auxiliary heat vs emergency heat on Nest Thermostats: What’s the Difference?

With the advancement of technology, modern thermostats have revolutionized the way we control indoor climate, providing enhanced comfort and energy efficiency. Nest Thermostats, in particular, have garnered widespread acclaim for their cutting-edge features and intelligent design. 

Among the array of functionalities these smart devices offer, understanding the difference between Auxiliary Heat and Emergency Heat is crucial for maximizing their potential and ensuring optimal heating performance.

In this comprehensive guide, we delve into the world of Nest Thermostats and explore the distinctive roles played by auxiliary and emergency heat sources. Let’s begin!

Nest Thermostats 7 Basic Points

Nest Thermostats have revolutionized the way we interact with our home heating and cooling systems. 

Developed by Nest Labs, a subsidiary of Google, these smart thermostats have gained immense popularity for their intuitive interfaces, advanced features, and energy-saving capabilities. 

To comprehend the significance of auxiliary and emergency heat on Nest Thermostats, it’s essential to grasp the fundamental workings of these intelligent devices.

1. Smart and Connected

Nest Thermostats are at the forefront of the smart home revolution, designed to seamlessly integrate with modern living. 

They are equipped with Wi-Fi connectivity, allowing homeowners to control their heating and cooling systems remotely via smartphones, tablets, or computers. 

The ability to adjust temperature settings from anywhere empowers users with unmatched convenience and energy management.

2. Learning Capabilities

One of the standout features of Nest Thermostats is their ability to learn and adapt to users’ preferences over time. 

Through machine learning algorithms, these devices analyze homeowners’ behavior and patterns to create personalized heating and cooling schedules. 

As a result, Nest Thermostats can optimize energy usage while ensuring a comfortable living environment.

3. Sensor Technology

Nest Thermostats are equipped with an array of sensors that provide real-time data for precise temperature control. 

These sensors detect occupancy, humidity levels, and ambient conditions, enabling the thermostat to make informed decisions about when and how to adjust heating settings.

4. Energy Efficiency

One of the primary goals of Nest Thermostats is to promote energy efficiency. 

By utilizing machine learning and sensor data, these smart devices can automatically set temperatures at energy-saving levels when occupants are away, and adjust back to comfortable levels upon their return.

5. User-Friendly Interface

Nest Thermostats boast a user-friendly interface with a high-resolution display that allows users to interact with ease. 

Through the interface, homeowners can access detailed energy usage reports, set schedules, and configure various heating and cooling options.

6. Compatibility and Integration

Nest Thermostats are designed to be compatible with a wide range of heating, ventilation, and air conditioning (HVAC) systems. 

Whether it’s a conventional furnace or a heat pump, Nest Thermostats can seamlessly integrate into diverse HVAC setups.

7. Continuous Improvements

As part of Nest Labs’ commitment to innovation, Nest Thermostats receive regular software updates that introduce new features and enhance existing functionalities. 

This ensures that users always have access to the latest advancements in smart home technology.

4 Role of Heat Sources in Nest Thermostats

Nest Thermostats employ a sophisticated heating system that relies on multiple heat sources to maintain a comfortable indoor temperature. 

Let’s explore the primary heat source, auxiliary heat, and emergency heat, and how each plays a unique role in keeping your home cozy.

1. Primary Heat Source:

The primary heat source in Nest Thermostats refers to the main heating system responsible for maintaining the desired temperature in your home. 

This could be a central heating furnace, a heat pump, or a boiler, depending on the HVAC setup of your residence. 

The primary heat source is the go-to option for everyday heating needs when outdoor temperatures are within the thermostat’s designated comfort range.

2. Auxiliary Heat:

Auxiliary heat comes into play when the primary heat source alone is insufficient to meet the heating demands of your home. 

During particularly cold weather conditions or when the primary heat source cannot keep up, Nest Thermostats activate the auxiliary heat to provide supplementary warmth. 

Typically, auxiliary heat is generated by electric resistance heating elements, which are quick to respond and deliver immediate heat. 

