🔍 Key Concepts

• Relative humidity vs. air temperature in a closed space • How an A/C evaporator coil removes moisture from the air (condensation on the cold coil) • Effect of longer compressor run time when you lower the thermostat setting

💭 Think About

• When the thermostat is set lower, does the unit run more or less, and how does that affect moisture removal on the cooling coil? • If the air temperature drops but the actual amount of water vapor in the room changes only slightly, what happens to relative humidity? • Is the main job of the thermostat setting to change fan speed (air circulation) or to change how much cooling/dehumidifying the coil provides?

✅ Before You Answer

• Decide whether lowering the thermostat mainly affects temperature/humidity or fan speed/air circulation • Recall that as air passes over a very cold coil, water condenses out of the air—what does that do to relative humidity in the room? • Before picking an answer, ask: with a lower thermostat setting, would the room feel more cool and dry or cool and clammy?