Understanding Conditioned V. Unconditioned Spaces

Any area inside a building envelope where temperature and humidity are controlled is called a conditioned space. This includes the active and living spaces found in both residential and commercial buildings. Alternatively, an unconditioned space is any space inside a building envelope with no means of regulating temperature or humidity – areas like garages, attics, or crawl spaces. In this case, the interior space conditions approach those of the outdoors.

Taking these spaces into account goes beyond basic levels of comfort. Ductwork, plumbing, and similar elements need to be installed inside the controlled spaces of the structure or be constructed and properly shielded to survive outside of it. This planning is vital not only in the construction of a structure, but in the occupancy of it as well. For example, if a basement is a conditioned space, an insulated cold-water pipe won’t absorb heat. If a space is in a climate area with 100% humidity, cold pipes can be prone to condensation issues. Likewise, cold water pipes in an unconditioned area of a structure can freeze in winter.

Maintaining a controlled space properly, even when vacant, is important. If left unmonitored, the space can become an uncontrolled space with less than desirable outcomes. The loss of conditioned air increases heating and cooling demand. Humid indoor air that escapes into the attic can condense on cold roof sheathing, resulting in potential moisture problems. Warm air that escapes into the attic in winter can warm the roof deck and increase the risk of ice dams. Not only could the temperature sensitive pipes be subjected to critically low temperatures, resulting in freezing and bursting, but on the opposite end of the temperature spectrum, sprinkler heads in fire suppression systems could be triggered by prolonged exposure to excessive hot temperatures.

CED Technologies employs engineers with expertise in dealing with conditioned and unconditioned spaces, and any issues that may arise from them. Contact us to review your next case or submit a case request online.