While auxiliary heat is effective in bolstering your home’s warmth, it is worth noting that it consumes more energy than the primary heat source, making it essential to use it judiciously.

3. Emergency Heat:

Emergency heat serves as a fail-safe measure when the primary heat source malfunctions or is unavailable. 

For instance, if your heat pump develops an issue during extremely cold weather, the Nest Thermostat will engage the emergency heat mode to maintain a livable indoor temperature. 

Unlike auxiliary heat, which complements the primary source, emergency heat operates independently and relies on backup heating systems, such as electric resistance coils or a separate furnace. 

Due to its significant energy consumption, emergency heat should only be activated when absolutely necessary and for short periods.

4. Smart Heat Source Management:

The Nest Thermostat’s intelligence lies in its ability to dynamically manage these heat sources based on various factors. 

By continuously monitoring indoor and outdoor conditions, occupancy patterns, and weather forecasts, the thermostat optimizes the use of each heat source to strike a balance between comfort and energy efficiency. 

For example, during milder weather, the thermostat may rely solely on the primary heat source to conserve energy, while activating auxiliary or emergency heat sparingly during extreme conditions.

Auxiliary Heat: When and How It Operates?

Activation Triggers:

Auxiliary heat is typically activated under the following circumstances:

Temperature Differential: 

When the difference between the set temperature and the actual indoor temperature exceeds a certain threshold, the Nest Thermostat may engage auxiliary heat to reach the desired temperature more quickly.

Extreme Cold Weather: 

During exceptionally cold outdoor temperatures, the primary heat source, such as a heat pump, may struggle to extract sufficient heat from the outside air. 

In such cases, the thermostat activates auxiliary heat to supplement the heating capacity.

Defrost Cycle: 

Heat pumps occasionally enter defrost cycles to remove frost buildup on the outdoor unit during winter. 

During the defrost cycle, the heat pump temporarily switches to cooling mode, and the Nest Thermostat activates auxiliary heat to maintain indoor comfort.

Emergency Heat Pump Failure: 

If the primary heat source, such as a heat pump, experiences a malfunction, the Nest Thermostat can rely on auxiliary heat as a backup to keep your home warm until the issue is resolved.

Electric Resistance Heating:

When auxiliary heat is activated, it is commonly generated through electric resistance heating elements. 

These heating elements are located either in the indoor air handler (for forced-air systems) or within the heat pump’s outdoor unit. 

Electric resistance heating is quick to produce heat, ensuring that your home warms up promptly during cold spells.

Energy Consumption Considerations:

While auxiliary heat is indispensable during cold weather, it is essential to be mindful of its energy consumption. 

Electric resistance heating is less energy-efficient compared to the primary heat source, such as a heat pump or a gas furnace. 

Therefore, using auxiliary heat judiciously can help prevent significant spikes in energy consumption and utility bills.

Thermostat Settings and Optimization:

To optimize the use of auxiliary heat, consider the following tips:

Temperature Settings: 

Set your thermostat’s temperature appropriately to avoid frequent cycling between the primary and auxiliary heat sources. 

A moderate temperature setting can help prevent unnecessary auxiliary heat activation.

Use Programmable Features: 

Utilize the programmable scheduling features of your Nest Thermostat to align heating demands with your daily routines. 

This helps minimize auxiliary heat usage when the home is unoccupied or during nighttime hours.

Weather-Aware Features: 

Take advantage of Nest Thermostat’s weather-aware features, which factor in outdoor weather conditions to adjust heating settings. 

This can help reduce the reliance on auxiliary heat during milder weather.

Emergency Heat: When It’s Needed?

Activation Triggers:

Emergency heat is typically activated under the following circumstances:

Primary Heat Source Failure: 

If the primary heat source, such as a heat pump or furnace, malfunctions or is unable to provide sufficient heat, the Nest Thermostat will activate emergency heat to take over the heating duties.

Extremely Cold Weather and Defrost Cycles: 

In areas with frigid temperatures, heat pumps may struggle to extract heat from the outside air effectively. 

During extended periods of extreme cold or defrost cycles, the Nest Thermostat may activate emergency heat to ensure consistent indoor warmth.

