Our Solar Roof Hot Water System was installed on 28th February 2007.

The main reading of interest is the temperature of the Hot Water in the morning. The "morning" temperature is after the night time cooling of the water in the tank, but also represents our peak personal hot water use time (e.g. morning showers).

We witness that the typical morning temperature is "on average" well above the 120F temperature recommended by the EPA and EnergyStar as a typical heat to tempertaure for Hot Water.  This pie chart shows data in increments of 10F with values less than 120F dedicated to their own slice. We in fact see that around 70% of our morining readings are over 140F, which is a great temperature for our Dishwasher (it is too hot for our Shower without cooling).
Morning Hot Water Temperature

We witness great solar heating performance for our hot water. The following plot shows the percentage of days where our hot water was heated by the sun only (i.e. no supplemental heating). When we planned the system we estimated an average performance of 80% over an entire year, we actually witness a few points above this over the year. In the winter months solar heating is around 50%.
Hot water days

The plot below is the distribution of the temperatures in our Solar Hot Water System.

Plot of data

Solar Hot Water
The same data can be seen in the following animated GIF. This shows a plot of the readings in the Morning, at Noon and in the Afternoon along with the corresponding "box and whisker plot". Every 2 seconds the image will change, the fourth image being the combination of all the plots.
Solar Hot Water Animation
We are collecting all our solar data.
Email: darrell AT nearto.us
Web: http://www.nearto.us/