Emergency Heating Mode: Understanding Its Real Impact on Your Energy Costs
At AirGreen, we’re frequently called to service homes in Montréal, Laval, Longueuil, as well as on the North Shore and South Shore, where customers are concerned about higher electricity bills after using their wall-mounted heat pump in emergency heating mode. It’s true—this operating mode can lead to significantly higher costs. But under what conditions exactly, and more importantly: how can it be avoided or controlled effectively?
What Is Emergency Heating Mode?
On most modern wall-mounted heat pumps, emergency heating mode (often displayed as "Emergency Heat") allows the system to provide heat without using the outdoor compressor, relying instead solely on a backup electric heating element. This mode is useful in the following cases:
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Compressor or outdoor fan failure
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Extremely cold weather (below -20°C)
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Auto-defrost malfunction
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Detected system anomalies (sensor or pressure error)
But while this mode is convenient, it consumes much more electricity than standard operation using reverse-cycle technology.
Real Case Study: AirGreen Call in Blainville
This past January, a customer in Blainville (North Shore) contacted us after noticing a sudden spike in their Hydro-Québec bill. They had a Gree Lomo 18,000 BTU wall-mounted heat pump installed two years prior and had manually switched on the emergency heating mode during a week of extreme cold.
Upon inspection, our team found:
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No mechanical failures
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The system had remained stuck in emergency mode
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The wall thermostat had not been reset to automatic mode
After resetting the system and updating the controller, the customer’s heat pump returned to normal operation—avoiding several more weeks of excessive energy use.
Result: quick return to normal, no parts replaced, and an immediate positive effect on future bills.
Emergency Mode Heating: Up to Three Times More Expensive
Prolonged use of emergency heating mode leads to a sharp increase in electricity consumption, as the unit stops functioning as a heat pump and instead becomes a basic electric heater.
Here’s how it compares:
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Standard mode (heat pump): 1 kWh = 3 to 4 kWh of heat (COP of 3 to 4)
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Emergency mode: 1 kWh = 1 kWh of heat (COP of 1)
This means your costs can triple, especially if you're heating multiple rooms or a large area.
How to Know If Your System Is Running in Emergency Mode?
Visible Signs:
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Thermostat screen displays "Emergency Heat"
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Outdoor compressor isn’t running, even during cold weather
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Warm air is blowing continuously, without modulation
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Your heat pump sounds louder or seems overworked
If you’re unsure, having an AirGreen technician verify it can save you weeks of extra energy costs.
Why Would Your System Activate Emergency Mode Automatically?
Some wall-mounted heat pumps switch to emergency mode automatically when a critical parameter is detected:
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Faulty outdoor temperature sensor
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Outdoor fan blocked by ice
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Improper airflow readings
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Refrigerant pressure error
These issues might seem minor… but they must be quickly resolved to avoid needlessly switching to backup electric heating.
Prevent Rather Than React: Smart Tips from AirGreen
1. Schedule a full HVAC maintenance before winter
Preventive maintenance allows you to:
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Clean coils and filters
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Verify defrost functionality
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Test pressure switches and temperature sensors
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Calibrate the wall thermostat
2. Don’t Manually Activate Emergency Heating Mode
Unless truly necessary, this mode should only be used on a technician’s recommendation or in case of actual system failure.
3. Monitor Your Usage via Hydro-Québec’s App or Your Smart Meter
A sudden spike in usage is often a clear indicator.
AirGreen: Your Partner for Energy-Efficient Heating
Our team of professionals responds quickly in Montréal, Laval, Longueuil, the North Shore, and the South Shore to:
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Diagnose unintentional switches to emergency heating mode
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Reset your system
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Correct sensor or configuration errors
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Optimize settings to prevent overconsumption
We also help you select high-performance models like the Fujitsu KZAH, Midea25, or Bosch IDS Premium R-454B, all specifically designed to handle Québec’s winter without needing backup electric heat.
Final Thought: Vigilance Pays Off
Emergency heating mode is a valuable safety net, but should never become a habit. Its high power draw, combined with users often not realizing it's activated, can send your utility bills soaring without warning.