Scent dispenser arrangement for dispersing fragrance into a HVAC system includes a flow sensor and a scent disperser assembly having a control module connected to the flow sensor and a canister for emitting a spray which is actuated by the control module. The flow sensor operates in response to air flow and creates an air flow dependent electrical signal transmitted to activate the control module of the spray disperser assembly. The scent disperser and flow sensor are arranged to allow the spray to be disbursed in selective locations in the HVAC system. An embodiment involves two scent disperser assemblies electrically connected in series which operate successively when the liquid in one disperser assembly is depleted or when one disperser assembly dispersers a predetermined number of sprays. A further embodiment involves pressurized containers which communicate with a scented liquid reservoir having a sprayer, wherein a pressure differential in the reservoir triggers the pressurized containers to deliver a liquid flow into the reservoir.