Defoaming compounds that can be included in a HVAC system are provided. In some embodiments, the refrigerant compositions and/or additives may include one or more defoaming compounds that have one or more of the following properties: helping reduce a surface tension of the lubricant and/or refrigerant; having a different surface tension than the lubricant and/or refrigerant; being substantially non-dissolvable with the refrigerant and/or lubricant; and/or having less dense than the refrigerant and/or lubricant so that the compounds may stay on the surface of the refrigerant and/or lubricant. In some embodiments, the defoaming compounds may be selected from mineral oil, silicone based oil, fatty alcohols, fatty acids, alky amines, treated silica, aluminum oxide, polyacrylates, acrylate esters polypropylene, alkyl sulfates, alkyl ethoxylate sulfates, alkyl aryl sulfonates, phosphate esters, quaternary ammonium compounds, fatty amine salts, fatty acid amides, alkyl phenol ethoxylates, ethoxylate-propoxylate polymers and fatty alcohol ethoxylates.