What is the minimum indoor temperature that space heating systems must maintain in interior spaces intended for human occupancy?

The minimum indoor temperature that space heating systems must maintain in interior spaces intended for human occupancy is generally 68 degrees Fahrenheit. This standard is established to ensure comfort and health in residential and light commercial settings.

At this temperature, occupants can maintain a comfortable environment, reducing the risks of cold-related health issues such as hypothermia or respiratory problems which can arise in inadequately heated spaces. Additionally, many building codes and regulations, such as those from the International Code Council (ICC) or local building authorities, specify 68 degrees as a baseline to ensure safety and comfort across various types of buildings.

Maintaining this minimum temperature is particularly important in areas where extreme weather conditions are common, as it helps protect both the structure of the building and the well-being of its occupants.