I haven't artificially cooled since our first year but our basement naturally cools down in the winter. Temps got down to 70 in the room & 75-ish on the cool side of most of the tubs w/ 86-89 on the warm side. Now that the weather is warming up its 75-ish in the room and 80 cool/89 warm in the tubs. Out of 13-14 parings we should be getting 11-12 clutches this year .