Rachio Iro Smart Sprinkler Controller: Will it save money?

Ever since we moved into our house several years ago, I've been frustrated by the unnecessary complexity of our sprinkler controller.  "Smart" sprinkler controllers have been on the market for a while, but I was put off by the cost.  However, the Rachio Iro (1st Gen, 16 zone) went on sale for $150 (here) as inventory was cleared for the 2nd Gen model, I finally pulled the trigger.



Why Iro?

Simply put, cost.  Several vendors make products with good reviews, and I think they all would have worked for me.  I like the design philosophy, principally cloud independence, of the RainMachine (http://www.rainmachine.com/) better, but my goal (or justification?) for purchasing this setup was to recoup my upfront cost in water savings.  At over $100 cheaper (with this sale), the Iro seemed like the better bet.

First Impressions

It is awesome.  Installation and setup were a breeze.  We've had a bunch of rain during its first two weeks of operation and the rain delay feature has already triggered three times.  Once because it had rained overnight before the sprinkler was set to go off, once because rain was forecast for later in the day, and once because it had rained a lot the previous week.  I think all three were good decisions, and my old system (combination of rain gauge and manual interference) would have missed at least one of those and maybe all three.

Will It Save Money?
I pulled my old water use history, but my water utility only provides two years of history.  Furthermore, we added automated watering for our vegetable garden last year (and had a hose break that caused the usage spike in Sept. 2015).  So, there's not enough data to average-out very noisy data, but regardless, I've plotted the available history and will try to estimate the savings.