A rooftop exhaust fan for exhausting air from a building comprising: a fan assembly including a housing, a motor disposed in the housing, and a fan driven by the motor and configured to induce air to move from the building through the fan assembly; one or more dampers moveably mounted to the fan assembly above the motor and the fan and configured to move from a generally horizontal closed position to a raised open position where in the open position exhaust air moves upwardly through the fan assembly and past the damper; a damper actuator assembly configured to open the damper in response to an electricity failure or a motor failure, the damper actuator assembly comprising: i. at least one pivot arm disposed underneath the damper and configured to move from a generally horizontal position to a raised position where the pivot arm engages the damper and moves the damper to the raised open position; ii. a mechanical fusible link connected to the pivot arm and configured to normally hold the pivot arm in the generally horizontal position; iii. a gas spring piston attached to the fan assembly and extending therefrom where the gas spring piston is connected to the pivot arm, the gas spring piston being biased to move from a retracted position to an extended position; iv. wherein the mechanic fusible link is heat sensitive and configured to break in response to being exposed to a threshold temperature; and v. in response to the mechanical fusible link failing, the gas spring piston is configured to move from the retracted position to the extended position and to engage the damper and raise the damper to the open position such that exhaust air can be exhausted upwardly past the damper; whereby in response to an electricity failure or the motor failing and the mechanical fusible link breaking, the pivot arm raises and engages the damper and moves the damper to the raised open position. a fan assembly including a housing, a motor disposed in the housing, and a fan driven by the motor and configured to induce air to move from the building through the fan assembly; one or more dampers moveably mounted to the fan assembly above the motor and the fan and configured to move from a generally horizontal closed position to a raised open position where in the open position exhaust air moves upwardly through the fan assembly and past the damper; a damper actuator assembly configured to open the damper in response to an electricity failure or a motor failure, the damper actuator assembly comprising: i. at least one pivot arm disposed underneath the damper and configured to move from a generally horizontal position to a raised position where the pivot arm engages the damper and moves the damper to the raised open position; ii. a mechanical fusible link connected to the pivot arm and configured to normally hold the pivot arm in the generally horizontal position; iii. a gas spring piston attached to the fan assembly and extending therefrom where the gas spring piston is connected to the pivot arm, the gas spring piston being biased to move from a retracted position to an extended position; iv. wherein the mechanic fusible link is heat sensitive and configured to break in response to being exposed to a threshold temperature; and v. in response to the mechanical fusible link failing, the gas spring piston is configured to move from the retracted position to the extended position and to engage the damper and raise the damper to the open position such that exhaust air can be exhausted upwardly past the damper; i. at least one pivot arm disposed underneath the damper and configured to move from a generally horizontal position to a raised position where the pivot arm engages the damper and moves the damper to the raised open position; ii. a mechanical fusible link connected to the pivot arm and configured to normally hold the pivot arm in the generally horizontal position; iii. a gas spring piston attached to the fan assembly and extending therefrom where the gas spring piston is connected to the pivot arm, the gas spring piston being biased to move from a retracted position to an extended position; iv. wherein the mechanic fusible link is heat sensitive and configured to break in response to being exposed to a threshold temperature; and v. in response to the mechanical fusible link failing, the gas spring piston is configured to move from the retracted position to the extended position and to engage the damper and raise the damper to the open position such that exhaust air can be exhausted upwardly past the damper; whereby in response to an electricity failure or the motor failing and the mechanical fusible link breaking, the pivot arm raises and engages the damper and moves the damper to the raised open position.