RED Calc Free

v1.0, Legacy Tool

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Save your calculations to RED Cloud ♦ Organize your work in folders ♦ Save time with templates ♦ Print and save PDF reports ♦ Customizable report headers and footers ♦ Preferential support ♦ Multi-tab/window syncing ♦ Fully functional offline mode ♦ No ads

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You can use RED Calc Pro for 30 days free!

  • Sign up for a monthly or yearly subscription. To do so, you must use your credit card, which will not be charged until the 30-day free trial period ends. 
  • If you think RED Calc Pro is not for you, you may cancel your subscription during the free-trial period, no charge, no fees.

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Try RED Calc Pro for free

Free Tool Summary: Calculate up to eight air leakage metrics, including ACH50, equivalent leakage area (EqLA), effective leakage area (ELA), specific leakage area (SLA), and more. Determine if your building complies with the International Energy Conservation Code or Energy Star Qualified Homes requirements for ACH50 or the Washington State requirement for SLA. See Tool Guide. Click on any input or result label for help. By using this tool (application) you agree to the Terms of Use.

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This legacy tool is NOT optimized for mobile devices. Stay tuned for the mobile-optimized version.