Generally it is whisper quite for me you can not hear it in an office environment or in my home office. At times it seems to snag on maybe a flash page and the fan kicks in. You can definitely hear it then. Its a once a week thing for me. I don't think much of it as I usually have 20 -30 tabs open in safari so price I pay. A restart usually remedies the issue.I currently have a Macbook Pro 15 inch and it can very very loud and hot. Is the MBA any better in this regard?