How Much Power Do Car Heaters Use?

Understanding the power consumption of a car heater is crucial for both performance and energy efficiency. This article explores the factors influencing the power usage of car heaters, especially in both combustion and electric vehicles.

Combustion Engine Vehicles

When considering a car heater in a combustion engine vehicle (ICE), the heat itself is a byproduct of the engine's operation. This waste heat, which would otherwise be released through the radiator, is captured and directed to the car's heating system. Therefore, the heater itself does not consume additional power.

However, the blower motor, which circulates the warm air throughout the cabin, does use power. Typically, a blower motor in a combustion engine vehicle may draw around 12 amps on high speed. The power consumption can be calculated as follows:

12 amps X 14 volts 168 watts.

Electric Vehicles (EVs) and Hybrid Vehicles

For electric and hybrid vehicles, the situation is more complex. In these cases, the heater can use several kilowatts of power from the battery to generate heat. The amount of power used depends on the vehicle’s design and the efficiency of its thermal management system.

Factors Influencing Car Heater Power Consumption

Blower Motor Power

The power consumption of the blower motor can vary depending on the settings. Blower motors operating at their highest speed can draw between 18 and 25 amps of DC power. This is significant, especially considering the base power consumed by the fan to push warm air into the vents.

The power required to run the blower motor and its controls will also vary. Typically, this range is from 10 to 20 amps.

Engine Coolant Heat in ICE Vehicles

Additionally, some cars use engine coolant heat to warm the air circulated through the cabin. In such systems, the primary power consumption comes from the electric fan that pushes the warm air through the vents. This fan typically draws between 10 and 20 amps of power.

Conclusion

Understanding how car heaters use power is essential for maintaining a vehicle’s optimal performance and efficiency. For ICE vehicles, the blower motor uses the most power, while for EVs and hybrids, both the blower motor and the thermal management system play a significant role in power consumption.

With increasing attention to energy efficiency and environmental impact, it's useful to know that the primary power consumption in a car heater is due to the electric fan, not the generation of heat itself. This knowledge can help drivers make informed decisions to optimize their vehicle's performance and reduce energy use.