The goal of this paper is to assess the optimal choice of a household in California, United States, in terms of their decision if and when to undertake a certain investment in a residential scale, grid connected, solar photo-voltaic system, in order to obtain savings in their monthly expenditures in electricity. This irreversible option is then defined, mainly, by the initial cost of the solar PV system. For this purpose, Real Options Analysis is deployed to assess this investment opportunity for the household. This approach allows determining not only whether the investments should be undertaken or not, but also the optimal timing to do so. Results show it is optimal for a Californian household to invest in a photo-voltaic system, however some delay might be advised depending on the energy production factor of specific areas, and the expected useful life of the equipment. Furthermore, government intervention influencing subsidies and energy prices has a bigger effect in the length such delays and should be avoided whenever possible.