MacBook Air fan
MacBook Air 2020 fan runs continuously after light usage. It's not in hot temperature, on a soft surface, vents are not blocked and I already checked CPU and reset SMC. What else could it be?
Question marked as
If you're using a hard case / "skin" or keyboard cover, don't. Never use those things.
If you dig down through the links in About fans and fan noise in your Apple product - Apple Support, you will eventually find this passage from Keep your Mac laptop within acceptable operating temperatures - Apple Support:
"If your Mac laptop gets warm even when it isn’t doing tasks that require intensive calculations, or if it has fans that run for a long time, use Activity Monitor to check CPU activity. Look for malfunctioning processes that can put a significant load on the CPU and check for unexpected fan use. If issues persist, close and open the lid on your laptop, or restart your computer. ..."
Only after exhausting those possibilities should you suspect something amiss with the SMC, a hardware fault... those sorts of possibilities. The cooling fins can become very obstructed with dust before the fan noise starts to become objectionable.
Run Apple Diagnostics, which will exercise the fan and test that Mac's thermal sensors: Use Apple Diagnostics to test your Mac - Apple Support
Post a screenshot of Activity Monitor if you wish. Use the Energy pane, or CPU sorted by %CPU to see which apps or processes are using the most energy or placing the greatest demands on your Mac's CPU, respectively. To show the most relevant information I suggest selecting "Active Processes" from Activity Monitor's View menu.