Diagnostic Mode or HVAC System Errors: 

Some HVAC systems enter diagnostic mode or encounter errors that temporarily disable the primary heat source. 

In such situations, emergency heat can step in as a reliable backup heating solution.

Backup Heating Mechanism:

In Nest Thermostats, emergency heat relies on an alternative, standalone heating system that operates independently of the primary heat source. 

Commonly, emergency heat is generated using electric resistance heating elements, similar to the auxiliary heat mechanism. 

However, unlike auxiliary heat, which assists the primary source, emergency heat takes over as the sole heating source when activated.

Energy Consumption Considerations:

Emergency heat can be more energy-intensive than the primary heat source, especially if it relies on electric resistance heating. 

Therefore, it is crucial to use emergency heat sparingly and only when necessary. Extended use of emergency heat can result in higher energy bills, making it essential to address any issues with the primary heating system promptly.

Monitoring and Troubleshooting:

To ensure your Nest Thermostat’s emergency heat functions optimally, consider the following steps:

Regular Maintenance: 

Schedule regular maintenance checks for your HVAC system to prevent unexpected failures and minimize the need for emergency heat.

Prompt Repairs: 

Address any malfunctions or issues with your primary heating system immediately to avoid prolonged reliance on emergency heat.

Proper Use: 

Avoid using emergency heat as a substitute for routine heating; instead, treat it as an emergency measure and restore the primary heat source as soon as possible.

Reverting to Normal Mode:

After activating emergency heat, the Nest Thermostat will continue to use until the user manually reverts to the normal heating mode. 

Once the primary heat source is functional and the emergency situation has been resolved, it is crucial to switch back to the primary heating mode to ensure optimal energy efficiency.

Top 8 Efficiency and Energy Considerations

1. Leveraging Smart Learning:

One of the most significant advantages of Nest Thermostats is their ability to learn and adapt to your lifestyle. 

Take full advantage of this feature by allowing the thermostat to create personalized heating schedules based on your occupancy patterns. 

As the thermostat becomes familiar with your routine, it can automatically adjust temperatures to save energy when you’re away and ensure comfort upon your return.

2. Programmable Scheduling:

In addition to smart learning, manually programming your Nest Thermostat with specific temperature schedules further enhances energy efficiency. 

Customize heating settings to align with your daily activities, such as lowering temperatures when you’re at work or asleep, and raising them during active hours. 

This practice prevents unnecessary heating when it’s not needed, leading to considerable energy savings over time.

3. Weather-Aware Features:

Leverage the weather-aware capabilities of your Nest Thermostat to optimize heating based on external conditions. 

By factoring in outdoor weather data, the thermostat can make informed decisions about when to engage the primary heat source, auxiliary heat, or when to rely on natural indoor temperature regulation.

4. Temperature Setbacks:

Consider implementing temperature setbacks during times when occupants are away for extended periods. Lowering the temperature during such periods can substantially reduce energy consumption. 

With Nest Thermostats’ remote access, you can easily adjust settings from your mobile device, ensuring a warm home upon your return.

5. Regular Maintenance:

Ensure your HVAC system undergoes regular maintenance to maintain its efficiency and prevent potential breakdowns. 

Clean or replace air filters, inspect ductwork, and schedule professional HVAC servicing to keep your heating system in optimal condition.

6. Limit Emergency Heat Usage:

While emergency heat is indispensable during emergencies, avoid using it as a primary heating source for extended periods. 

Emergency heat, particularly if powered by electric resistance heating, can significantly increase energy consumption. Address any issues with the primary heat source promptly to minimize the need for emergency heat.

7. Home Insulation:

A well-insulated home helps retain heat and reduces the strain on your heating system. Ensure proper insulation in walls, windows, doors, and attics to create a more energy-efficient living space.

8. Energy Usage Reports:

Take advantage of the energy usage reports provided by your Nest Thermostat. These reports offer valuable insights into your heating patterns and energy consumption, enabling you to identify areas for improvement and adjust your habits accordingly.

