What It Is

I was asked by irrigation contractor Vinny Catoggio to test a new irrigation technology product on a recent project of mine.  It’s called the Hunter Solar Sync by Hunter Industries. This device is connected to your Hunter sprinkler controller and will automatically adjust the watering based on changes in the weather.  By using sensors built into a module that sits out in the open (Vinny mounted it on the rain gutter), the device gathers information on the amount of sun and the temperatures we’re getting. The resulting data is called evapotranspiration or ET.  Simply put, this is the rate at which plants and grass use water.  Using this data the device will automatically increase or decrease how long each sprinkler zone will run.

Why This Could Be So Great

I say could be because for both Vinny and I this is a test. He’s setting it up on a few sites (including his own home) to see how the Hunter Solar Sync performs over a period of time and seasonal changes.  I’m going to be visiting my project site with some regularity and will monitor its performance too.

Typically I have the sprinkler controller mounted on the outside vs. in the garage or house.  This helps the irrigation service people because they don’t have to rely on the customer being home. But for me it’s a major advantage in that I can make unscheduled visits to the property and adjust the controller as needed.

Irrigation is a key ingredient to a successful landscape, but to be successful and efficient it must have to components: 1) Proper design, and that’s a topic unto itself and 2) Seasonal & Climatic adjustments during the year. Beyond the obvious that a landscape has different water requirements in April and July and October, conditions such as rainfall, soil type, grades and plant varieties equally play into the formula.  So any device that helps monitor and adjust to any of these variables is a plus in my book, but it has to do it well and consistently.  Maybe the Hunter Solar Sync is such a device.

  • Sharon
    1:32 PM, 9 May 2011

    When was this posted? Has it been in long enough to be evaluated – if so, what is the recomendation?

    • Roger
      10:58 PM, 9 May 2011

      Hi Sharon,
      This post was written about one year ago.

      So this project had the Solar Sync operating through last year’s growing seasons. Generally it worked well. The system universally adjusted each zones’ run-time “down” from 100% depending on conditions (rain, time of year, temp.)

      Vinny Cattogio, our irrigation contractor, will have a better critique. Let me get his thoughts at this point and get back to you in these “comments”.

  • Roger
    2:19 PM, 15 May 2011

    I’m following up on your recent comment asking about recommendations about the Solar Sync after our using it for a year.

    By the way, have you watched these 2 short training videos on the Solar Sync?

    I spoke w/ Vinny Cattogio this past week to get his thoughts.

    Once you’ve programmed the Hunter controller you’re using to the settings that you want for the hottest time of the year, i.e. July & August, you then activate the Solar Sync. The Solar Sync will then automatically modify those “July/August” global settings on the controller based on current weather.

    Note: The only adjustments the Solar Sync makes to the controller are the zone “run time” amounts. The other settings such as “start time” and “days of the week” are not changed in any way.

    One of the settings you must make on the Solar Sync is for the “region” you are in. There are 4 regions to choose from. Here in northern NJ Vinny initially chose region 2, which relates to summer temps averaging 75 – 85 degrees F. He discovered that setting region 2 did not allow for enough water and experimented using region 1 (average summer temps. 65 – 75 degrees F). This turned out to be the better region setting for our northern NJ area.

    The other setting on the Solar Sync that gives you control over watering amounts is what is called the “water multiplier” or “water + or – setting. The default setting is “5” and you can increase or decrease that to have the Solar Sync allow more or less watering.

    This “water multiplier” setting is fine if you want to universally increase or decrease watering run time for all the zones. But what if you just want to change the run time for one zone? (We find we’re making single zone adjustments like this frequently.) To do this you simply go to the particular zone’s run time setting on the controller and adjust the run time up or down. What you must take into consideration is the Solar Sync will take the new amount of time you’ve entered into the zone and apply its percentage calculation as it does for all the other run times.

