Solar hot water heating can be found in every county around the globe. Asia leads in the number of solar water heaters for domestic use but Europe is a close second. In fact countries such as Germany and Israel have been using solar hot water for decades. In fact solar water heating in German is so popular that all new builds both residential and commercial require a solar heating to be incorporated into the heating design.
In North America Hawaii leads in domestic solar water heating because of both the incentives and cost of electricity and California with its aggressive green energy plan is a close second. Canada despite having twice the solar energy as Germany, is far down the list in most part due to lack of a clearly defined green energy plan. However with the success of the Ontario FIT program, Canada may soon see a change in its green energy plan.
Solar water heating is the easiest and most affordable means of going green. Compared to Solar PV, an average household can retrofit their existing water heater to solar water heater for under $3500. A complete solar home heating system can be installed for a few dollars more.