Disclosed are methods for providing heating and/or cooling of the type comprising evaporating refrigerant liquid and condensing refrigerant vapor in a plurality of repeating cycles, where the method comprises (a) providing the refrigerant comprising at least about 5% by weight of a lower alkyl iodofluorocarbon; and (b) exposing at least a portion of said refrigerant in at least a portion of said plurality of said cycles to a sequestration material comprising: i) copper or a copper alloy; ii) a molecular sieve (preferably a zeolite), comprising copper, silver, lead or a combination thereof; iii) an anion exchange resin, and iv) a combination of two or more of these, wherein said exposing temperature is preferably above about 20 C.