RED Calc Pro

September 9, 2020 –

Launched new versions of most RED Calc Pro tools, now version “v1.0.2” (Version: 2020-09-10T00:29). These updates are mostly “under the hood” so users will not detect them, but they make the tools more resilient.


  • Includes the new Units Calculator tool with several new units added to the math-engine.
  • Added tsp, tbsp, link, hand, rod, chain, furlong, hectare, ct, grain, ltyr, parsec, ozv, nmi, and kn (knots) units to math engine, these are part of the new Units Calculator.
  • Moved the tool guide urls from the application code to the tool descriptors.
  • Math on-the-fly inputs now display their calculation result based on 10 significant figures with trailing zeros removed.
  • Fixed the DHW Per Use tool.
  • Links in Markdown text will now open in a new tab.
  • Changed the definition of “yr” in the math engine to be 365.25 days.
  • The tool descriptor version is now shown at the bottom of the tool view.
  • The tool guide urls for the Electrical Usage tool and all those alphabetically after it were broken and have now been fixed.
  • The tool guide url for the Notes tool to /red-calc-pro-manual/#notes.
  • The tool guide url for Settings to /red-calc-pro-manual/#settings.
  • The “Adjusted leakage” result in the Air Leakage Metrics tool was not set to display to the nearest CFM. This is now fixed.

January 17, 2020 – 

  • Launched Pitot Tube Airflow tool with corresponding Tool Guide.
  • Launched Units Calculator tool with corresponding Tool Guide.
  • Updates to Math on-the-fly regarding mathematical rounding.
  • Addition of tool versioning notation.

November 18, 2019 – 

  • Launched new RED Calc Pro tool, ASHRAE 62.2-2019. This tool performs a ventilation rate calculation for compliance with ASHRAE standard 62.2-2019.
  • Found the missing “X” for the upper-right corner of popup help boxes. Clicking the “X” dismisses the box.
  • Added a lock icon that fades in and back out if you try to click into a disabled input box. This is a further indication, or reminder,  that a tool is locked.

October 15, 2019 – 

  • The official launch of new Residential Energy Dynamics website ( RED Calc Free tools are available on this website, as is access to RED Calc Pro for subscribers.
  • The official launch of RED Calc Pro web application with 17 tools, version 1.0.0. This web application is available to subscribers only.

September 25, 2019 – 

  • Soft launch of new Residential Energy Dynamics website ( RED Calc Free tools are available on this website, as is access to RED Calc Pro for subscribers.
  • Soft launch of RED Calc Pro web application with 17 tools, version 1.0.0. This web application is available to subscribers only.

April 2019 – Beta testing, phase 2, of RED Calc Pro begin. New features include:

  • Fully functional offline mode
  • Notes tool for folders and tools
  • Markdown-enabled report forms
  • Enhanced tool reports format
  • Tool and folder locking for data protection
  • Multi-tab/window syncing

January 2018 – Beta testing of RED Calc Pro begins of new mobile-first version. Enhanced features include:

  • Autosave to RED Cloud
  • Folder and template creation
  • Tool reports
  • Enhanced error reporting
  • Incremental stepping of input values
  • Detailed results info

RED Calc Free

September 25, 2019Soft launch of new Residential Energy Dynamics website RED Calc Free tools are available on this website. RED Calc Free tools may also be accessed from the legacy website

November 27, 2018 – Sent our newsletter featuring the Zone Pressure Diagnostics tool, specifically covering methods of reducing the uncertainties.

July 6, 2016 – Updated some of the terminology in the ASHRAE 62.2-2016 tool. Changed term “whole dwelling” to “dwelling unit” to more closely correspond with the terminology in the 62.2-2016 standard.

March 8, 2016 – Posted the ASHRAE 62.2-2016 Ventilation tool and the companion User Guide to the RED websiteThe tool is available before the 62.2-2016 is published! This new ASHRAE Standard now addresses dwellings in high-rise multifamily buildings.

