Estimates of non-market values are valuable for policy makers. However, evidence of the stability of value estimates over long timeframes is limited. That can reduce the usefulness of such values in benefit transfer over time. Furthermore, the values might be affected by the choice of presentation of alternatives (e.g., labeled versus unlabeled). Most of the literature comparing the willingness-to-pay (WTP) estimates lacks an investigation of temporal stability for labeled and unlabeled alternatives. In this case study, the temporal stability of WTP estimates for emissions reduction has been assessed for labeled and unlabeled alternatives. Emissions reduction, certainty of emissions reduction and the options for emissions reductions such as green power, efficient technologies and carbon capture were used to identify respondents’ WTP. The results show that WTP has changed significantly over the course of 10 years. The case study identified that WTP was larger for labeled alternatives than for unlabeled alternatives. The results indicate that WTP estimated from unlabeled alternatives may be more sensitive to temporal effects than labeled alternatives.