Have you seen all of the ad’s for home automation products lately? Well, its possible to make the same improvements outside of your home. Today’s irrigation industry has many options to meet the needs of the home/ property owner that is looking to better manage their outside water use. One of the many ways that this can be done is through a “smart” irrigation controller.
At its base, a smart controller uses weather information to determine the amount of water to be applied by a sprinkler system. The weather’s effect upon vegetation (like your landscape) is called EvapoTranspiration (ET). It is calculated by a formula that factors in weather conditions like temperature, humidity, wind speed and rainfall along with soil, slope and plant factors. There are a number of methods that various manufacturers use to do this.
Some, like Hunter’s Solar Sync model, use a simpler (and possibly less accurate) method in which a sensor measures sunlight and temperature and then adjusts the run time of an entire program to a percentage of the run times that have been manually entered by the user. This method relies heavily on the initial input of the user (which is questionable) and only relies on part of that ET equation to approximate the rest.
Other models and manufacturers use an onsite weather station (probably smaller than what you are thinking) to measure several of the contributing factors of ET. Some measure more than others. Some manufacturers also allow “site factors” ie-soil type, plant type, shade, and slope to be entered into the controller. These site factors are then used with the weather data to calculate the amount of water required for each irrigation zone.
There are also controllers that do not use sensors to determine how much water is needed by the landscape. These controllers use either historical or current ET measurements from off-site sources to manage irrigation. Some allow the controller to be located by zip code, others are able to determine their location automatically. Proponents of this technology point out that on site sensors are mechanical and will eventually become inaccurate or cease to operate entirely. Off-site weather stations, like the NOAA’s, are maintained by the US Department of Commerce and used by numerous entities.
The next step in smart controller evolution is the ability to communicate back and forth, wirelessly, with your sprinkler controller. With this technology, in combination with a flow sensor, you can monitor water use, make adjustments, or completely shut down a system remotely. A few manufacturers (like HydroPoint Data Systems) offer these options and as a whole they create huge potential for water savings.
As you might have guessed, this type of technology doesn’t exactly come cheap. In general, the more complex options are more expensive but also more accurate. Manufacturers list the payback period of some of these controllers as between 3 and 36 months depending upon a multitude of factors. When you consider that you’ll be saving water over the life of the unit and saving money from as little as 3 months and onward, its easy to see why folks are making the investment.