August 3, 2015 – In the ASHRAE 62.2-2013 Ventilation tool, the ASHRAE 62.2-2010 Ventilationtool, and the ASHRAE 62.2 California tool, changed the input label “Living area” to “Floor area” to correspond with the 62.2 standard terminology. Made corresponding changes in the relevant User Guides. Additionally, in the ASHRAE 62.2-2013 Ventilation tool, changed the pop-up help text for the “Floor area” input label to reflect Addendum a to ASHRAE 62.2-2013. Floor area is now based on ANSI Standard Z765.

May 14, 2015 – Added the flow units “m3/hr” to all airflow inputs and results in all tools (thanks to Stefanie Rolfsmeirer in Germany); fixed misspelled “September” in date range input of the Weather Station Data tool; changed the discharge coefficient used in the Box Airflow tool from 0.6 to 0.611 (thanks to Colin Genge, President of  Retrotec).

December 11, 2014 – Added Google AdSense ads to tool and User Guide pages. 

December 8, 2014 – Sent out 15th newsletter announcing the launch of the Moisture Metrics tool

November 26, 2014 – Launched new Moisture Metrics tool, the first tool in the Moisture category.

October 27, 2014 – Sent out 14th newsletter announcing the addition of the “Whole-Building Leakage Rate Solver” section to the ASHRAE 62.2-2013 tool.

October 26, 2014 – Launched the “Whole-Building Leakage Rate Solver” section, a requested addition to the ASHRAE 62.2-2013 tool.

September 15, 2014 – Sent out 13th newsletter announcing the successful use of the RED Zone Pressure Diagnostics tool with the Vermont low-income weatherization program.

August 4, 2014 – Sent out 12th newsletter announcing video tutorials for the RED ASHRAE 62.2-2013 tool.

July 20, 2014 – Updated the Pitot Tube Airflow tool and added 66 Canadian weather station locations to Advanced Infiltration tool and Weather Station Data tools.

June 25, 2014 – Sent out 11th newsletter announcing the new RED video “Controlling Airflow in Existing Dwellings”.

April 15, 2014 – Sent out 10th newsletter featuring the ASHRAE 62.2 California tool.

April 15, 2014 – Released the ASHRAE 62.2 California tool.

April 14. 2014 – Updated the Zone Pressure Diagnostics (ZPD) with drop-down menu choice of house-wrt-zone and house-wrt-outdoors. Also added a result: “Percent of whole-house leakage passing through the zone = xx%”.

April 7, 2014 – Updated Advanced Infiltration tool to include a choice between quadrature and the 0.5 rule for the method of combining ventilation and infiltration.

March 25, 2014 – Sent out 9th newsletter featuring the Zone Pressure Diagnostics (ZPD) tool.

March 3, 2014 – Launched “Zone Pressure Diagnostics” RED Calc Free tool.

February 3, 2014 – Sent out 8th newsletter, featuring the Air Leakage Metrics tool.

December 9, 2013 – Sent out 7th newsletter, featuring the updated Advanced Infiltration tool, now with balanced and unbalanced ventilation integrated into the tool.

September 30, 2013 – Sent out 6th newsletter, featuring five new domestic hot water (DHW) tools added to the Systems Comparison tool. This new DHW tools included Average Daily Usage,  First Hour Rating, Instantaneous Sizing, Volume per Use, and Water Flow Rate. 

September 3, 2013 – Sent out 5th newsletter, featuring the Design Infiltration and the Advanced Infiltration tools. The Advanced Infiltration tool is, by far, the most complex RED Calc Free tool so far.

July 29th, 2013 – Sent out 4th newsletter, featuring the DHW Systems Comparison tool. This was the first RED Calc Free tool to include an interactive bar chart.

June 17, 2013 – Sent out 3rd newsletter, featuring the Weather Station Data (TMY) tool. This was the first RED Calc Free tool to include an interactive line chart and Google map.

May 6, 2013 – Sent out 2nd newsletter, featuring the ASHRAE 62.2-2013 tool.

April 26, 2013 – Launched “ASHRAE 62.2-2013” RED Calc Free tool.

April 16, 2013 – Sent out 1st newsletter, announcing the Insulation and ventilation tool packages. Featured tool was ASHRAE 62.2-2-10.

April 5, 2013 – Launched new Insulation Tool package, including dense-pack insulation, loose-fill insulation, surface heat transfer, infrared R-value, and parallel-path equivalent R-value.