Programmable thermostats are generally not recommended for heat pumps. When the heat pump is cooling the house, manual or programmable thermostat will save energy and money. But when the same heat ppump will heat up the house by reversing the cycle, setting back its thermostat can make the unit to operate inefficiently. It will nullify the savings achieved in cooling mode. In case of heat pumps maintaining a moderate temperature is recommended. However today certain companies are offering specially designed programmable thermostats for heat pumps, which make setting back the thermostat cost-effective. They minimize the use of backup electric resistance heat systems by using special algorithms.