Convection is one of the many heating methods available on the market. Yet, what is convection and how do convection units work exactly?
Convection results from heating the air by placing it in contact with a heating element. A totally natural and silent method, convection is governed by some physical principles that must be understood to grasp the operation of different convection heaters and make the right choice.
The first principle is that of air movement according to its temperature. Indeed, warm air rises while cold air tends to descend. Think of hot air balloons. These rise when the burner heats the air in the balloon. When the air gets colder, the balloon goes down. In the same fashion, when your heater warms the air in the room, the air tends to rise towards the ceiling. Once this is done, the next objective for the unit is to effectively deflect that rising hot air stream so that it can move toward the center of the room. Otherwise, it will run along the wall and stay concentrated on the ceiling which nobody wants.
The second principle of physics you should know about is that by warming the air, it lightens and takes more and more speed. It is therefore important for the heater to use this acceleration movement as a catalyst to better direct the airflow towards the center of the room (and not the ceiling). The greater the vertical distance between the heating element and the air outlet, the greater the heater’s ability to improve the acceleration of hot air. This is commonly known as the "chimney effect".
Types of convection units
There are two major families of electric convection appliances with their own advantages and disadvantages.
The first family is that of electric baseboard heaters. Electric baseboards are very low-level heaters that are installed close to the ground. The advantage of these units is their purchase cost and size. Indeed, since they are low, it allows installing them under windows or other places lacking space height. Nevertheless, this size conceals a major disadvantage. Since they are so low and open on the facade, they are therefore not very efficient at improving the acceleration of hot air particles and directing the airflow towards the center of the room. Indeed, as you see in the image below (left section of the image) the air runs along the wall and then remains stagnate at the ceiling. This concentration results in a significant stratification of the air in the room. In addition, baseboards are, according to their wattages, also very wide, which sometimes limits their installation.
The second family is that of the electrical convectors (right section of the image). Typically, these heaters have a greater distance between the location of the heating element and that of the air outlet than baseboards have. As we have seen, since they have a greater distance between the air outlet and the heating element, this allows them to improve the "chimney effect". Moreover, the orientation of the hot air outlet also allows better redirecting of the hot air towards the center of the room. Finally, the fully covered front panel of the convectors improves the chimney effect by trapping inside the casing thus improving its speed. Several affordable convectors exist on the market including the Apéro from Convectair.
Visualize the effect of a good heat distribution in real time by watching this video!
Improve the convection effect in the room
As we have seen, there are several elements that make a heater improve the convection effect and heat distribution within a room. We have summarised them here:
The chimney effect: As explained, the higher the height of the appliance and the greater the distance between the heating element and the air outlet, the better the chimney effect. This allows the heater to better distribute hot air in the room. If your unit is too low, such as electric baseboards, it will not be able to easily accelerate and redirect the air both of which are necessary for good heat distribution. It will only hug the wall and concentrate at the ceiling. The impact on the comfort level is significant.
Hot air redirection: It is crucial for the convection unit to redirect the heated air towards the center of the room. Observe the shape of your unit. If the case has a 90 ° angle on the top and its air outlet louvers are parallel to the floor, you might as well say that the redirection effect on hot air is not optimized. If, on the other hand, the design of the heater is curved and points towards the center of the room, then the redirection of the warm air will be much better. The Allegro II from Convectair is a very good example of an electrical convector whose shape is optimized to offer a better comfort to its users.
If you are looking for a new heater for this winter, convection heaters are a great option. However, be sure to make the right choice to maximize the heat distribution in your room. Your winters will never be the same again.
Étienne Bolze & Youri Cupidon