What indoor temperature must active or passive space-heating systems maintain?

Active or passive space-heating systems must maintain a minimum indoor temperature of 68°F to ensure the health and comfort of the building occupants. This threshold is established in the International Mechanical Code to provide a standardized level of warmth during colder weather conditions. Maintaining this temperature helps to prevent issues such as discomfort, potential health risks associated with cold environments, and damage to infrastructure that can occur due to inadequate heating.

Other options, while they may seem reasonable, do not align with the established code requirements for minimum indoor heating, which has been specified as 68°F to provide effective heating and comfort for occupants in various indoor settings.