What is the minimum indoor temperature that a space heating system must maintain in an occupied interior space measured at 3 feet above the floor?

The minimum indoor temperature that a space heating system must maintain in an occupied interior space is clearly defined by building codes and standards. Maintaining a temperature of at least 68°F at a height of 3 feet above the floor ensures comfort for occupants and prevents potential health risks associated with cold environments. This standard is based on the physiological needs of people, which help sustain their well-being and productivity.

Thermal comfort is critical in occupied spaces, and setting the minimum at 68°F helps reduce the risk of discomfort and other cold-related issues. Having such a benchmark also supports energy efficiency measures, allowing buildings to function effectively while ensuring that systems are not overburdened.

The other temperatures do not meet the commonly accepted minimum for comfort and safety in inhabited spaces, which further solidifies 68°F as the correct choice.