What Are These So-Called “ET” Controllers?

Posted on: January 13th, 2012 by NickMillward Posted in Uncategorized

http://www.youtube.com/watch?v=n4fyXWcfAb8

This is the very same controller and weather station we install here at City Rain Inc. We’ve been using this product since around 2007. There were some issues with the first batch of weather monitors we installed. They worked for about 3 years and then just stopped working. Fortunately Weathermatic has made improvements and gave us replacements hassle free.

What is ET? ET is short for evapotranspiration- which is a wonderful portmanteau (man I love that word!) of evaporation and transpiration. So if you remember those terms from grade school, we’re talking about the water that returns to heaven either through being inhaled and exhaled through a plant, or just drying out from bark, mulch, soil, sidewalks, etc.  ‘ET controllers’ are designed to replace just the amount of water lost to ET.  (Gen Xers please refrain from any phone home jokes. )They do this  by calculating real time weather data along with the soil type, plant type, sprinkler type, slope angle, and latitude. The way this particular controller works is, you decide which days of the week and what time of day to water- the controller decides for how long, or if at all, per each zone. When I say zone I refer to a section of landscape watered by a single station on the controller.

Watching this video you get the sense that after setting this up  you can forget all your cares and spend your free time in the yard sipping wine and admiring the peonies. Not quite. First, you should be confident your sprinkler guy or gal is savvy enough about the programming and placement of the monitor. Secondly, you need to be vigilant throughout the first season you use a ‘smart’ controller. The margins of error can be big at first. You are dialing in a bunch of factors to YOUR specific yard. The soil may not be as sandy or loamy as you think, or some areas may be shadier or sunnier than you realize, etc. Have your sprinkler person check and review the system mid-season.

For those of you in the Seattle area that have crappy 20th century era controllers, you are eligible for up to around $275 in rebates for upgrading to an ET controller. Visit the Saving Water Partnership website for more info, then call me at 206.778.5752 or email nick@cityraininc.com

UPDATE FEB. 2013: SORRY SEATTLE AREA SINGLE FAMILY HOMEOWNERS- NO DICE- REBATES NOW ONLY APPLY TO MULTI-FAMILY DWELLINGS AND BIGGER SQUARE FOOTAGE COMMERCIAL LANDSCAPES. you had a good run. (sad face)