What Controls the Heating Elements in Most Electric Furnaces

“What Controls the Heating Elements in Most Electric Furnaces”

Electric furnaces are a staple in many households, providing a reliable source of heat during the colder months. But have you ever wondered what controls the heating elements in these devices? Understanding the components and mechanisms behind electric furnaces can help you maintain and troubleshoot your system more effectively. This article delves into the various controls that regulate the heating elements in most electric furnaces, ensuring efficient and safe operation.

Understanding Electric Furnaces

Electric furnaces convert electrical energy into heat through resistance heating elements. These elements, typically made of metal, heat up as electricity passes through them. The heat generated is then distributed throughout the home via a blower motor. The control of these heating elements is critical to ensure consistent and safe heating.

what controls the heating elements in most electric furnaces

Components of an Electric Furnace

Heating Elements

The heating elements are the core of an electric furnace, responsible for generating heat. They are made from high-resistance materials like nickel-chromium alloys, which produce heat when an electrical current flows through them.


Thermostats act as the control center for the furnace, regulating the temperature by switching the heating elements on and off. They maintain the desired temperature set by the homeowner, ensuring comfort and energy efficiency.

Blower Motor

The blower motor circulates air over the heating elements and distributes it throughout the home. Proper airflow is essential for effective heating and preventing the elements from overheating.

Control Boards

The control board is the brain of the furnace, coordinating the operation of various components. It receives signals from the thermostat and ensures the heating elements, blower motor, and other parts work in harmony.

Role of Heating Elements

Types of Heating Elements

Heating elements come in various forms, including coil, ribbon, and tubular types. Each has its advantages and applications, but all operate on the principle of electrical resistance heating.

How Heating Elements Work

When the thermostat signals for heat, the control board activates the heating elements. Electricity flows through the elements, causing them to heat up. The blower motor then pushes air over these hot elements, distributing warm air through the ductwork.

Thermostats and Their Function

Types of Thermostats

There are several types of thermostats, including programmable, non-programmable, and smart thermostats. Programmable thermostats allow for setting different temperatures at different times of the day, while smart thermostats can be controlled remotely via smartphone apps.

Thermostat Operation

The thermostat measures the ambient temperature and compares it to the set temperature. When the room temperature drops below the set point, the thermostat sends a signal to the control board to activate the heating elements. Once the desired temperature is reached, the thermostat turns off the heating elements.

Control Boards in Electric Furnaces

What is a Control Board?

A control board is an electronic circuit board that manages the operation of the furnace. It processes signals from the thermostat and other sensors to control the heating elements, blower motor, and other components.

Functions of a Control Board

The control board ensures that the heating elements turn on and off at the correct times, coordinates the blower motor’s operation, and monitors safety switches. It plays a crucial role in maintaining the furnace’s efficiency and safety.

Common Issues with Control Boards

Control boards can malfunction due to electrical surges, component wear, or manufacturing defects. Symptoms of a faulty control board include inconsistent heating, frequent cycling on and off, and error codes displayed on the thermostat.

Limit Switches and Safety Controls

Importance of Limit Switches

Limit switches are safety devices that prevent the furnace from overheating. They monitor the temperature inside the furnace and shut off the heating elements if the temperature exceeds a safe limit.

How Limit Switches Work

When the temperature inside the furnace rises too high, the limit switch interrupts the electrical flow to the heating elements, preventing further heating. This protects the stove from damage and reduces the risk of fire.

Safety Features in Electric Furnaces

Modern electric furnaces include various safety features such as limit switches, thermal fuses, and flame sensors. These components work together to ensure safe and reliable operation.

Sequencers in Electric Furnaces

Purpose of Sequencers

Sequencers control the order and timing of electrical loads in the furnace. They ensure that the heating elements and blower motor activate in a specific sequence to prevent electrical overloads.

How Sequencers Operate

Sequencers use a series of electrical contacts that open and close in response to temperature changes. When the thermostat calls for heat, the sequencer gradually activates the heating elements and blower motor, ensuring a smooth and controlled startup.

Electrical Relays and Contactors

Difference Between Relays and Contactors

Relays and contactors are both types of electromechanical switches, but contactors are designed to handle higher electrical loads. Relays are used for low-power applications, while contactors manage the high-power heating elements.

