Authors' headline is the annual price elasticity of -.58 (and annual income elasticity .15), stated in the abstract/results and carried into Table 4 comparison || 'our estimated annual price elasticity is -.58' (p.317) and 'our price elasticity estimate of -.58 is roughly midway...' (p.318)
Parti, M. and C. Parti (1980): “The Total and Appliance-Specific Conditional Demand for Electricity in the Household Sector.” The Bell Journal of Economics 11(1), 309-321