Which of the following is not included in the unitary small equipment category?

The unitary small equipment category typically refers to self-contained systems that are capable of cooling or heating spaces and are generally designed for residential or small commercial applications. Packaged terminal air conditioning units (PTACs) are designed for use in locales such as hotels or apartments where they can be installed through a wall, providing individual climate control. They are part of the unitary equipment category but are distinguished from more compact and mobile options.

Central air conditioning systems, window air conditioning units, and portable air conditioning systems all fall under various subcategories of unitary equipment. However, the difference lies in how they are designed to operate and the intended application. While window and portable units are small and typically serve single rooms, central systems serve multiple spaces from a single unit.

The correct answer highlights that packaged terminal air conditioning units, due to their built-in nature and specific application design, are a distinct category, separate from more portable or traditional unitary systems like window units or portable options. This understanding is crucial in distinguishing various HVAC systems based on their design and operational parameters.