What does the term "conditioned space" mean in HERS ratings?

The term "conditioned space" refers specifically to areas of a home that are heated or cooled to maintain comfort levels for the occupants. This is a critical concept in the context of energy efficiency and the Home Energy Rating System (HERS), as it directly relates to how much energy a home uses for space heating and cooling.

Conditioned spaces are actively managed through HVAC systems to ensure that the temperature and humidity levels are within a range that is comfortable for occupants. Understanding this definition is vital for evaluating the thermal performance of a home and for implementing improvements that can lead to lower energy consumption and increased comfort.

In contrast, unconditioned spaces, which are not heated or cooled, do not provide the same comfort levels and generally involve separate construction considerations, as they can impact how heat moves through a home. Renovated spaces may become conditioned or unconditioned depending on the upgrades performed, but that is not a defining characteristic of conditioned space. Lastly, while energy-efficient windows may be installed in conditioned spaces, they do not define what conditioned space is; rather, they are part of an energy efficiency strategy to enhance the performance of those spaces. Therefore, the correct understanding of conditioned spaces is fundamental in HERS ratings and energy assessments.