Recommendations for 2009 IECC 15% Above Code Energy Efficiency Measures for Residential Buildings

Abstract

In the 79th Legislature (2005) the Energy Systems Laboratory was required to develop three alternative methods for achieving 15% above-code energy savings in new residential, commercial and industrial construction. The Laboratory continues to work closely with code officials, energy raters, manufacturers, state officials and other stakeholders to develop cost effective energy efficiency measures. This report presents detailed information about the recommendations for achieving 15% above-code energy performance, which are based on the 2009 International Energy Conservation Code (IECC), for single-family residences across the State of Texas. To estimate above-code savings (%) of energy efficiency measures, total source energy savings from heating, cooling, lighting, equipment, and DHW were considered for emissions reductions determination. The recommendations were developed for three 2009 IECC climate zones in Texas along with simple payback calculations. This information is useful to homebuilders, utility demand side energy managers, homeowners and others who wish to construct residential buildings that exceed the minimum national energy code requirements. The analysis was performed using an ESL simulation model based on the DOE-2.1e simulation of a 2009 IECC code-compliant, single family residence and the appropriate TMY2 weather files for seventeen counties in Texas for which TMY2 data is available. According to 2009 IECC Climate Zone, seventeen counties were categorized into three climate zones: Climate Zone 2, 3, and 4, and the 2009 IECC code-compliance base-case models were constructed for each climate zone. Two options based on the choice of heating fuel type were considered: (a) natural gas (gas-fired furnace for space heating, and gas water heater for domestic water heating), and (b) electricity (heat pump for space heating, and electric water heater for domestic water heating). A total of eighteen measures based on the energy savings above the base-case house were selected. These measures include building envelope and fenestration, HVAC system, domestic hot water (DHW) system, lighting and renewable options. The implementation costs of each individual measure were also calculated along with simple payback calculations. These measures were then combined to achieve the total source energy savings of the group is 15% above the base-case 2009 code-compliant house. As a result, three example combinations were proposed for each base case ((a) electric/gas house and (b) all-electric house) in each climate zone. Each combination was formed to have a different payback period. Finally, the corresponding emissions savings of each combination were calculated based on the eGrid for Texas.