If you really want a quiet (and almost silent miner) you could look at USB miners. However, do not expect to make any money this way. You will NEVER make your money back. This is a way to do it just for fun, and get some very small payments in BTC and introduce you to mining/mining pools.
If you are interested in making some revenue, then you would have to mine from home. A miner will generate a lot of noise and heat (even the supposedly more domestically friendly models). This will quickly turn your office into a sauna and put off everyone nearby with he noise.
Alternatively, you could build an altcoin miner out of computer video cards, which will be quieter and generate less heat, mine alternative coins and then exchange them for bitcoin. Best looking in the altcoin section for suggestions in this area
Lol, USB miners like u2 and all will not gives the profit to you. If looks for profit we cannot get the returns for the electricity we paid for it.
Altcoin miners should be perfect for home or the commercial location but not fit for office and all. You will caught by your manager.