Understanding Emergency Heat: What You Need to Know
Every winter, we receive numerous questions about Emergency Heat: What is it? When should you use it? And why does it make your electric bill so high? Let’s clear up the confusion and provide some clarity on this important topic.
What is Emergency Heat?
When it’s cold outside, your heating system works to keep your house warm, usually a gas furnace or electric heat pump. If you have a heat pump, there are two heating modes on the thermostat: HEAT and EMERGENCY HEAT. Emergency Heat, also known as Auxiliary Heat, refers to electric resistance heating. This involves little coils of wire with an electric current running through them in your air handler, similar to what you see in a hair dryer. While electric resistance heaters are reliable and inexpensive, they are only 100% efficient—meaning one unit of energy consumed equals one unit of heat produced.
The Efficiency of Heat Pumps
What if, instead of creating heat, we could move existing heat into the house? That’s exactly what a heat pump does. It transfers heat energy from outside to inside using a refrigerant cycle, much like a refrigerator in reverse. This process allows heat pumps to be more than 100% efficient because they are moving heat rather than generating it. This is what happens when a heat pump’s thermostat is set to HEAT mode. Pretty cool, right?
Why Have a Backup?
Heat pumps, while efficient, can be a bit finicky. They need to work harder when there’s not enough heat to move around, they don’t perform well with ice buildup, and like any equipment, they can break down. That’s why having a backup source of electric resistance heat is a smart idea.
Common Misconceptions
Some homeowners believe that heat pumps don’t work in cold weather and switch to EMERGENCY HEAT mode when temperatures drop. However, most modern thermostats are designed to automatically activate auxiliary heat when needed, typically in three scenarios:
- When the heat pump can’t recover heat quickly enough due to extreme cold.
- When the thermostat set point is manually adjusted significantly higher.
- When the outside compressor detects frost and goes into defrost mode.
During defrost mode, the heat pump temporarily switches to air conditioning mode to melt ice off the outside unit, using auxiliary heat to ensure warm air continues to flow inside.
When to Manually Use Emergency Heat
You should only manually switch to EMERGENCY HEAT mode if your heat pump is malfunctioning and you need to keep your house warm while waiting for repairs. In rare cases, such as during freezing rain, ice could build up on the compressor fan fins and potentially cause damage. In this situation, running EMERGENCY HEAT mode can prevent the compressor fan from spinning and protect your equipment. However, this is an uncommon scenario.
Impact on Your Electric Bill
Be careful not to activate EMERGENCY HEAT mode inadvertently, a very easy mistake to make. Using EMERGENCY HEAT or AUX mode can significantly increase your electric bill compared to regular HEAT mode. Only use these settings in true emergencies when you need immediate warmth.
If you have any questions about your HVAC equipment or want to learn more about energy efficiency, contact the energy experts at Craighead Electric Cooperative. Don’t forget to check out our free energy audit program to help you save on your energy bills.
Stay warm and stay informed!
