When Does a Heat Pump Switch to Emergency Heat? Stay Warm Without Wasting Energy ❄️

If you own a heat pump, you’ve probably noticed that your thermostat has an “emergency heat” option. But many homeowners wonder: when does a heat pump switch to emergency heat automatically, and when should you activate it yourself?

Emergency heat is designed as a backup, not the primary heating source. Using it incorrectly can drive your energy bills sky-high.

This guide will explain how emergency heat works, when it kicks in, and how to use a heat pump with emergency heat thermostat the right way.

When Does a Heat Pump Switch to Emergency Heat?

A heat pump usually switches to emergency heat when:

• Outdoor temperatures drop below 30–35°F and the heat pump struggles to extract heat.

• The main heat pump system fails (for example, a broken compressor).

• You manually set the thermostat to emergency heat mode.

Most modern systems will automatically engage backup heating coils or electric strips when they can’t keep up with demand.

Pro Tip: If your system frequently switches to emergency heat in mild weather, it may signal an underlying issue with your heat pump.

Heat Pump with Emergency Heat Thermostat

Your heat pump with emergency heat thermostat is built to keep you warm no matter what the weather does. But here’s the catch:

• Normal Operation: The thermostat tells the heat pump to pull heat from outside air.

• Auxiliary Heat: When the heat pump can’t meet demand, the system adds supplemental heat.

• Emergency Heat: The thermostat bypasses the heat pump completely and runs only the electric resistance coils or gas backup.

This is the most expensive heating mode, so use it only when absolutely necessary.

Why Emergency Heat Should Be Your Last Resort 🔥

While emergency heat will keep your home warm, it comes at a cost:

• High Energy Bills – Electric resistance heating can cost 2–3x more than regular heat pump operation.

• System Strain – Relying on emergency heat for long periods may shorten equipment lifespan.

• Troubleshooting Signal – If you need emergency heat often, schedule a service call.

Think of emergency heat as a spare tire—it’s there to get you through tough times, not for everyday driving.

Quick Reference: Heat Pump Heating Modes

Mode	How It Works	Cost	When to Use
Normal Heat	Heat pump extracts outdoor heat	Low	Everyday heating above 30–35°F
Auxiliary Heat	Heat pump + supplemental coils	Medium	Extremely cold days
Emergency Heat	Backup coils/gas only	High	Only if heat pump fails

FAQ: Emergency Heat and Heat Pumps

When does a heat pump switch to emergency heat? When outdoor temps are too low or the main system fails.

Should I set my thermostat to emergency heat manually? Only if your heat pump isn’t working.

Is emergency heat the same as auxiliary heat? No—auxiliary heat supplements the pump, while emergency heat bypasses it completely.

Does using emergency heat increase bills? Yes, it’s the most expensive heating mode.

How do I know if my thermostat is using emergency heat? The display will show “EM Heat” or “Emergency Heat” when active.

Conclusion

So, when does a heat pump switch to emergency heat? It happens automatically when the system can’t keep up in extreme cold, or when you manually set it. A heat pump with emergency heat thermostat ensures you always have a backup, but remember—this mode should only be used short-term to avoid skyrocketing energy costs.

Keep your system maintained, know when to switch modes, and you’ll stay warm without overpaying. ✅