Abstract: A device for heating fluids by employing a rotor-housing mechanism. The device comprises a rotor assembly comprising a cylindrical rotor attached to a shaft with an annular space defined therebetween, a multiplicity of oblique bores disposed on the surface the rotor, a closely conforming cylindrical housing enclosing the rotor air tightly. The housing is defined by a cylindrical wall with first and second end-sealing plates sealing the opposite ends of the wall. The device further comprises an inlet and an outlet for the ingress and egress of a fluid from in and out of the housing respectively. A motive means, such as an electric motor, is connected to the shaft. A fluid received within the housing is primarily subjected to fluid hammer effect and for increasing the temperature thereof substantially.