ET and SunFall™
Simplest, most accurate, lowest cost
SunFall™ drives ET. On windy days, ET depends on solar radiation (SunFall™) for 85% of its measurements according to the Department of Water Resources of California. DWR says that 10% of their ET is wind. So, on calm days, ET depends on SunFall™ for 90-95% of its measurement.

The chart to the right uses data for Los Angeles CIMIS (California Irrigation Management Information Service) station #78 and our SunFall sensor. It is a little hard to distinguish the lines because they track so closely.

January was unusually warm and dry with frequent winds from the desert. The wind has 2 effects on ET. The most important is that it clears the sky of stagnant air and allows stronger sunlight to reach the ground. Note the matching peaks in ET and SunFall™ when the wind blew in January.

February brought heavy rains of 7" spread over a week. It is immediately after heavy rains that our SunFall readings deviate from ET the most. Note the red SunFall™ spike in the chart under Heavy Rains when after the sky is washed clean. But during and after heavy rains, the rainfall sensor is blocking irrigation, making our combined sensors are the most accurate on-site, real-time tracking of weather and most accurate adjustment of irrigation.

Our Smart Timer™ which includes our SunFall™ and rainfall sensors is the most convenient, simplest, smartest and lowest cost way to save water.

See the Quick Start for the 2 simple programming steps for our smart sprinkler timers. These steps are easy enough for unskilled homeowners and contractors yet powerful enough to please avid gardeners. See the third simple step that we ask them to do to tune the watering.

SFR sensor senses solar radiation and rain
ET Station maintained by CIMIS