UI-IDL Climate Design Resources - 1st & 2nd Generation Tool sets

The Idaho Power Company funded the University of Idaho Integrated Design Lab (UI-IDL) to produce a series of climate design resources to help assist in the conceptual and early design of passive strategies. Through their support, the UI-IDL has developed two generations of spreadsheet calculators that are capable of analyzing building loads and energy consumption impacts of a range of different design strategies over three reference cities. You can download the tools and both the 1st and 2nd generation research reports at the bottom of this webpage. The reports provide insight into the methodology of the research used to develop the tools as well as information on how to use them most effectively.

Currently, there are seven different calculation spreadsheets that span across two different generations of tool development:

  • Heat Gain Calculations
  • Cross Ventilation
  • Stack Ventilation
  • Night Ventilation Thermal Mass

  • Balance Point Calculation
  • Passive Solar
  • Earth Tube
  • Each spreadsheet contains multiple tabs and a step-by-step process that directs the user to define the critical baseline and performance parameters of the building. These factors are linked to pre-defined equations within the spreadsheet that automatically provide the peak cooling loads, cooling capacities, and describe other critical design criteria. Charts, line graphs, and other forms of graphic information also automatically populate the workspace to provide rich visual feedback to the user. The spreadsheets also contain a reference tab that consolidates a myriad of textbook, code, and other sources needed to complete the step-by-step instructions. Additionally, a variety of weather data, including hourly information from TMY weather files, are embedded into the calculations based upon three different reference cities within the Idaho Power Company service territory. Once each tab is filled out, the results pages of the spreadsheets contains all of the important outputs needed to evaluate how much the passive design measure can contribute to the peak loads or energy savings of the building. Changes to the building parameters are instantaneous, making the Climate Tools Package an ideal instrument used to explore different design iterations and how they might facilitate passive design strategies.


    The ultimate goal of the Climate Tools Package is to reduce the loads and energy consumption of a building through passive design measures. This happens mainly by embedding, early in the design process, the analysis of the performance capabilities of different passive cooling and heating strategies. Once a performance capacity is calculated and compared against peak loads of a building, a qualitative decision can be made whether or not to pursue more detailed analysis. If certain passive strategies are proven to meet some or all of the peak load, this may warrant further development. Potential next steps could involve more advanced analysis such as building simulation to quantify annual energy savings based on actual weather data.

    Boise set
    Pocatello set
    McCall set
    Billings, MT set

    Click here to see the 1st Generation CDR Tools Report to Idaho Power (pdf)

    Click here to see the 2nd Generation CDR Tools Report to Idaho Power (pdf)