I noticed the same thing doing my first batch. Those hungry yeasties get warm. I picked up a big 24 gallon Rubbermaid plastic storage container. Filled it about 1/4 to1/3 full with water and let it sit for a day or two at room (or garage depending on the fermentation temp I want) temp. I put the carboy in the container of water. This heat sink allows me to hold fermentation temp within a couple degrees.
Primary: , Boddington's Clone, Mirror Pond w/Marris Otter
Bottled: Fullers ESB Clone
Kegged: Mirror Pond Clone
Drinking: BM's Kona Fire Rock, Dead Guy Clone, Alaskan Amber Alt Clone, Firestone DBA Clone, Magnum/Crystal IPA
Next up: Burton IPA