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TEST — Thermal Energy Savings Tabulator

An hour-by-hour building load & energy model for schematic design. TEST reconstructs the University of Idaho IDL spreadsheet as a browser tool — sizing peak heating and cooling, estimating annual energy and cost across HVAC systems, and quantifying how passive strategies trim the load, all from a single weather file using the ASHRAE Radiant Time Series method.

Launch the tool → Back to CODEX tools

What it does

Six analyses from one model run, scaled to early-design precision rather than construction-document detail.

▲Hourly load engine8,760-hour Radiant Time Series simulation with separate solar and non-solar response factors, a floating-deadband zone temperature, and coincident peak heating & cooling.
☀Solar heat gainFull solar geometry — declination, equation of time, hour angle and per-orientation incidence — driving glazing gains by surface, hour, and season.
⚙HVAC energy & costBaseline-versus-proposed comparison across ASHRAE system types, with end-use breakdown, EUI, and annual energy-cost savings.
❄Passive design potentialBalance-point temperature, cross- and stack-ventilation hours, night-flush mass storage, and Balcomb passive-solar savings.
☷Idaho climate library21 Idaho cities in five regions with TMYx weather fetch, plus drag-and-drop EPW upload for any site worldwide.
📊Visual outputAnnual load signature, monthly energy, design-day profiles, peak-component breakdown, and an EUI comparison — all rendered in-browser.

Validated against the source workbook

The engine was reconstructed cell-for-cell from the IDL TEST workbook and checked against its cached results on a real Boise TMYx year (default office model).

±2.3%Peak cooling vs. workbook
±3.4%Peak heating vs. workbook
±0.3%Peak coincident solar gain
±3%Annual heating & cooling energy

Method

TEST applies the ASHRAE Radiant Time Series (RTS) method: conductive, solar, and internal gains are split into convective and radiant fractions, the radiant share is delayed through 24-hour response factors selected by construction mass, and the hourly result is balanced against a floating zone temperature between the heating and cooling set points. Outdoor-air loads are altitude-corrected; infiltration and mechanical ventilation switch with occupancy. The approach follows the schematic-design analysis tradition of Brown & DeKay’s Sun, Wind & Light, restoring a graphic, fast-feedback workflow to early design.

Scope & caveats. Single-zone, one-dimensional steady-state envelope. The office schedule is a fixed weekly profile (the source workbook uses a daylight-responsive lighting schedule, so absolute lighting energy differs by a few percent). Other building types use ASHRAE-style operating-window profiles. HVAC energy uses a delivered-energy COP method rather than full part-load curves. Intended for schematic-phase comparison, not code compliance or final equipment selection.

How to use

  1. Pick an Idaho city or upload an EPW weather file.
  2. Set building use, floor area, and geometry — sensible defaults load automatically.
  3. Adjust envelope, glazing, internal gains, and HVAC systems as needed.
  4. Run the hourly simulation and read the peaks, energy, cost, and passive potential.
TEST — Thermal Energy Savings Tabulator. Part of CODEX, the Climate-Oriented Design Explorer suite developed at the University of Idaho Integrated Design Lab. Methodology after J. Brown & M. DeKay, Sun, Wind & Light: Architectural Design Strategies, 3rd ed., and the ASHRAE Radiant Time Series method. Ported from the IDL TEST workbook. For schematic-design use.
LEGACY_TEST.xlsx