Space Heaters

Convector heaters - everything you need to know about the popular heating method

Heating Trends, last updated on November 15, 2022

Convector heaters are a popular choice in places where electric heating is the only option, or the least expensive option. Find out the working principle of convectors and how they are used.


Convector heaters - everything you need to know about the popular heating method

What is a convector heater

Convector heaters, also known as convection heaters, Swedish or Norwegian radiators, or simply convectors, rely on the natural circulation of air in order to heat it as efficiently as possible. A convector heater or radiator takes cold air from the bottom, sends it through a heater that heats that air, and then releases it through the upper opening. Such air circulation enables the room to heat up quickly.

Although fan heaters also heat the air, convector heaters have several key advantages over them. The first is that they do not make a lot of noise like fan heaters. The second is that they heat the space more evenly, and the third is that they are safer. Since their surface does not heat up, they cannot ignite materials in their vicinity. If you are going to compare oil and convector radiators, know that the convector will heat the room faster.

Convectors are ideal for installation under windows. Usually mounted at floor level on external walls and under windows, convectors allow air to move upwards to counteract cold drafts and reduce condensation. Available in a variety of sizes, configurations and colors, convectors also offer design and installation versatility. Convector radiators are easily mounted on the walls and allow you to precisely determine the temperature for each room. Different models also come with different options, such as delayed ignition and shutdown, digital LCD control panel, safety limiter in case of overheating, etc.

Convectors have a wide range of control options from built-in thermostats to control individual units to rectifier controls that can be integrated into building management systems.

A convector heater or radiator takes cold air from the bottom, sends it through a heater that heats that air, and then releases it through the upper opening.

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How does a convection heater work

Using a natural phenomenon known as convection, the air inside the convector is heated and made less dense than the surrounding cold air, allowing it to rise due to buoyancy. As the heated air rises, the cooler air on the floor is drawn into the convector, creating a steady flow. By placing the convector under the window, the heated air rises and blocks the draft of cold air, creating a heated air curtain.

All convectors contain two components that work together to safely deliver heated air into the room: the heating element and the thermostat.

The heater converts electricity into heat by passing an electric current through a specially designed resistance wire. The elements used in convectors are coated with metal and are made of spirally wound resistance wire encapsulated in insulating powder (magnesium oxide, MgO) wrapped in a metal sheath.

Fins are added to the element bars to improve heat transfer by creating a chimney effect, directing air to flow over the element and a larger fin area to heat the air passing through the unit. Most convection heaters have aluminum fins attached to the main rod.

Thermostats are used to measure temperature, and are located near or in the heater housing itself, and interrupt the flow of electricity to the heater in case of overheating. In convectors, overtemperature limiting thermostats are most often activated when the air inlet or outlet is blocked by curtains or furniture, causing heat to build up.

Where to place convector heaters

Convectors are usually placed along the perimeter of the rooms to block the air flow caused by the cold outer wall that cools the air next to it and to prevent transmission losses. In most cases, convectors are mounted at floor level along an exterior wall and below a window, allowing heated air to rise from the top of the unit and block cold "draft" air.

Convectors will draw cooler air from the floor, heat it and then release it towards the ceiling where it cools, falling back to the floor to complete the cycle. This cycle or rotation effect works best with low to mid-height ceilings.

For efficient heating of multi-storey buildings with large windows, a second series of convectors can be switched on at each floor level to prevent the cascading effect of drafts. While the rising heated air blocks the downward flow, it also creates a curtain of warm air that acts as a buffer to prevent heat loss from the space to the cold wall.

Maintaining a pleasant home temperature

Since convectors have no moving parts and use natural air flow instead of forced air flow (fan), they are ideal for quiet living spaces. This includes bedrooms and home offices where convectors can be placed along exterior walls below windows to provide quiet, gentle warmth.

However, when installing the convector, it is necessary to ensure sufficient space on the wall for placing furniture and curtains, and it is necessary to take into account the position of the electrical sockets. Convectors with electronic hydronic elements have a lower surface temperature than standard convectors, making them a safe choice for a nursery or children's room.

For basements, standard convectors should be placed next to above-ground walls to eliminate cold drafts, as well as under windows next to other walls. Basements divided into several rooms should have a convector and a thermostat in each room. In large open basements, several smaller heaters will produce a better distribution of heated air than one large heater. If the space is only used occasionally, portable convectors may be a better choice. Basement heating has the added benefit of heating the floor of the rooms above, thus increasing the comfort level of the upper floors.

Thermostats and control methods

In addition to determining the appropriate type of convector for use in the space, the type of thermostat to be used should also be considered. Thermostats can be integrated or remote.

However, because integrated thermostats on heaters are mounted at or near floor level, they are best used in rooms that are not in constant use or require strict temperature control. Remote thermostats can be placed in rooms where we want to ensure maximum comfort without major temperature fluctuations, which requires additional wiring costs between the heater and the thermostat.

Thermostats are usually not placed on exterior walls, above a heater, above any heat-producing appliances (coffee stations, photocopiers or machines), or too far from the heater.

Convectors can be controlled individually using a built-in thermostat, collectively using an automation system (including a WiFi application) or combinations.