Ground source energy has been chosen for a new precision engineering factory in order to provide renewable heating and renewable cooling. Machining of components in exotic metals requires air temperatures to be controlled very precisely in order to meet the exacting tolerances required by aerospace clients. The new factory is cooled in summer by transferring surplus heat down to a borehole field in the ground. When heat is required in winter, heat is recycled back to the building from the borehole field to maintain a comfortable temperature in the building all year round. This is achieved by an automated system that balances the temperature in the building with the stable temperature natural to the ground by transferring heat from the ground in winter and storing surplus heat in the ground in summer: this achieves recycling of heat using precision engineering.