Nest Thermostats Programming for Optimal Heating

Establishing a Comfortable Baseline:

Start by setting a baseline temperature that ensures comfort when you are at home. Consider factors such as personal preferences, the number of occupants, and any specific comfort requirements for different areas of your home.

Utilizing Programmable Schedules:

Leverage the Nest Thermostat’s programmable scheduling feature to create heating schedules that align with your daily routine. 

Set lower temperatures during periods when occupants are typically away, such as during work hours or nighttime. Raise the temperature to your desired comfort level during active hours.

Temperature Setbacks and Set-for-Time Feature:

Experiment with temperature setbacks during periods of prolonged absence, such as vacations. 

The Nest Thermostat’s “set-for-time” feature allows you to specify a temperature change for a defined duration, making it convenient to adjust settings for specific occasions.

Learning Mode and Adapting Preferences:

Let the Nest Thermostat’s learning mode adapt to your behavior over time. The more you use and interact with the thermostat, the better it becomes at understanding your heating preferences and adjusting accordingly.

Avoiding Drastic Temperature Swings:

While energy-saving setbacks are beneficial, avoid setting temperatures too low during winter or too high during summer, as extreme swings can lead to excessive energy consumption when the thermostat compensates to restore the desired comfort level.

Weather-Aware Features:

Enable the Nest Thermostat’s weather-aware features, which take external weather conditions into account when making heating decisions. This feature helps optimize heating strategies based on the current climate.

Multi-Zone Heating:

If your home has multiple heating zones, consider installing additional Nest Thermostats to independently control the temperature in different areas. 

This allows for more precise temperature management and energy efficiency.

Manual Temperature Adjustments:

In situations where the thermostat’s smart learning may not align with immediate preferences, manually adjust the temperature to meet your immediate comfort needs. 

The thermostat will learn from these adjustments and adapt over time.

Regularly Reviewing and Fine-Tuning:

Periodically review your Nest Thermostat’s settings to ensure they align with changing schedules or preferences. 

Fine-tune the programming as needed to maintain an efficient heating schedule.

Energy Usage Reports:

Regularly check the energy usage reports provided by the Nest Thermostat to gain insights into your heating patterns. 

Use this information to identify opportunities for further energy conservation and efficiency improvements.

Frequently Asked Questions (FAQ’s)

What Should I Do If My Nest Thermostat Becomes Unresponsive?

If your Nest Thermostat is unresponsive, try removing it from its base and reattaching it to restart the device. Check the thermostat’s power source, battery (if applicable), and Wi-Fi connectivity. If the issue persists, consult Nest support or perform a factory reset if necessary.

Can I Integrate My Nest Thermostat With Other Smart Home Devices?

Yes, Nest Thermostats are designed to integrate with various smart home ecosystems. They can connect with virtual assistants like Google Assistant or Amazon Alexa, allowing for voice-controlled temperature adjustments and seamless interactions with other smart devices.

How Often Should I Clean Or Replace The Filters In My HVAC System?

Regularly cleaning or replacing HVAC filters is essential for maintaining optimal system performance and indoor air quality. Check your HVAC system’s user manual for recommended filter maintenance intervals, as they can vary based on filter type and usage.

Should I Use Emergency Heat As The Primary Heating Source During Cold Weather?

No, emergency heat should only be used as a backup measure during emergencies or when the primary heat source is unavailable. Emergency heat, usually powered by electric resistance heating, consumes more energy than the primary source, so it should be used sparingly to avoid high energy bills.


Nest Thermostats have transformed HVAC management, offering smart learning, remote accessibility, and energy efficiency. Understanding auxiliary heat and emergency heat empowers users to strike a balance between comfort and conservation. 

By programming the thermostat with smart schedules and leveraging weather-aware features, homeowners can enjoy personalized comfort while saving energy. Troubleshooting common issues ensures seamless operation and swift resolutions. 

Take advantage of its innovative features, reduce energy consumption, and contribute to a greener world. Let your Nest Thermostat be the cornerstone of your efficient and modern HVAC system, providing comfort and control at your fingertips.

Scott Maupin