Fan issues MBA 2012

[Pavel08]

Hello. In summer I bought the new MBA (2.0 GHz with turbo up to 3.1 i7, 8 GB RAM, Intel HD Graphics 4000 512 MB).

At the beginning I could never hear the fans spinning. It was completely silent. Its still is, unless i start watching some videos online. Then its just a nightmare. The fans are going crazy and its really noisy. Its been like that for a couple of months already. Im so tired of it.

For example the week after i got my MBA i watched like 30 episodes of Big Bang Theory online and I never heard the fans. But now, if I go to the same website and start watching them again, the fans gets really noisy only after 20 minutes.

I checked activity monitor for 1080p video on youtube. Whenever I view a video in 1080p the Flash Player is always staying at around 107% of CPU. If i pause the video, the cpu is back to normal. Ive attached some screenshots.
What is the problem? How can I fix it? Im so tired of that noise. I would really appreciate if somebody would help me.