An increase or decrease in the percent of all households that knowingly purchased an ENERGY STAR product could be due to changes in any of the three proportions listed above between 2008 and 2009. There were no statistically significant changes (at the 10-percent level) for the first two proportions, aided recognition or purchased product. However, the proportion of households who knowingly purchased an ENERGY STAR product decreased from 73 percent in 2008 to 62 percent in 2009 (p=0.010). The 2009 result is similar to the result reported in 2007, 68 percent (p=0.267).
Purchases of ENERGY STAR by Publicity Category
The proportion of all households that knowingly purchased an ENERGY STAR product in high- versus low-publicity areas is 32 and 34 percent, respectively. This two percentage point difference is not significant at the 10-percent level (p-value = 0.766). The market penetration of ENERGY STAR products decreased in high publicity categories from 44 percent in 2008 to 32 percent in 2009. This difference is significant at the 5-percent level of confidence (p-value = 0.023).
National Household Market Penetration of ENERGY STAR Products by Publicity Category [Base = All respondents]
High ** Low
p-value 0.023 0.574
(High minus Low)
2009 and 2008 proportions are statistically different from each other at the 5-percent level of significance (p-value≤0.05).