Hyundai Repair: Hyundai accent gl 2001, hyundai accent, air conditioning compressor

Question
There is a whirring noise everytime I use the air conditioner or heat.  The heat and air work find but the noise is getting louder.  It is not a continuous noise but is very concerning.  Could it be just a belt? If so what belt would have to be tightened or replaced?

Answer
If it occurs even when the air conditioning compressor is not on, it won't be a problem with a belt.  Can you identify whether the noise is outside or inside the vehicle?  The common thread I see in your description is that the blower fan is running.  Most noise problems that occur only when the fan is running are caused by debris in the fan.  The solution to this would simply be to remove the blower fan, clear the debris, and reinstall the fan.