The Rosenfeld Effect is the empirical fact that electricity use per capita in California (CA) has been almost flat from 1973 to 2006, whereas use in the US has gone up 50%. The effect is attributed to energy efficiency, a cause pioneered by Arthur H. Rosenfeld.

A conference in 2006 at UC Berkeley was dedicated to the Rosenfeld Effect.

It is often associated with the following two graphs:

1. Energy per capita vs time, comparing the US and California
2. Estimated energy savings in California from efficiency standards and programs

The first graph is Figure 1 of the 2007 California Integrated Energy Policy Report and is sometimes referred to as the Rosenfeld Curve. The second is widely used in powerpoint presentations.