attention to the so-called air washers. Together with moisture, they absorb airborne dust, spores and pollen, which is extremely important for chronic allergy sufferers. If it is not possible to purchase such a humidifier, take care of at least using high-quality (purified and disinfected) water or choose a device with built-in liquid and air filters. As one of the options, you can offer the treatment of the water used with silver ions or liquid antiseptics..