The Certispec automated sizing program is the best and quickest way to spec Ruud Commercial Water Heaters. This software is free from Ruud Water Heating. It’s the only sizing tool you’ll ever need for a tank style water heater.

Please read and print this important information before downloading and installing

Certispec (1.5 mb file)

When you click the Download link below, the program will prompt you to save CertiSpec3Setup.exe to disk.

  • System Requirements:
  • Windows 95/98 or NT 4.X
  • Pentium 90 or higher required
  • 16MB RAM (32MB Recommended)
  • Disk Space: 4-6MB estimated
  • Internet Connection Required for email and Upgrade Download(s)
  • 800 X 600 display resolution
  1. Select download location and click save.
  2. Locate and double click the CertiSpec3Setup.exe file.
  3. Follow the instructions on the screen.
  4. Register and Enjoy your free Certispec software from Rheem!
Download Certispec