    Therefore, if you add 10 mins. of additional run time to a zone, and the Solar Sync has the controller operating at 50%, in effect you’ll will only get an additional 5 mins. of run time.

    Knowing these performance characteristics and getting used to how to “tweak” the main controller and the Solar Sync settings is key. Vinny and I really like the Solar Sync and it’s become a standard install on projects.

  • Sharon
    10:53 PM, 15 May 2011

    Thank you for the information- it is really helpful. I have not viewed the videos yet, but that’s a good idea …

  • Vin Papallo
    12:08 PM, 9 June 2011

    Good afternoon Roger.

    The above posted information is very helpful. Thank You.

    We are considering having 3 Solar Sync controllers installed in our condo complex (there 3 separate irrigation controllers for 48 units). I know that Hunter makes a wireless and non-wireless Solar Sync smart controller. I am trying to get an estimated cost for each one, installed. Would you please be able to provide an estimated cost? Our association would like to get an idea of what is a reasonable cost for this service.

    From your information above, it does not appear that the labor work is complex. Also, we have been told that water cost savings (for our usage) would be about $500-$800/year which is about about 5%-8% of our water usage. Do you have information on cost savings in your experience?

    Vin P.

    • Roger
      10:55 PM, 9 June 2011

      Hello Vin,
      I asked Vinny Cattogio, our irrigation adviser, about your situation. He recommends Hunter’s new I-Core controller. It comes out of the box as a 6 station controller, expandable to 42 stations. The plastic outdoor model goes to 30 stations.

      Vinny mentions how the Solar Sync is just one tool or aspect in the effort to conserve water. Equally contributing is the design of the overall system in terms of lawn zones separate from shrub zones, shaded areas zoned together (ditto on sunny areas), slope areas zoned separately too, etc. This is so important in achieving maximum conservation. It’s the combination of a smartly designed system combined with programming capability of the controller and then tools like the Solar Sync that get great results with minimal water usage.

      In terms of general usage the Solar Sync takes the settings and programs you set up for the hottest months of the year (this is operating at 100%) and automatically reduces those amounts as weather and temperatures change. These are some of the average percentage adjustments (from 100%) Vinny has observed after 3 seasons of working with Solar Syncs: During April and May the system operates at 50%, in June approximately 80%, July and August it operates at nearly 100% of your programmed watering schedule. And during Sept. and Oct. 75 to 50% respectively. This is only a guide and will vary from year to year. And remember this is in our Northeast US location.

      FYI: Vinny says in 2009 (a wet season) the Solar Sync adjusted to operating at 80% for one, short period – the rest of the season it stayed at around 50% usage. In 2010 (a dry season) it operated pretty consistently in the 80 -100% range.

      The location for the Solar Sync “sensing equipment” is important. Vinny also recommends the wired model as opposed to the wireless. He doesn’t have enough feedback on the wireless just yet – it’s too new.

      Lastly, Vinny mentioned a town-home complex he worked on where they had 5 Rainbird controllers for 52 zones. He installed two I-Core controllers and two Solar Syncs for about $3,200.00. He said before these upgrades the system would be turned on in early May and it would run every-other-day at, of course, 100% for the entire season. Like he said, “Ridiculous!”

      These are some of Vinny’s final comments: Remember, the Solar Sync has only been out for 3 seasons, so there is not a lot of data on it. Most contractors, for now, do not want to get involved with it because there is a “learning curve” and once in a while it “does some strange things”. If you install one I would recommend you check your controller once a week or two to get a feel for the various percentage changes. Once you understand what you’re doing I think you would be satisfied.

      Hope this helps, Vin.

