Nest Thermostat Data Archive and Nest Home Report

[cunninghamb017]

Hi, I am working with a Nest Data Archive from Oct 2022. 

There are discrepancies in the data. For example, my Nest Home Report email for October 2022 shows 51 hours usage However, if I add up all of the cycles duration, for each day in the summary file (2022-10-summary.json) this comes to 298413s or 82.89 hours. 

Why is there this difference? 

Location of  file in archive:

NEST_DATA-20221023T132420Z-001\NEST_DATA\Nest\thermostats\09AA01AC45180EWJ\2022\10\2022-10-summary.json

[alejandom]

Hi @cunninghamb017,

I hope you are well and I would like to thank you for posting on our community page, on the other hand I apologize for the inconvenience that you are having. Let me tell you some troubleshooting steps that you can try to fix the problem.

1. Reporting Discrepancies:

Rounding Differences: The Nest Home Report email might round usage time to the nearest hour, while the data archive reflects the exact duration in seconds. This could explain the difference between 51 hours and 82.89 hours.

Report Focus: The Nest Home Report email might focus on specific metrics like "active time" when the thermostat was actively heating or cooling, while the data archive includes all cycles, even those for maintaining temperature or in idle states.

2. Data Archive Interpretation:

• Cycles vs. Usage: The "cycles duration" in the summary file might not directly translate to user-perceived "usage." It could include short cycles for adjustments or maintaining temperature, which wouldn't necessarily reflect actual heating or cooling time.

Check the Data Archive:

• Look for additional details within the data archive files (like cycle types, target temperatures, etc.) that might shed light on the discrepancies.

If for some reason you still have more concerns don't hesitate to let us Know.

Regards,

Mario. 

[cunninghamb017]

Hi Mario,

Thanks for your reply.

I am interested in analysing the data contained in the export, specifically "active time" when the thermostat was actively heating or cooling.

What I find useful in the Nest app in the information contained in the history view, where you can get access to usage details for the last ten days. You can see how long the thermostat was heating (in my case) throughout the day. This is the really useful information.

I would like to be able to generate this, using the data export, for every day and not just the last ten. Is that possible?

Would you have a data dictionary to hand that would provide information as to how I could interpret the data export? For example, a definition of cycle type, event types and so on? This would be very useful. 

I have no problem analysing the data myself, working with the JSON and CSV files etc to build up a picture of my energy usage, I just can't at the moment without information on what the data means.

If it is any useful, my Nest account hasn't been migrated over to Google. I'm not sure if this would be a factor in your response.

Regards,

Brian

[alejandom]

Hi @cunninghamb017,

I can definitely help you with that, Brian. Analyzing the Nest data export for "active time" is possible, but it requires some data manipulation. Here's a breakdown to get you started:

Extracting Active Time from Nest Data Export:

Data Format: Your Nest data export likely comes in JSON or CSV format. Both can be analyzed to calculate "active time."

Key Fields: Focus on these fields within the data:

• cycle_type: This indicates the cycle type (e.g., "heat," "cool," "idle").
• start_time: This represents the timestamp (usually UTC) when the cycle began.
• end_time: This represents the timestamp (usually UTC) when the cycle ended.

Identifying Heating/Cooling Cycles: Filter the data to include only cycles where "cycle_type" is either "heat" or "cool."

Calculating Active Time per Cycle: For each relevant cycle, subtract the "start_time" from the "end_time." This will give you the duration of each heating or cooling cycle in seconds.

Total Active Time per Day: Add up the durations of all heating and cooling cycles for a specific day to determine the total "active time" for heating or cooling.

Missing Data Dictionary:

Unfortunately, Google doesn't provide an official data dictionary for the Nest export. However, there are workarounds:

• Community Forums: Search the Google Nest Community forums (https://goo.gle/3euXaDe) for discussions related to Nest data export analysis. Users might share insights or tools they've developed to work with the data. Look for threads where users discuss the meaning of specific data fields within the export.
• GitHub Repositories: Developers on platforms like GitHub (https://goo.gle/3W8lePL) have created tools and scripts to analyze Nest data exports. These tools often include comments or documentation that explain the meaning of specific data fields within the export. Search for projects related to Nest data analysis and see if any provide explanations for the data format.

If you have another question, don't hesitate to let us know.

Regards,

Mario.

[cunninghamb017]

Hi,

I have twice requested a data extract and both times the have come back with errors. What happened?

Regards,

Brian

[alejandom]

Hi @cunninghamb017,

I'm really sorry that you are having this type of situation with your Thermostat. I’ll need additional information from you that would be best shared privately. I’m sharing a link to a form for you to fill out so we can look into this further. Please let me know once you’re done.

Regards,

Mario.