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The House

The Westbrook House is a 2713 square foot resource efficient house designed by Paul and Elena Westbrook. Completed in 1996 in Fairview, Texas (near Dallas), the house has been a model of energy and resource efficiency. The house design was awarded the 1996 NAHB Energy Value Housing Award for Innovative Design. See Awards/Media for more information.

Check the Utility Data for more detail. View a detailed pdf file of the design process and features. Our builder was Richard Harwood of Enviro Custom Homes, 972.418.7772.

Westbrook House

Westbrook House

Features of the House (click the links for more info)
- Passive Solar Design
- Structural Insulated Panel Walls (SIP)
- Double-Pane, Low-E, Argon-Filled, Vinyl Frame Windows
- Galvalume Standing Seam Metal Roof
- Ground Source (Geothermal) Heat Pump
- Active Solar Water Heating
- Desiccant Wheel Air to Air Heat Exchanger
- Partially Earth Bermed Garage
- Carpet made from Recycled Plastic
- Deck Boards from Recycled Plastic and Waste Cedar Shavings
- Compact Fluorescent Bulbs in All Fixtures
- Heat Recirculating Wood Stove with Outside Air Intake
- Low VOC Paint
- Aerobic Septic Treatment System
- 3.7 kW Solar Photovoltaic (PV) System (added 2012)
- 2.4kW wind turbine (from 2006-2014)
- 3600 Gallons of Rain Water Storage

Passive Solar Design - Passive Solar has a slightly different priority in the part of the country that we live in (near Dallas, TX). We are in a predominately hot and somewhat humid climate. We want to capture free heat from the sun in the winter, but our primary objective is eliminating unwanted sun in the summer. We know enough about the movement of the earth relative to the sun that it is very easy to pinpoint exactly where in the sky the sun will be for any given minute of any day at any location on the planet. This location will vary over the months due to the tilt in the earth's rotational axis. In the winter, the sun rises more in the Southeast and is low in the sky. In the summer it will rise in the Northeast and move high overhead. 

By placing the walls, windows, and overhangs in the right location you can virtually eliminate any direct sunlight in the house during the summer and still gain a considerable amount of free solar heat in the winter. That's basically a passive solar design. The house just passively sits there and takes advantage of this natural cycle of sun movement.

Keep shape square or rectangular - two story is more efficient than one
Orient the long axis east - west
Place most windows on the north and south - minimize east and west glazing
Install the right size overhangs on the south windows 


There are also other passive strategies such as the color and materials of the walls and roof. The insulation value and the thermal mass of the building must be considered also. Again, most of these items do not really cost any additional money. The require no maintenance, replacement, or additional care. A design that takes advantage of the solar cycle is really so simple and elegant that I can't believe that more people don't take advantage of it.


See the free: Passive Solar Design Guidelines



Summer Solstice

South Wall Shaded @ Solar Noon

The overhangs are sized to shade the south face in the summer. We get views and daylight, but not unwanted heat gain.

Equinox

South Wall Shade Transition @ Solar Noon

The shade line is right at the window bottom during the spring and fall equinox.

Winter Solstice

South Wall Sunlit @ Solar Noon

The low angle of the winter sun allows direct solar gain into the house in winter.

Structural Insulated Wall Panels (SIP)

Our walls and roof are made from insulated panels. These panels have a foam core (EPS or polyurethane) and a skin of oriented strand board sheathing. There are no studs in the walls, so the insulation is consistent. The door and window openings are cut at the factory and the panels assembled quickly onsite. They provide a well-insulated and air-tight shell. Our panels are made by Korwall and are 6" for the wall (R-23) and 8" for the roof (R-30). Insulation and infiltration are two of the most important items  to increase comfort and lower energy use. SIPs addres both issues.

Structural Insulated Panel (SIP)

Windows

Window placement, shading, and quality are very important factors in good home design. We selected quality windows with a vinyl frame (good insulation and low maintenance), a low U-value (to reduce conduction), a low-E coating (to reduce radiant heat gain), low inflitration, and high visible light transmission (VLT). We placed most of the windows on the south, with very few on the east  and  west. The windows have proper overhang sizing to reduce unwanted heat gain in the summer.

Windows

Roof 

In a climate like ours, where we are tyring to reject heat for the majority of the year, the roof is a critical component. It faces the hot summer sun directly, so a reflective  (or cool) roof  is a key energy saving strategy. We chose a galvalume standing seam metal roof. It has good reflectivity and a very long life. It is also hail resistant, which qualifies us for a large homeowners insurance discount.

Cool Roof