  • Dino
    11:17 AM, 15 September 2011

    I have not had a good experience with the Solar Sync and find I’m constantly checking my Pro-C to see what adjustments it makes every day which is counter productive to what the unit is supposed to save you from doing. In general I find it lowers the run times far too much. I have placed the device in a location that gets about 8 hours of direct sunlight per day and have tried bumping up the +- adjustment but still find it lowers the % too much. According to a Hunter tech I corresponded with, the unit does not take into consideration nor can it measure how much rain has occured. It simply measures and records the amount of sunlight its receiving. It can’t destiguigh temperature either. As well it makes adjustments on a daily basis (at midnight) so if you are only watering lawns once or twice per week (deep watering) then it the adjustments may be way off in the sense that it has no idea how long or how often you are watering.
    In my opinion a plain rainclic sensor with perhaps a moisture sensor might be the best way to go. I’m very fine with making adjustments 3-4 times per season and know exactly how long my water times will be.
    My installer commented that they have had similar feedback from many of their customers as well.

    • Roger
      9:39 PM, 19 September 2011

      Vinny Cattagio, our irrigation advisor and LA contributor, sent me this advice for your situation:

      If you’re watering your lawn once or twice a week using the deep water method I would suggest increasing your watering times 50%. If the rotary zone was set for 30 or 40 minutes, try 45 to 60 minutes, assuming the sprinkler heads and nozzles are set properly.

      Also, if you have your region set at region 2 change it to region 1. This will maintain a higher watering percentage then region 2.

      Try increasing your watering increment from 5 to 8,9 or 10.

      Remember, the Solar Sync is not the be all – end all device. Customers are mostly concerned with conserving water while maintaining their turf.

      We have found if you are paying for your water, your payback period would only take one season. It has been very successful for many of our systems.

      Good Luck
      (Vinny C.)

  • Eric
    4:31 PM, 11 March 2012

    I have a solar sync wireless and was wondering if you let the computer run your system on a daily basis or a set number of days per week?


    • Roger
      9:17 AM, 12 March 2012

      In the initial setup of the controller I set the particular days, times and durations (per zone) I want the system to run (at 100%) during the season. From that point it is the solar sync’s job to adjust those initial settings (by percentage) based on varying conditions.

      For example, I may have the front yard lawn zones set to run every other day for 30 minutes each. In May we’re having regular rainfall and the temperatures are low. The solar sync should adjust that initial setting down to perhaps 50% so that the zones run for only 15 minutes.

  • Jerry
    10:06 PM, 21 April 2012

    I am gonna punches this but want to make sure if I set it for the hotest months July August. I would set it for 3 times a day fior ten min a zone this sink will adjust it down by 50% do to temp out side or do I have to increase water time when I set this from the get go

    • Roger
      11:14 PM, 21 April 2012

      If I understand your question correctly, you set the controller as you would normally for July and August. That is correct. Based on temperatures the Solar Sync will adjust the “run times” set for each zone by a percentage. However, if you have the controller set to run 3 times/day, it will not eliminate anyone of those scheduled times…only the duration of the run-time (for each zone) you have set per cycle.

  • Mark
    9:06 PM, 12 May 2012

    I have been using the solar sync for over a year and my lawn looks great during the growing season. My question is this. I have beeen told to water deeply and infrequently. If I program my controller for mid-july conditions I will program it to water every 2 days. This seems to be too frequently for every off peak month. I mean I know the solar synce adjust run times based on ET values so it wouldn’t be watering for all that long on those off peak months but the watering interval seems like I would be wasting more water if it is set to water every other day throughout the entire season. Moreover this has confused my water days calculation. Traditional methods of calculating water days required you to know exactly how much water your system was putting down every time it was run. But with this system unless you check the percentage on the controller each water day you have no idea how much water your putting down on any given water day making it impossible to calculate a scheduled number of days between waterings.

    • Roger
      10:42 PM, 13 May 2012

      I showed Vinny Catoggio, our irrigation advisor, your question and concern about the Solar Sync. Here’s his response:

      Remembering that the Solar Sync was designed to reduce excess water use and not the where all and end all to precise turf needs.

      While, what you’re trying to accomplish is commendable, you would need more information than your Solar Sync can provide.

