Is Auxiliary Heat and Emergency Heat the Same? Understanding Your HVAC System
Many homeowners are confused about the difference between auxiliary heat and emergency heat, especially when facing chilly weather. While both systems provide supplemental warmth when your primary heating source struggles, they are distinct and operate differently. This article clarifies the nuances, helping you understand how each works and when to use them.
What is Auxiliary Heat?
Auxiliary heat is a secondary heating system that kicks in when your primary heating source, usually a heat pump, can't keep up with the demand to heat your home. Heat pumps are highly efficient at moderate temperatures, but their effectiveness diminishes significantly as outdoor temperatures plummet. This is where auxiliary heat steps in. It's typically electric resistance heating, a less efficient but reliable backup. Think of it as a supplemental boost to your heat pump, allowing it to maintain a comfortable indoor temperature even during colder spells. It's designed to be used in conjunction with the heat pump, not as a standalone heating source.
What is Emergency Heat?
Emergency heat, on the other hand, is usually a purely electric resistance heating system that acts as a last resort when your primary heating system fails completely or is entirely inadequate for the weather conditions. Unlike auxiliary heat, which works with the primary system, emergency heat takes over completely. It provides direct, electric resistance heating, often resulting in higher energy bills than relying solely on a heat pump or furnace. This mode should only be used when necessary, as its continuous use is significantly more expensive than using your main heating system.
What is the difference between auxiliary heat and emergency heat?
The key difference lies in their purpose and how they interact with your main heating system:
- Auxiliary Heat: A supplemental system that assists the primary heating source when it's struggling, typically a heat pump. It's designed for short-term use to help the primary system maintain comfort levels.
- Emergency Heat: A standalone, fully electric resistance heating system that acts as a backup when the primary heating system is malfunctioning or insufficient for the cold temperatures. It provides full heating capability but at a much higher cost.
How does auxiliary heat work?
Auxiliary heat in a heat pump system uses electric resistance coils to generate heat. When the outdoor temperature drops below a certain point, the system automatically switches on these coils to supplement the heat pump's output, preventing the indoor temperature from dropping significantly.
How does emergency heat work?
Emergency heat also uses electric resistance coils. However, it bypasses the heat pump entirely, directly heating the air without the benefit of the heat pump's heat exchange process. It runs continuously until you switch it off or the temperature reaches your setpoint.
When should I use auxiliary heat?
Auxiliary heat is automatically engaged by your thermostat when the heat pump is struggling to maintain your desired temperature, typically during periods of extreme cold. You generally don't need to manually engage it.
When should I use emergency heat?
Use emergency heat only when your primary heating system (heat pump or furnace) malfunctions or is completely unable to provide sufficient heat for your home. This could be due to a malfunctioning heat pump, a power outage affecting the heat pump, or extremely low outdoor temperatures.
Which is cheaper to run, auxiliary heat or emergency heat?
Auxiliary heat is significantly cheaper to run than emergency heat. Because it supplements your heat pump, it's only used intermittently, and the heat pump’s efficiency is still partially in play. Emergency heat, relying solely on electric resistance heating, is far less efficient and consequently much more expensive to operate.
Why is my heating bill so high when using emergency heat?
Electric resistance heating is inherently less efficient than heat pumps or furnaces. It converts electricity directly into heat with minimal energy loss, but the overall energy consumption is much higher compared to other methods. Therefore, prolonged use of emergency heat will dramatically increase your energy bill.
By understanding the differences between auxiliary and emergency heat, you can better manage your HVAC system and potentially save money on your energy bills. Remember to consult your HVAC system's manual or a qualified technician for specific advice tailored to your system.
