A low-energy building also, known as a "passive house," is a structure made to use little energy as possible to heat and cool. We construct it with high levels of insulation and airtightness, which helps reduce heat loss in the winter and heat gain in the summer. We also use natural light and airflow instead of artificial lighting and air conditioning to make homes comfortable. In contrast, an energy-saving home is a structure that is designed and constructed to lower its overall energy usage. We accomplish this in many ways, utilizing energy-efficient appliances and lighting, installing solar panels, and employing intelligent home technologies to monitor and control energy consumption.