Nest Thermostat Keeps Using Auxiliary Heat – How to Fix It

Anytime you use AUX heat instead of your heat pump, you risk significantly increasing the electricity bill. Making sure your Nest Thermostat doesn't switch to AUX heating is all about making the right settings.

Keep in mind that it is not uncommon for the AUX button to automatically turn on even when the pump is providing enough heat.

Nest app settings

Most people prefer to use the Nest app to adjust settings, as it doesn't require getting off the couch.

1. View your Nest app.
2. Tap “Settings”.
3. Locate and tap the Thermostat icon.
4. Press "Heat pump balance".
5. Choose between "Maximum savings" and "Disabled".

Nest thermostat settings

If you can't find your phone, you can still make the same changes using your thermostat.

1. Display the “Quick View” menu by pressing the thermostat ring.
2. Select “Settings”.
3. Go to “Nest Sense”.
4. Select “Heat pump balance”.
5. Choose between "Maximum savings" and "Disabled".

Heat pump balancing parameters

There are four settings to choose from, but only two of them are designed to really maximize energy efficiency and use less AUX heat.

Image source: Nest.com

1. Maximum savings
   This is the setting you need if you want to minimize AUX heat usage but not turn it off completely. “Maximum savings” ensures that your heating system operates with maximum energy efficiency to reduce costs. To achieve this, the heat pump will often start operating earlier in order to have enough time to reach the target temperature. The lockout temperature is set lower than usual but not at the lowest setting.
2. disabled
   Disabling “Heat Pump Balancing” means that the AUX heat will only come on based on what you have set as the lockout temperature. If you are using the lowest setting, your AUX heater will likely no longer fire and the notification will disappear. Of course, this will only happen if outside factors do not interfere.
3. Balanced
   The “Balanced” option helps a little with energy savings. However, this still allows the AUX heat to fire more than when using the previous settings. It does this in order to help reach the target temperature faster.
4. Maximum comfort
   If you don't care about energy savings, then 'Max Comfort' is the setting for you. It ensures that your home is always within the optimum temperature range you have set.

How to set the lockout temperature

Setting the lockout temperature is important if you want to minimize AUX heat usage. You can change it from the Nest app or from your thermostat.

1. Go to settings”.
2. Select “Equipment”.
3. Select “Heat pump”.
4. Switch to the desired value.

External factors that can trigger AUX heat

If you live in colder countries with harsh winters, the outside temperature can disrupt your heat pump. If the heat pump freezes, the AUX heat comes on more often, to compensate and raise the temperature to the desired levels.

The AUX heater may also start if the pump cannot handle the outside heat on cold winter nights. If the walls in your home are too cold and your heat pump is not powerful enough, AUX heat may be needed to compensate for the degrees.

Important Notes About Nest Thermostats

You don't need to connect your Nest Thermostat to your Wi-Fi network. It will still work properly, but you won't be able to use and configure the 'Heat Pump Balance' feature.

Sometimes the "Heat pump balance" option may be missing in Nest Sense. If so, you may need to recheck the thermostat wiring.

1. Remove the thermostat display.
2. Check the wire in the AUX/W2 connector.
3. If no wires are present, you have no AUX heat, which means “heat pump trim” is not available.
4. If both connectors W1 and W2 have wires, it means you are using a dual fuel system. “Heat pump balance” is not available for this type of system.

Note that you can still set a lockout temperature by following the previously mentioned steps: Settings > Equipment > Heat pump.

Latest Thoughts

Unless your wiring is down, Nest systems rarely send AUX heat notifications for no reason. If your heating system supports an AUX heating function, you should make the appropriate configuration according to your personal needs and preferences.

Nest Sense gives you extensive control over your heating system. This means that barring unfortunate and unforeseen external interference, you can avoid using AUX heat to achieve the target temperature all winter long.