Some window installations, informally

ACS

["Hint: \"They might be cranked up in the summer to keep things cool.\"\n\nThis hint suggests the context of cooling systems (air conditioners) without directly mentioning the abbreviation or the word \"air.\" It nudges the solver toward thinking about temperature control and common informal terms for such devices."]

The clue **"Some window installations, informally"** leads to the answer **"ACS"** through the following reasoning: 1. **"Window installations"** refers to **air conditioning units**, which are often installed in windows. 2. **"Informally"** suggests an abbreviation or shorthand term. 3. **"ACS"** is a common informal abbreviation for **"air conditioners"** (or "air conditioning systems"). Thus, the clue cleverly combines the idea of window-mounted air conditioners with the informal abbreviation to arrive at the answer.