Device for preventing damage to crops using heated ambient air, comprising: - a frame (101;104) comprising a floor plate; - one or more gas reservoirs arranged in the frame (101;104) on top of the floor plate; wherein the bottom sides of the gas reservoirs face the floor plate; - a gas burner operatively connected to the gas reservoirs, and configured for heating, by means of the combustion of gas from the gas reservoirs, ambient air supplied via an inlet and discharging it at an outlet; and - a centrifugal fan operatively connected to the outlet of the gas burner for drawing in the heated ambient air via an inlet and blowing out the heated ambient air via one or more outlets of the centrifugal fan; the device further comprises: - a heating device for the gas reservoirs comprising one or more channels configured for: - branching off a part of the flow of the heated ambient air to an outlet of the centrifugal fan via an inlet; - allowing the branched-off heated ambient air to flow through one or more channels to one or more downstream outlets of the one or more channels; characterized in that the device further comprises: - respective openings provided through the floor plate at the locations where the gas reservoirs are placed on the floor plate with their bottom sides; said one or more channels of said heating device for the gas reservoirs being configured for allowing the branched-off heated ambient air to flow through the openings upwards to the bottom side of the at least one gas reservoir via the one or more outlets. - a frame (101;104) comprising a floor plate; - one or more gas reservoirs arranged in the frame (101;104) on top of the floor plate; wherein the bottom sides of the gas reservoirs face the floor plate; - a gas burner operatively connected to the gas reservoirs, and configured for heating, by means of the combustion of gas from the gas reservoirs, ambient air supplied via an inlet and discharging it at an outlet; and - a centrifugal fan operatively connected to the outlet of the gas burner for drawing in the heated ambient air via an inlet and blowing out the heated ambient air via one or more outlets of the centrifugal fan; the device further comprises: - a heating device for the gas reservoirs comprising one or more channels configured for: - branching off a part of the flow of the heated ambient air to an outlet of the centrifugal fan via an inlet; - allowing the branched-off heated ambient air to flow through one or more channels to one or more downstream outlets of the one or more channels; characterized in that - a heating device for the gas reservoirs comprising one or more channels configured for: - branching off a part of the flow of the heated ambient air to an outlet of the centrifugal fan via an inlet; - allowing the branched-off heated ambient air to flow through one or more channels to one or more downstream outlets of the one or more channels; characterized in that - branching off a part of the flow of the heated ambient air to an outlet of the centrifugal fan via an inlet; - allowing the branched-off heated ambient air to flow through one or more channels to one or more downstream outlets of the one or more channels; characterized in that the device further comprises: - respective openings provided through the floor plate at the locations where the gas reservoirs are placed on the floor plate with their bottom sides; - respective openings provided through the floor plate at the locations where the gas reservoirs are placed on the floor plate with their bottom sides; said one or more channels of said heating device for the gas reservoirs being configured for allowing the branched-off heated ambient air to flow through the openings upwards to the bottom side of the at least one gas reservoir via the one or more outlets.