Fall 15 DST

Intermatic is here to help you Fall Back with Tech Tips!

Whether you are a distributor, customer or homeowner we have created easy-to-understand time change and installation product guides.

Tip #1 - It is important to understand the difference between Astronomic and Daylight Saving Time. Here is a brief definition for each:

  • Astronomic timing, also known as “Astro” or “Dusk to Dawn” timing, automatically adjusts ON/OFF times with seasonal changes in daylight length. Astronomic timing is typically used to conserve energy. The timer uses both an approximate Latitude Zone (distance from the Equator) and the calendar day-of-year to calculate the Sunrise and Sunset times. Once set properly for a given location, the timer automatically adjusts as needed.
  • Daylight saving time is the practice of advancing clocks during summer months (that feature more daylight) so that people get up earlier in the morning and experience more daylight in the evening.

Tip #2 - It is important to remember if your Intermatic timer offers the DST feature and was manufactured prior to January 1, 2007 you will probably have to manually change the time of day.  Listed below is the series of timers we offer that have the DST feature included along with the date codes.

Model/Series Date Code
DT27C 01B
EI600C All
EJ500C 37A
ET8000 37A
ET70000 45A
ST01C All

Tip #3 - Not wanting to sort through the entire manual to figure out how to change the time? Here are some quick guides to assist you.

Quick Time Change Guides:





Easy Installation Guides:






Tip #4 - If there are still questions, call Tech Services at 815-675-7000 or email technicalservices@intermatic.com.

Contractor Checklist

Download the Daylight Saving Time Infographic


In-Wall Timers Plug-In Timers Electronic Controls
ET1100 ET1700 ET8000 ET2100 ET2700 ET2800 ET90000
  Circuits 1, 2 1, 2 1, 2, 4 1, 2, 4 1, 2, 4 1, 2, 4 1, 2, 4, 8, 12, 16
  USB No No No Yes Yes Yes Yes
  Holidays No No No Yes Yes Yes Yes
  Ethernet No No No No No No Yes
  LED Yes Yes Yes Yes Yes Yes Yes
  Supercapacitor No No No Yes Yes Yes Yes
  *Title 20 No No No Yes Yes Yes Yes
  Astronomic No No Yes No No Yes Yes
  External Override No No No No No No Yes
  PC App No No No No No No Yes 

*Title 20 for commercial use