Abstract

In 2011 the residential sector in the United States, both directly (e.g. on-site gas appliances) and indirectly (e.g. power plant emission), emitted 1,162 million metric tons of carbon dioxide. Residential electricity consumption, of which 14% came from water heaters, accounted for 70% of total carbon dioxide emissions associated with the residential sector. Heat Pump Water Heaters (HPWH) are two to three times more efficient than Electric Resistance Water Heaters (ERWH) that are common in homes. Currently, North Carolina only requires electric water heaters with tanks larger than 55 gallons to be the more efficient HPWH for new homes. This study addresses the question, what costs and savings can be expected by requiring HPWH in all new residential construction? To estimate costs and savings differences in short term economic costs, long term economic savings, and carbon emissions reductions were examined. Data from the U.S. Census Bureau, the U.S. Energy Information Administration, and the U.S. Department of Energy were analyzed to estimate changes in upfront costs and reduced energy demand, which lead to lower electricity bills and carbon emissions over time. Results suggest that requiring HPWHs would lead to a 10-year savings of $125 million for North Carolina residents, as well as 10-year reductions in carbon dioxide emission of around 435,900 metric tons.

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