How do lighting rules of thumb impact HVAC system sizing?

Lighting rules of thumb directly impact HVAC system sizing, as the estimated lighting load is used to determine the required cooling capacity of the system. If the lighting load is underestimated, the HVAC system may be undersized, leading to inadequate cooling and discomfort for occupants. Conversely, if the lighting load is overestimated, the HVAC system may be oversized, leading to wasted energy and increased costs.