      With more information, such as what type of soil, water distribution per zone and moisture content, only then would you be able to accomplish your goal, to some degree .

      I would suggest you try altering your days to water as well as the watering scale on your solar sync during the off peak months.
      Hope this was useful.

      Mark, I’ve said to Vinny all along that the ultimate irrigation system would be based on soil moisture. There is technology out there that enables you to install moisture sensors in the soil that tell the controller when to water. The challenges are that the system installed would be expensive, and also the sensors would likely fail over time (costly to maintain).

      In the meantime the Solar Sync does a fairly good job within its designed capability. It sounds like you’re pretty familiar with your lawn and its water needs. Go with your intuition and in the off-season adjust the “days to water” like Vinny suggests. For example, go from every 2 days to every 4 days.

      Most people over-water, especially in the off-season months. It’s great the way you’re attentive to your water usage. Be conservative with your watering (especially in the off-season). If you’re as attentive as it seems, it will simply be a matter of increasing the schedule should you see the lawn is not getting enough water.

  • Mark Carroll
    10:54 PM, 15 May 2012

    I have downloaded an ET Estimator Spreadsheet and have added the estimated ET’s to my Water Balance Spreadsheet and determined the estimated days to water based on the predicted evapotranspiration from the turf. This suggested I water on a uneven schedule i.e. not every 2 or 3 or 4 days but on a schedule most closely following the predicted weather patterns . I will use daily ET values available on the web in determining when to water.
    The solar sync will adjust the watering times according to the calcuated ET’s it measures. So I will most likely be watering WHEN and HOW MUCH the turf needs it.

    I really wish Hunter would have gone one step further with the solar sync and would have made it automatically alter the days to water as well as the run times. But I will do this for now on my own based on actual water use by the turf.

    • Roger
      8:33 AM, 16 May 2012

      This is excellent what you’re doing. So through your calculations and information gathering you’re inputting the days the system should run, and then letting the Solar Sync adjust “run time” based on its ET calculations. Nice.

      I know there are more sophisticated systems out there that are automatically doing what you’re doing, and eventually we’ll see this technology become more mainstream.

      Hats off to your dedication and effort to conserve.

  • Jason
    9:00 PM, 30 May 2012

    Thank you for this article and comments. I live in North Jersey and recently installed a solar sync. I originally selected zone 2 and then after your comments I changed to zone 1.

    My questions are:

    What have your experiences with the dry out vent on the Rain Clik? I set it to one open vent and will see how it goes.

    I plan on determining my water output by place 8 containers in each zone and run the zone for 15 minutes and then figure out how much each zone needs to run for 1 inch of water. Any suggestions on placement of those containers for the test?

    Finally what are your watering suggestions for grass, annuals (impatiens) and perrenials?

    • Roger
      2:09 PM, 1 June 2012

      With regard to the Rain Click sensor, we set it so the vents are open all the way. We do this because we’re not monitoring these systems constantly and need to be sure they reactivate within a reasonable time after a rain event. If you’re watching your system closely you could experiment with the adjustment.

      I forwarded your message with regard to the water collecting containers to Vinny Catoggio, our irrigation advisor. His response:

      Set your cups at 15 foot spacing for mist areas, and set them at 30 feet for rotary head areas. Determine your results from there.

      Solar Sync set to region 1 water level 5 will yield the best result for the North Jersey area. You can always up your water level above 5 up to 10. You’ll get approximately 5 to 10% increase with each number depending on the location of the Solar Sync.

      For watering suggestions for grass, annuals and perennials it’s difficult to cover the topic completely in a short response like this. If you download my free report “Landscape Contracting Fundamentals,” there’s an entire section on irrigation. It’s really worth the read and you’ll have a complete understanding of what proper watering is.

