Today, choosing a refrigerant involves considering the possibilities of phaseout, legislative action, or damage to a company's public image. Also, more companies are focusing on sustainability and protecting the environment. For these reasons, designers are considering natural refrigerants, but are they able to compete with other refrigerants on efficiency and running costs? The answer is yes, according to a study discussed in this article that compares various system configurations. With the right configuration, systems built with natural refrigerants can provide higher efficiencies than state-of-the-art HFC systems.