A large sample of daily electricity consumption and pricing data are available from a pilot study conducted by BC Hydro in British Columbia (Canada) of its residential customers under optional time-varying pricing and remotely-activated load-control devices for the four winter months of November 2007–February 2008. We use those data to estimate the elasticity of substitution σ, defined as the negative of the percentage change in the peak-to-off-peak kW h ratio due to a 1% change in the peak-to-off-peak price ratio. Our estimates of σ characterize residential price responsiveness with and without load control during cold-weather months. While the estimates of σ sans load control are highly statistically significant (α = 0.01), they are less than 0.07. With load control in place, however, these σ estimates more than triple. Finally, we show that time-varying pricing sans load control causes a peak kW h reduction of 2.6% at the 2:1 peak-to-off-peak price ratio to 9.2% at the 12:1 peak-to-off-peak price ratio. Load control raises these reduction estimates to 9.2% and 30.7%.