EPW Insights
EPW Insights is a free, open-source, fully client-side web platform for exploring and evaluating EnergyPlus Weather (EPW) data. It combines a broad set of visualization modules with advanced thermal comfort, material, and future climate analysis tools, giving researchers, educators, and practitioners a browser-based platform for climate-informed building and urban design decisions.
Project Overview
The application addresses the need for accessible, interactive visualization of weather data, which is important for sustainable building design and urban planning. Since its initial release, EPW Insights has grown into a comprehensive analysis suite, adding a CMIP6-based future climate projection module, outdoor comfort and peak-condition analysis, material thermal mass evaluation, and a set of thermal comfort algorithms verified against ASHRAE 55 reference tables and independent datasets.
Key Features
- Comprehensive Visualizations Annual heatmaps, monthly distributions, hourly averages, wind roses, and sun path diagrams covering temperature, humidity, sky cover, wind, and solar radiation and daylight.
- Comfort & Performance Analysis A psychrometric chart with ASHRAE 55 and ISO 7730 PMV comfort zones, an Outdoor Comfort module (UTCI, SET, MRT), Peak Conditions and Thermal Analysis, and Material Analysis for thermal mass evaluation.
- Future Climate Projection CMIP6/IPCC AR6 morphing to project any EPW file to 2030, 2050, or 2080 under four SSP scenarios, with baseline-versus-morphed comparisons and degree-day shift analysis.
- Comparison Functionality Side-by-side analysis of two EPW files, including a dedicated infographic overview across all key metrics.
- Validated Algorithms & Data Quality Comfort and morphing algorithms verified against ASHRAE 55-2023 tables and independent datasets, plus automatic guards for non-standard EPW files.
- Export Capabilities High-resolution PNG export for charts and CSV export for filtered data tables.
Key Innovation
EPW Insights represents a significant advancement in weather data accessibility for the building performance and urban design communities.
Unlike traditional desktop applications, this web-based tool requires no installation and provides instant access to sophisticated analysis capabilities. Built as an ES module codebase with Vite, it separates computational logic from D3.js-based rendering, keeping the entire pipeline, from EPW parsing to comfort and climate-projection calculations, transparent and reproducible. Core computational modules are covered by unit tests, and the comfort and morphing algorithms have been validated against ASHRAE reference tables and independent external datasets, giving users confidence in the results without leaving the browser.
Technical Implementation
- Frontend Technologies HTML5, CSS3 (Bootstrap 5), JavaScript (ES6+), bundled as an ES module codebase with Vite
- Visualization Library D3.js (v7) for data-driven document manipulation
- Mapping Leaflet.js for interactive location display
- Solar Calculations SunCalc.js for sun path analysis
- Data Processing A custom EPW parser and comfort/climate-projection algorithms, covered by Vitest unit tests
Access & Resources
- Live Application: https://epwinsights.github.io/
- Source Code: Available on GitHub under the GNU Affero General Public License v3.0 (AGPL-3.0)
- The tool supports standard EPW files and includes an Explore Example Climates picker with example datasets across a range of Koppen climate classifications.