Design Around the Sun: A More Comfortable Central Texas Home Starts With the Site Plan

← Better-Built Homes series • Article 2 of 9

A beautiful floor plan can feel very different when it is placed on your actual lot. The same living-room windows may face gentle morning light on one property and intense afternoon sun on another. Custom construction gives you an opportunity to address that difference before it becomes a daily problem.

Start with true directions and seasonal sun paths

Mark true north on the survey and examine the sun’s path at different times of year. Sunrise and sunset positions shift seasonally; “the sun rises in the east” is not a complete design analysis. Trees, neighboring homes, slopes, and future development can change the light reaching a wall or porch. A lot visit at one hour on one day cannot show the whole picture.

Daylighting design coordinates window placement, glass, shading, and room use. DOE notes that controlling heat and glare is more difficult with east- and west-facing glass.^[1] That makes exposure an early planning issue, rather than a problem to hand entirely to the air conditioner.

This table is a planning framework, not a rule that a Texas home must face one direction. Room priorities, privacy, access, setbacks, and site constraints all matter.

Do not copy a cold-climate solar plan into a Texas home

Passive solar heating intentionally admits and stores winter sunlight, then controls summer gain. DOE’s guidance describes coordinating glazing, thermal mass, and shading.^[2] Central Texas design also needs a careful cooling-season assessment. Large areas of south-facing glass are not automatically an efficiency upgrade.

Evaluate the complete house: window-to-wall area, SHGC, insulation, air sealing, occupancy, and mechanical loads. A design can welcome winter daylight while avoiding unnecessary summer exposure. If a proposal relies on substantial solar gain or thermal mass, ask for an energy model rather than a general promise.

Shade the glass—and design outdoor rooms people will use

A roof overhang may suit higher sun angles but leave low-angle afternoon sun reaching the glass. Exterior screens, vertical shading, porches, and landscaping are options to study. DOE’s building-envelope guidance specifically identifies east/west glass as difficult to shade.^[3] Interior blinds can improve comfort and glare, but they should not replace consideration of the exterior design.

Ask when you expect to use the patio. A family that entertains after work needs a different sunlight study from someone who wants a sunny breakfast terrace. Model the roof edge, adjacent wings, and trees at those hours. Preserve useful daylight indoors while creating a shaded outdoor area; making a porch deeper can also make an adjoining room darker.

Where to spend the planning budget

Early studies are useful when they inform decisions you can still change. Request a site plan, seasonal shadow views, a window schedule, and a room-by-room comfort discussion before finalizing elevations. For difficult exposures, an energy model can help compare alternatives and their estimated operating effects. Avoid treating a modeled result as a guaranteed utility bill.

For an existing home or addition, start with the rooms that overheat or feel dark. You may have options involving shading, window specifications, or room arrangement even when rotating the house is impossible. Check how an addition will shade existing windows and where roof runoff will go.

Bring these details to the first conversation

• Your survey, property address, and preferred views.
• The rooms where morning or afternoon comfort matters most.
• When you use patios, porches, and outdoor kitchens.
• Trees to preserve and neighboring structures to consider.
• Budget priorities and any fixed design requirements.

Homeowner planning guidance for Austin, Cedar Park, Leander, Georgetown, Liberty Hill, Lago Vista, Jonestown, and Dripping Springs. Code requirements, climate conditions, existing construction, and product approvals vary. The comparisons and clearly labeled examples are not ADDRAC bids, performance guarantees, or a claim of certification.