Effects of three landscape treatments on residential energy and water use in Tucson, Arizona

In this early study, three 1/4-scale models of houses were built and surrounded by xeriscape plantings, lawn, or shrubs shading building walls to determine the impacts on air-conditioning use. The cost-effectiveness of each was determined, accounting for both energy costs and water use for irrigation. Interior temperatures were not significantly different, but the xeriscape model used 20-30% more energy for air conditioning. Both turf and shade shrubs were still cost-effective once water costs for irrigation were taken into account, but the low to moderate water use shrubs were far more so. Interesting results related to differences in longwave radiation fluxes for turf vs xeriscape are presented with implications for computer modeling.