Automatic Savings from Irrigation Devices

By: Greg Plantamura, Grant Worker

If your home uses an automatic irrigation system, these devices can help you save energy, water and money–and keep your yard looking greener.



Rain sensors, the simplest rain shut-off device, are designed to bypass a scheduled event from an automatic irrigation system timer after a specific amount of rainfall has occurred. They are small and inexpensive devices that are wired to the irrigation system timer. They can result in a 34% savings during normal/wet weather conditions and 15% savings during dry weather conditions.

Soil moisture controllers are designed to bypass a scheduled event from an automatic irrigation system timer if the soil water content is above a certain threshold, defined and set by the user. The sensor, buried within the turf grass or landscape root zone, checks the soil water content. Savings could provide a payback in one to two years and result in 69 to 92% savings during normal/wet weather.

ET (Weather-based) controllers schedule irrigation based on on-site weather data (Stand-Alone) or a signal from a local, publicly available weather station (Signal-Based). ET controllers work differently depending on the manufacturer but typically can be programmed with site-specific conditions such as soil type, plant type, sprinkler type, sun and shade, etc. Yearly signal fees may be required.

All of these devices can be set up to conform to day-of-week watering restrictions.

Resources:

Energy Efficient Irrigation Systems