Keeping up with the energy requirements of current day supercomputers is fast becoming a major challenge. The major consumers of energy in an HPC datacenter are machine, interconnect and cooling. As of today, most of the research has focused on saving machine energy consumption leaving behind energy spent on cooling which takes about 40% of the total energy consumption for a datacenter. Our focus is to extend energy optimization work beyond machine energy saving so that we save cooling energy as well as energy used by the interconnect. Most datacenters do excessive cooling in order to avoid hotspots (areas in the machine room which are at a much higher temperature than other parts of the room). We are working on a runtime system which uses Dynamic Voltage and Frequency Scaling (DVFS) in order to minimize the occurrence of hotspots by keeping core temperatures in check. While doing so, our scheme reduces the timing penalty associated with using just DVFS by doing chare migration in order to load balance the application. Our results show that we can save considerable cooling energy using this temperature aware load balancing.