What Are Duct Heaters? Installation and Applications Duct Heaters

Duct heaters are a component of your HVAC system that preheats the air until it is circulated to your property’s rooms. Electrical duct heaters are the most common kind. When passing an electric current through the resistance, they generate heat (coils). The air flowing through absorbs the heat from the coils and is then drawn into your rooms through the ductwork. Electric duct heaters inline may be used for room, secondary, or primary heating.

In addition to the heating coils, there are some additional functions of electric conduit heaters. They can only be heated at certain hours of the day, or they can drop below the predefined value after temperatures have been set. By automatically flipping the heaters on and off, the best temperature can be maintained following measurements from climate control systems. This enables highly energy-efficient electric inline heaters.

These systems also have a range of safety switches. When the target temperature is hit, the first key immediately turns off the radiator. The second is a manual button that can be used to turn off the heaters if the automatic mechanism fails. Simpler models consist of a series of phases. Each stage consumes more energy to produce more heat. Typically, there are three phases.

Types of Duct Heaters

There are four ways to heat air, and they are as follows:

  • Open coil heaters,
  • Strip heaters,
  • Tubular heaters;
  • Quartz heaters

Open Coil Heaters

Open coil heaters are best suited for environments where the air velocity is less than 80 feet per minute. Higher velocities will allow the coils to come into contact with each other, causing them to short out. Because of the short reaction time and the low mass of these heaters, a phase angle SCR is preferred over a zero-cross fired SCR.

Strip and Tubular Heaters

Strip and tubular heaters are used to generate hot air and come in a variety of sizes. They are commonly used in ovens and as comfort heaters. Finned-tubular and strip heaters may be used if the appropriate temperature is less than 500 degrees F. An electric Tubular Heater of this kind without fins is suitable for higher temperatures of up to 1200 degrees F.

Quartz Heaters

Quartz heaters can endure 10 PSI input pressure and work up to 1500 F. These types of heaters are used for the medical packaging sector, heat shrinkage, cooling, bending, adhesives curing, and molded parts deflashing.

The three key factors used to determine the appropriate type of electric Cartridge Heater for a specific application are air pressure, volume, and velocity.

How They Work

Electric vent heaters operate by heating the air that passes through them. Since unfiltered air may contain grease, soil, or water, the air must be passed over the heating element even after the heater has been turned off. For this reason, a time delay relay is often used. This is particularly true for open coil heaters.


These machines could be located in office buildings, classrooms, industrial centers, power plants, and a variety of other locations. Duct heaters are simple to mount and repair. Airflow in any direction may be mounted using a regular spigot attachment to spiral ducting. With the safety cut-outs at the top of the unit, electric inline duct heaters can still be installed.

Be very careful in selecting a vent heater substitute. These devices are built by size, watt, and current, so you must have at least one model with the same stats.

Purpose of Duct Heaters

Duct heaters are an excellent means of maintaining rooms or distinct spaces at varying temperatures. The installation and maintenance are simple. That is why these instruments are used in many applications along with their energy efficiency. Regular cleaning is of the essence. You should check its state sometimes when you have a heating element. For domestic estate, at least until each winter season.


  • Primary heating;
  • Secondary heating;
  • Space heating;
  • Reheating;
  • Multi-zone and VAV heating.