How Do Electric Heaters Work?

Electric heaters are a crucial component in many modern HVAC systems, providing heat for winter in moderate climates. Electric heating elements provide the heat in central air conditioners. In heat pump systems, electric heaters provide emergency or backup heat when the compressor system can’t supply enough heat during extremely cold weather.

Let’s explore how electric heaters work in HVAC systems. We’ll look at their components, and why they’re an efficient solution for many homes.

The Basics of Electric Heating

Electric heating elements work by converting electrical energy into heat through a process called resistance heating. When an electric current passes through a material with high electrical resistance, the material generates heat. This heat is then distributed throughout the home using the air circulation system of the central air conditioner.

Key Components of an Electric Heating Element

Heating Coils

These are typically made from a durable, high-resistance metal such as nichrome (an alloy of nickel and chromium). When electricity flows through the coils, they heat up and glow, producing infrared radiation and warming the air.

Insulators

Surrounding the heating coils are insulators that prevent the heat from escaping to unintended parts of the system, ensuring efficient energy use and safety.

Blower Fan

The central air conditioner’s blower fan circulates air across the heated coils, distributing the warmed air through the ductwork to heat your home evenly.

Thermostat and Sensors

The thermostat regulates the temperature by controlling when the heating element turns on and off. Sensors monitor the temperature of the coils and surrounding areas to prevent overheating.

How Electric Heaters Operate in Central Air Conditioners

Here’s the step-by-step process of how electric heaters work in central AC systems:

1. Thermostat Activation

When the thermostat detects that the indoor temperature has dropped below the desired level, it signals the system to activate the heating mode.

2. Control Sends Power to the Heating Element

Electricity flows to the heating element. The high resistance of the heating coils converts this electrical energy into heat.

3. Air Circulation

The system’s blower fan pulls cool air from your home and passes it over the heated coils. As the air absorbs the heat, it warms up and is then pushed back into your living spaces through the ductwork.

4. Temperature Regulation

Sensors and the thermostat work together to maintain a consistent temperature. Once the desired temperature is reached, the heating element shuts off temporarily, conserving energy.

How the Electric Heater Works in a Heat Pump

In extremely cold weather, when the outdoor air holds less heat to extract, heat pumps may struggle to meet your heating needs. This is where the electric heater steps in, acting as a reliable backup to support the compressor and sealed system.

Supporting the Heat Pump During Cold Weather

Heat pumps rely on a refrigeration cycle to transfer heat from the outside air into your home. However, as outdoor temperatures plummet, the heat pump’s efficiency decreases, and the amount of heat it can extract diminishes. At this point, the system’s thermostat signals the need for supplemental heat—also called auxiliary heat.

Here’s how the electric heater works in a heat pump:

1. Activation: The thermostat activates the auxiliary electric heating element when the indoor temperature falls below the set point and the heat pump alone cannot heat your home.
2. Heating Process: Electricity flows through high-resistance heating coils (usually made of nichrome), generating heat. The heat pump sealed system continues running to provide as much heat as possible.
3. Distribution: The system’s blower fan pulls air from your home, passes it over the hot coils, and circulates the warmed air through the ductwork.
4. Cycling: The thermostat cycles the heating element and heat pump on and off as needed to maintain the set temperature.

This process ensures your home remains comfortable when the heat pump itself isn’t able to adequately heat your home. When outside temperatures rise enough for the heat pump to handle home heating on its own, the electric heater shuts off.

Emergency Heat

When the heat pump’s sealed system or compressor fails or won’t be able to heat the home because of extremely low outside temperatures, the electric heating element becomes the primary heat source. This is typically controlled by the system’s emergency heat mode, which is manually activated via the thermostat in some heat pump systems.

Some heat pump systems automatically shift to emergency heat when the control senses that the heat pump system won’t be able to adequately heat the home.

Here is how the electric heater works in heat pump systems that automatically switch to emergency heating mode:

• Emergency heat is used by some heat pump systems to initially warm the interior air when you initially turn on the heat pump and the inside air in your home is well below the set temperature on the thermostat.
• Emergency heat may also kick in automatically to heat the home initially if the heat pump was disabled during a power outage and your home’s interior is too cold for the heat pump sealed system to heat up efficiently.
• When emergency heat is controlled automatically by the thermostat, the emergency heat will shut off when no longer needed and the heat pump and/or auxiliary heat can take over and efficiently heat your home.

In emergency mode, the heat pump’s sealed system components are bypassed entirely. Only the electric heating element is used for heating.

Since the heating element works independently of the outdoor unit, it provides reliable heat until the system can be repaired or until the heat pump sealed system can kick in and warm your home (along with auxiliary heat if needed).

While emergency heat is invaluable in a pinch, it is less energy-efficient than the standard heat pump operation and should be used sparingly in a system with a manual emergency heating switch.

Maintenance and Usage Tips for an Electric Heater

Here are some helpful usage and maintenance tips for using your electric heater or heat pump during winter.

Energy-Saving Usage Tips

Save money on your electric bills by following these energy-saving tips during winter:

Electric Heater and Heat Pump Maintenance Tips

Maintaining your electric heater or heat pump is key to ensuring it runs efficiently and lasts for many years. Regular heating system maintenance helps prevent breakdowns and keeps your system working smoothly throughout the year. Here are some simple steps you can take to keep your heat pump in good condition:

• Regular Inspections: Schedule professional HVAC maintenance yearly to have your heating and cooling system cleaned and inspected by a certified technician. The HVAC technician will catch any potential issues early and ensure everything is running as it should.
• Filter Replacement: Replacing the air filters is essential for maintaining proper airflow and keeping dust and debris out of your system.
• Cleaning Coils: Both the indoor and outdoor coils should be cleaned on a heat pump to periodically to ensure heat can transfer efficiently.
• Inspect Ductwork: Make sure the ducts are free of leaks or blockages that could reduce the system's efficiency and performance.

If your electric heater or heat pump shows signs of trouble, prompt heating system repair service can prevent small issues from turning into costly repairs.

Electric heaters in central air conditioners and heat pumps are a versatile and efficient solution for maintaining indoor comfort year-round.

By understanding how these systems work and adopting energy-efficient practices, you can enjoy a warm, cozy home during the winter months without worrying about excessive energy costs.

Remember, Sears Home Services is always here to help you with any heating system repair or maintenance need.