In this paper, non parametric Data Envelopment Analysis (DEA) was subjected to the energy data of wheat producers in Punjab state, India, and technical, pure technical and scale efficiencies were calculated for farms both category wise and zone wise. The main objective was to determine the strength of the correlation between non-parametric efficiencies and indices such as energy ratio and specific energy. Results revealed that larger farms had a higher energy ratio and lower specific energy as compared to smaller ones. Frequency distribution of technical efficiency scores revealed that large farms were more consistent on efficiency scores, and the dispersion of technical efficiency was highest on medium farms followed by semi Medium and small farms. The correlation coefficients between energy ratio and each technical, pure and scale efficiency, as well as those between specific energy and each technical, pure and scale efficiency showed that energy ratio and specific energy are not appropriate indices for explaining farm efficiencies in different farm categories and zones.