Yes an iStore can be installed inside but the iStore requires a minimum of 120 cubic meters of natural ventilation to operate efficiently. An example would be an area of 8.0m x 6.3m x 2.4m (a large double garage or open space under a home). External installation is the preferred method to capture the warm ambient air temperature but note the air discharged will always be cold. If unit is being installed internally, provision for fresh air to be introduced shall be provided 450(270L) / 700(180L) m3/h minimum requirement