To add to what has already been stated: +95% of the time when recipes refer to recommended fermentation temp, it refers to beer temp, so adjust ambient lower accordingly. In my experience, most standard beers up to about 1.070 will create maximum exothermic temperature above ambient temperature of about 4 - 6 degrees fahrenheit, as others have stated. How high depends in part especially on your pitching and ferment temps and the specific yeast. Of course the height of the temp swing is at the peak of fermentation. Bigger beers, especially with some Belgian yeasts the temp swing is normally 6 - 8 degrees fahrenheit.