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Guides and Case Studies for Hot-Dry and Mixed-Dry Climates

Map of the Hot-Dry and Mixed-Dry Zone of the United States. The zone contains the eastern side of California and follows the US border to cover the western half of Texas.The Department of Energy (DOE) has developed a series of best practices and case studies to help builders improve whole-house energy performance in buildings found in hot-dry and mixed-dry climates.

Best Practice Guides

New Construction Case Studies


Project: Gordon Estates — Phoenix
Builder: Mandalay Homes
Profile: Fourteen homes in this subdivision achieved Challenge Home certification with HERS 38–58.


Project: Exterior Rigid Foam Insulation at the Edge of a Slab Foundation — Fresno
Builder: Wathen-Castanos Hybrid Homes, Inc.
Profile: The addition of exterior rigid foam insulation at the edge of the slab foundation for a single-family ranch house is estimated to achieve energy savings of 35.5%.

Project: Haciendas at Rancho Santalina, ZeroHouse 2.0 — San Marcos
Builder: KB Home
Profile: Designed to produce as much energy as it uses, the ZeroHouse incorporates a PV system, R-15 fiberglass batts in walls, and slab-on-grade foundation.

New Mexico

Project: Morrison Home — Albuquerque
Builder: Palo Duro Homes, Inc.
Profile: This house uses 2 × 6 wood framing, studs spaced 24 inches apart, and blown-in formadehyde-free insulation.

Improvements to Existing Homes Case Studies


Project: Passive Room-to-Room Air Transfer — Fresno
Builder: GreenEarthEquities
Profile: This project describes a strategy for providing conditioned air to bedrooms when the bedroom doors are closed and measured potential thermal discomfort that occupants may experience when this strategy is used.

Project: Inverted Attic Bulkhead for HVAC Ductwork — Roseville
Builder: K. Hovnanian Homes
Profile: This occupied test home received a modified truss system to accommodate ductwork within an inverted insulated bulkhead along the attic floor, which saves energy by placing heating, ventilating, and air-conditioning (HVAC) ductwork within the home's thermal boundary.

Project: Performance of Hot-Dry Climate Whole-House Retrofit— Stockton
Builder: Green Home Solutions
Profile: As a part of Stockton's Large-Scale Retrofit Program, this home underwent a deep retrofit project that expanded on the standard package by adding HVAC, water heater and window upgrades to the ducting, attic and floor insulation, domestic hot water insulation, envelope sealing, lighting and ventilation upgrades. Post-retrofit site energy savings were 23% compared to the pre-retrofit case.

You may also find case studies and guides that work across all climates on the All Climates page.

For additional, updated information on hundreds of building science topics that can help you build or retrofit to the most recent high-performance construction criteria, including the latest version of ENERGY STAR and the DOE Challenge Home requirements, see the Building America Solution Center.