After being used for a prolonged length of time, dehumidifiers can pick up all sorts of smells. Dehumidifiers have numerous components that are constantly damp and can harbor mold and mildew. A new dehumidifier with a strange smell is a different story. Identifying and solving the smell requires keeping a few things in mind.
Cycle the Unit
A good way to cut down on the smell emanating from a new dehumidifier is to simply cycle the unit a few times, which entails allowing the unit to dehumidify one full cycle, draining the water and repeating and can help cut down on any oils or other materials leftover from the manufacturing process. If the unit is functioning properly, meaning it is dehumidifying the air, you know it is likely not a mechanical issue that is causing the smell.
Wipe Down the Coils
Wiping down the coolant coils inside the unit is a good way to get rid of any excess oils or lubricant used on the copper while it is being manufactured. Use a damp sponge and a mild detergent, and wipe the coils clean while the unit is unplugged. Get as much of the coils as you can, front and back, and let them dry before turning the unit back on.
Burning Wire Smell
If you are smelling an odor that seems to indicate there is wire, or plastic, burning inside the unit, unplug it immediately. Return the unit to the store where you purchased it, or contact the manufacturer to find an authorized service center. Dehumidifiers are essentially self-contained air conditioners and contain many intricate and complicated moving parts. If something is overheating to the point of being odorous, it is likely a sign that your unit is faulty.
Most dehumidifiers have a filter and some have one on the air intake as well as the water output. Ensure you have removed any plastic films or wrapping on the filters, and change the air filter if necessary. You likely either have a faulty filter or one that has a fragrance or chemical added.