Found this article on the net, hope it helps
The average amount of calories burned for 30 minutes session of sex is 150. When you would compare it to other activities that you actually do on a daily basis, you would see that you burn more with sex than the rest. Housework can burn only 111 cals, Yoga 114 cals, and dancing 129 cals. Sex is actually said to be a legitimate form of exercise that lowers cholesterol level.