Nest Web Energy History Overlay

WHAT IT DOES

This tool analyzes your Nest energy history and presents it in a clear, actionable dashboard. It scans Nest energy pages for daily usage data—date, heating hours, cooling hours, total energy usage, and outside temperature. The panel displays a bar chart showing usage trends over time with color coding (yellow for heating, blue for cooling, purple for mixed). Summary statistics show average usage, total heating/cooling split, total estimated cost, and usage range. Days with unusually high or low usage are highlighted with colored borders. A trend indicator shows whether usage is increasing, decreasing, or stable over time. Estimated cost is calculated based on user-defined energy rates.

WHERE IT RUNS

The script activates on Nest pages (nest.com), including energy history pages, usage reports, and thermostat history views. It automatically detects energy data using multiple extraction strategies that work across different Nest layouts. The panel appears as a draggable overlay that stays accessible as you review your energy history.

HOW TO USE

Navigate to your Nest energy history page. The panel will appear showing a chart and summary of your energy usage. Set the "Rate" input to match your energy cost per hour (default $0.15). Choose the "Cost" method—Fixed (simple rate) or Tiered (discount for higher usage). Toggle "Temp on/off" to show or hide outside temperature data. Set the "Refresh (s)" input to control how often the script checks for updates (default 60 seconds). The "Refresh" button manually updates the data. The chart shows the last 21 days of usage, and the list shows the last 30 days with details. The trend indicator shows whether usage is increasing or decreasing.

THE TECHNICAL MECHANISM

The script employs a multi-strategy DOM extraction approach for Nest's energy history interface. It first attempts structured selectors targeting known class names like .day-item, .history-item, and .energy-item, then falls back to heuristic detection of day containers based on content patterns including "heating", "cooling", and temperature indicators. Dates are extracted from date patterns with support for multiple formats. Heating and cooling hours are extracted using regex patterns for "heating" and "cooling" followed by hour values. Outside temperature is extracted from patterns with degree symbols. Total energy usage is calculated as the sum of heating and cooling hours when not directly available. Cost calculation supports both fixed-rate and tiered pricing models. The trend indicator compares the average usage of the last 7 days against the previous period. The auto-refresh uses setInterval with a user-configurable interval, and a MutationObserver watches for page updates. All settings are persisted using GM_setValue.

THE PANEL

The panel is fully draggable by its header and remembers its position on the page across sessions. It can be collapsed to a small bubble using the minimize button, then restored by clicking the bubble. The panel resizes automatically to fit its content and can be closed with the Escape key or by clicking the close button. The panel's position and state persist globally, so it returns to the same location on subsequent visits.

PLEASE NOTE

Requires the free BotGentz extension to run. Nest may update its site structure, which could affect the script's ability to detect energy data — updates will be released as needed. All energy data is read from the page and displayed locally; nothing is transmitted externally. The script reads data from the visible page and does not access any data beyond what is visibly presented. The script does not modify your Nest account or thermostat settings. Cost estimates are based on the rates you provide and are for informational purposes only. Actual energy costs may vary. This tool is for informational purposes only and is not affiliated with Nest.