  • Eric
    2:26 PM, 9 June 2012

    My solar sync will not let my irrigation system to irrigate after extended period of dryness following precipitation. Is this normal? I have had to resord to using the bypsas switchon the controller or rebooting the solar sync. It appears all the other functions (i.e. adjusting run times, freeze feature and rain shutdown) work fine. My hard wired solar sync is connected in to a PRO-C controler. I have attempted a hard reboot of the contraoler but I seem to have this issue. Please advise.

    • Roger
      6:50 PM, 10 June 2012

      I contacted Vinny Catoggio, our irrigation advisor, and here’s his response:

      Your problem may be with the rain sensor portion of the Solar Sync. Try pushing down the tab on top of the rain sensor and see if you hear a click. If not, and your sure the sensor is dry, then there may be some debri on the micro switch or the switch is defective.

      Open the window on the sensor and visibly check for any foreign matter. If its dry you should hear a click everytime you press it down. Good luck

  • SAMI
    6:54 PM, 10 June 2016

    Three questuins for new installation

    1. So in the final analysis Solar Syncgood or avoid? Need to design for my system
    COsting $200 extra fro SolarSync

    2. The pop up sprays how high should they pop up to?

    3. Should established shrubs be included or not?

    4. Plumbing copper or PVC?

    Thank you for a very informative site! 🙂

    • Roger
      6:13 PM, 11 June 2016

      1. We’ve used the Solar Sync on several jobs and frankly, I’m not a real fan. To be fair, I’m told by others you have to work with it for a while to understand it better. And then, once adjusted properly, it does what it’s designed to do, i.e. modify watering to seasonal/weather changes. For me, I’m OK with just a “rain sensor,” and then adjusting the controller’s schedule (frequency and run-time) as I see the need. I always ask the sprinkler contractor to install the controller on the outside so I can always get to it (for adjustments.)

      2. The pop-up sprays you use and how high you set them depends on the nearby plant material height. You want the head, when it pops up, to clear all vegetation. Usually, after a couple of years, the heads have to be raised, moved or changed as the plantings grow.

      3. You’ll find that once plants establish themselves they rarely need to be watered. This is why our systems are designed with plantings separate from lawn.

      4. Typically plumbing is copper coming out of the house to the backflow device. From there it’s PVC and poly pipe.

      Hope this helps!

  • Hank
    11:39 PM, 22 May 2017

    Hi- I just installed the solar sync this May on my pro-c. I live in Glen Rock, NJ which has sandy soil and plan to have the system run 3x per week. I set the solar sync on region 2, 5 with a max run time of 40 minutes/zone. Last year I was watering 2x/week for 60 minutes/zone during the summer but decided to run the same number of minutes spread out over 3 days.
    1- do you recommend I switch to region 1?
    2- do you recommend I go back to 2 days per week watering and up the max minutes to 60/zone?
    3- I did see the solar sync go to 110% runtime this week when we had two abnormally high temp days of 90+. Is that normal for it to adjust run times over 100%?
    Thanks for your help.

    • Roger
      9:35 PM, 23 May 2017

      If you look back in the comments to my reply to: Sharon on May 5, 2011 you’ll see I cover the region setting issue — and I’m here in northern NJ so it’s applicable to you in Glen Rock, NJ.

      Most of the systems we have out there run 3x a week during the warmer months for the lawn zones. Established planting zones, of course, use considerably less.

      I’m not sure about the solar sync going to 110%. My guess is that will not happen when you switch to region 1 (as I discuss in my comment to Sharon).

  • Byron
    8:34 AM, 6 May 2018

    I live in central Florida. What is the proper regional setting for me?

    • Roger
      9:43 AM, 6 May 2018

      I’m here in the northeast, so I’m not familiar with the best Solar Sync settings for your area.

      It looks like the Solar Sync Manual is suggesting Region 3 for your area. I would start there. In addition to Region setting there are other adjustments you can make. Refer to those “tweaks” starting on page 14 of the manual. It really does take some “tweaking” to get it right for your particular area and property.

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