Energy consumption in buildings, both residential and commercial, accounts
for approximately 40% of all energy usage in the U.S., and similar numbers are
being reported from countries around the world. This significant amount of
energy is used to maintain a comfortable, secure, and productive environment
for the occupants. So, it is crucial that the energy consumption in buildings
must be optimized, all the while maintaining satisfactory levels of occupant
comfort, health, and safety. Recently, Machine Learning has been proven to be
an invaluable tool in deriving important insights from data and optimizing
various systems. In this work, we review the ways in which machine learning has
been leveraged to make buildings smart and energy-efficient. For the
convenience of readers, we provide a brief introduction of several machine
learning paradigms and the components and functioning of each smart building
system we cover. Finally, we discuss challenges faced while implementing
machine learning algorithms in smart buildings and provide future avenues for
research at the intersection of smart buildings and machine learning