Nest E Thermostats

[BMAC2]

House we bought has preinstalled Nest Thermostats divided into 6 Zones. All are set to Eco. Only 2 thermostats have C wires.

Should all thermostats have C wires? 

Why only 2?

When I raise the temperature I get a message which states the time it will take to reach temp. How does Nest calculate the delay time? The thermostat does not know the size of the area it is heating. Is the delay time based on previous heating history ?

Thanks

[zoeuvre · Accepted solution]

Hi BMAC2, 

Thanks for posting. The use of a C wire (common wire) in a thermostat installation depends on various factors, including the specific HVAC system and the power requirements of the thermostat. The C wire provides a continuous power supply to the thermostat, which can help ensure proper functionality and prevent power-related issues. While it's generally recommended to have a C wire connected to each thermostat, it's not always necessary. Some thermostats, including Nest Thermostats, can operate without a C wire by utilizing alternative power sources or power-saving features. However, using a C wire can provide a more stable power supply, especially in cases where the HVAC system or the thermostat requires more power or experiences power-related issues. Learn about the common or C wire here in this article. 

The reason why only two of the thermostats in your home have C wires could be due to the specific wiring configuration and setup of your HVAC system. It's possible that those two thermostats require a C wire for proper functionality or compatibility with the system, while the other thermostats can operate without it. The decision to use or not use a C wire might have been made by the previous homeowner or installer based on the specific requirements of each thermostat and the available wiring infrastructure.

Regarding the delay time displayed when raising the temperature on your Nest Thermostat, it's important to note that Nest Thermostats use advanced algorithms and machine learning to estimate the time it takes to reach the desired temperature. While the thermostat doesn't have specific knowledge of the size of the area it is heating, it uses historical data, environmental conditions, and the performance characteristics of the HVAC system to make its estimations. The delay time calculation takes into account factors such as the temperature differential, the HVAC system's capacity, and the rate at which the system can heat or cool the space. The more the thermostat learns about your home's heating and cooling patterns, the more accurate its estimations can become over time.

Let us know if that helps.

Best,

Zoe

[zoeuvre · Accepted solution]

Hi BMAC2, 

Thanks for posting. The use of a C wire (common wire) in a thermostat installation depends on various factors, including the specific HVAC system and the power requirements of the thermostat. The C wire provides a continuous power supply to the thermostat, which can help ensure proper functionality and prevent power-related issues. While it's generally recommended to have a C wire connected to each thermostat, it's not always necessary. Some thermostats, including Nest Thermostats, can operate without a C wire by utilizing alternative power sources or power-saving features. However, using a C wire can provide a more stable power supply, especially in cases where the HVAC system or the thermostat requires more power or experiences power-related issues. Learn about the common or C wire here in this article. 

The reason why only two of the thermostats in your home have C wires could be due to the specific wiring configuration and setup of your HVAC system. It's possible that those two thermostats require a C wire for proper functionality or compatibility with the system, while the other thermostats can operate without it. The decision to use or not use a C wire might have been made by the previous homeowner or installer based on the specific requirements of each thermostat and the available wiring infrastructure.

Regarding the delay time displayed when raising the temperature on your Nest Thermostat, it's important to note that Nest Thermostats use advanced algorithms and machine learning to estimate the time it takes to reach the desired temperature. While the thermostat doesn't have specific knowledge of the size of the area it is heating, it uses historical data, environmental conditions, and the performance characteristics of the HVAC system to make its estimations. The delay time calculation takes into account factors such as the temperature differential, the HVAC system's capacity, and the rate at which the system can heat or cool the space. The more the thermostat learns about your home's heating and cooling patterns, the more accurate its estimations can become over time.

Let us know if that helps.

Best,

Zoe

[BMAC2]

Zoe,

Thank you..Your answer was very helpful. One last question. We have all thermostats set to Eco most of the year. However in winter everyone has a different definition of comfort so settings change from room to room. Does this make the system less efficient? Does each thermostat remember previous settings or does it have to relearn each time we make a change?

Thanks again..

BMAC2 

[zoeuvre · Accepted solution]

Hi there, 

Thanks for getting back to us, and I'm sorry for the late response. With multiple Nest Thermostats set to Eco mode, each thermostat operates independently based on its own temperature and occupancy sensors. When a room's temperature falls outside the Eco temperature range, the thermostat will activate the heating or cooling system to adjust the temperature.

If different rooms require different comfort levels, it's possible that the system may experience some inefficiency. For example, if one room needs to be heated while another room is already at the desired temperature, the heating system may run longer than necessary, potentially resulting in energy waste. Regarding the learning capabilities of the Nest Thermostat, it does have a learning feature that adapts to your preferences over time. However, changes made to the temperature settings or switching between Eco mode and other modes won't necessarily affect the learning process. Each thermostat operates based on its current settings and the immediate temperature conditions in its location.

If you frequently adjust the settings or have different preferences in different rooms, it may help to create custom schedules for each thermostat. By setting specific temperature targets for different times of the day, you can have more control over the comfort levels in each room without relying solely on the Eco mode. Additionally, you can consider using Nest Temperature Sensor in conjunction with your Nest Thermostats. These devices allow you to monitor and control temperatures in specific rooms, ensuring that each area is maintained at its desired comfort level. Remember, optimizing energy efficiency while maintaining comfort may require finding the right balance for your specific needs. Experimenting with different settings and utilizing additional tools like scheduling and temperature sensors can help you achieve that balance.

Regards,

Zoe