Appropriate demand response controls allow building operators to reduce the total cost of energy by automating the response of a building to changes in electricity rates. Demand response is an increasingly important function as distributed energy resources become more common, as customers have access to time-of-use electricity rates, and incentive programs are designed to encourage customers to reduce energy during peak demand. Demand response occurs on a range of timescales from seconds to seasons and represents any demand change in response to grid or economic needs. In addition to current time-of-use electricity rates, in the future utilities will likely connect electricity costs to high-frequency fluctuations in supply and demand for electricity.