Their Role in Controlling Heating Elements

Relays and contactors control the flow of electricity to the heating elements. When the control board signals for heat, the relay or contactor closes, allowing electricity to flow to the heating elements. Once the desired temperature is reached, the relay or contactor opens, cutting off the electrical flow.

Blower Motor and Air Circulation

How Blower Motors Function

The blower motor is responsible for moving air over the heating elements and distributing it throughout the home. It operates in tandem with the heating elements to ensure efficient heat transfer and circulation.

Importance of Proper Airflow

Proper airflow is essential for the efficient operation of an electric furnace. Restricted airflow can cause the heating elements to overheat, leading to safety shutoffs and reduced efficiency. Regular maintenance, such as cleaning or replacing filters, helps maintain optimal airflow.

Troubleshooting Common Issues

Identifying Problems with Heating Elements

Common issues with heating elements include burnouts, electrical shorts, and physical damage. Symptoms of faulty heating elements include insufficient heating, uneven temperature distribution, and frequent cycling.

Diagnosing Thermostat Issues

Thermostat problems can manifest as inconsistent temperatures, unresponsive controls, and incorrect temperature readings. Checking the thermostat’s settings, batteries, and connections can help diagnose these issues.

Control Board Malfunctions

Control board malfunctions often present as error codes, inconsistent operation, and complete system shutdowns. Inspecting the control board for visible damage and loose connections and testing with a multimeter can help identify problems.

Fixing Blower Motor Problems

Blower motor issues can cause poor airflow, strange noises, and complete system failure. Regular lubrication, belt inspections, and motor replacements can address these problems.

Maintenance Tips for Electric Furnaces

Regular Inspections

Routine inspections help identify and address potential issues before they become significant problems. Checking electrical connections, inspecting heating elements, and testing safety switches are essential maintenance tasks.

Cleaning and Replacing Filters

Clean filters ensure proper airflow and efficient operation. To maintain optimal performance, filters should be checked monthly and replaced as needed.

Professional Servicing

Annual professional servicing ensures that your furnace operates safely and efficiently. A skilled technician can perform thorough inspections, clean components, and address any issues.

Energy Efficiency in Electric Furnaces

Tips to Improve Efficiency

Improving the efficiency of your electric furnace can reduce energy consumption and lower utility bills. Tips include sealing ductwork, using programmable thermostats, and ensuring proper insulation.

Benefits of Energy-Efficient Models

Energy-efficient furnaces offer significant cost savings over their lifespan. They use advanced technology to maximize heating efficiency, reducing energy consumption and environmental impact.

Upgrading Your Electric Furnace

When to Upgrade

Consider upgrading your furnace if it is more than 15 years old, requires frequent repairs, or is no longer efficient. Newer models offer improved performance, energy savings, and enhanced safety features.

Choosing a New Furnace

When selecting a new furnace, consider factors such as energy efficiency, heating capacity, and compatibility with your home’s existing ductwork. Consulting with a professional can help you make an informed decision.

Installation Considerations

Proper installation is crucial for the efficient and safe operation of your new furnace. To avoid potential issues, ensure that the installation is performed by a licensed professional.

FAQs: What Controls the Heating Elements in Most Electric Furnaces

How do I know if my heating element could be better?

If your furnace is producing enough heat or is heating unevenly, the heating element may need to be fixed. A professional inspection can confirm this.

Can I replace a heating element myself?

Replacing a heating element requires electrical knowledge and experience. It is recommended that a professional be hired to ensure safety and proper installation.

How often should I service my electric furnace?

Your electric furnace should be professionally serviced at least once a year to ensure optimal performance and safety.

What are the signs of a failing control board?

Signs of a failing control board include inconsistent heating, frequent cycling on and off, and error codes displayed on the thermostat.

How can I improve the efficiency of my electric furnace?

Sealing ductwork, using programmable thermostats, maintaining proper insulation, and performing regular maintenance can improve efficiency.

What safety features should I look for in an electric furnace?

Look for features such as limit switches, thermal fuses, and flame sensors. These safety components help prevent overheating and potential fire hazards.


Understanding what controls the heating elements in most electric furnaces is essential for maintaining a safe and efficient heating system. From thermostats and control boards to limit switches and sequencers, each component plays a critical role in ensuring your furnace operates effectively. Regular maintenance and professional servicing are vital to keeping your furnace in top condition, providing reliable warmth and comfort for years to come.