Ice stores Conservation technology that makes use of off-peak refrigeration energy to charge an ice store for release of cooling energy during the day.
ICS Integral collector/storage system. See: Batch heater
Impact Environmentally, the effect on either the environment or people of a speciﬁc action. See also: Environmental impact statement
Impervious surface Hard surface that either prevents or retards the entry of water into the soil, causing water to run off the surface in greater quantities or at an increased rate of ﬂow. Common impervious surfaces include rooftops, walkways, patios, driveways, parking lots, storage areas, concrete or asphalt paving, and gravel roads. High concentrations of impervious surfaces increase the probability of ﬂooding from heavy rains and storms.