I was recently asked to look into the optimum temperature for comms rooms - not data centres - housing branch office routers, switches and a few servers. I was quite surprised that the limiting devices in terms of temperature range were the UPSs backing the routers and core switches. 20-25 C is the optimum, apparently. Too warm and the battery life is significantly reduced. Too cool and the battery power can drop, or the battery can even be damaged (in extreme situations).
Test regularly, and follow the manufacturer's recommendations for maintaining good battery health. Expect to change the battery every 3 - 4 years, or less if the temperature is significantly outside the optimum (and /or you don't follow best practice).