August 30, 2018

Building Energy-Efficient and Affordable Homes in Hot and Humid San Antonio

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Home builders like River Star Homes and building material manufacturers like Bautex Systems are tackling the challenge of building energy-efficient and affordable homes in hot and humid San Antonio, Texas.

Building energy-efficient homes in San Antonio begins with the design of a tight and well insulated building envelope. When builders utilize the Bautex Wall System they create highly insulated, moisture-resistant, and airtight homes that are critical in the hot and humid climate of San Antonio.

Affordable Housing Shortage in San Antonio

Building energy-efficient, low maintenance and affordable homes in San Antonio is needed to accommodate San Antonio’s growing population and shrinking inventory of reasonably priced and quality homes. The challenge to builders and architects in San Antonio is to construct homes a new buyer can both afford to buy and live in.

Specifically, in San Antonio, energy-efficient design is essential for ensuring low long-term energy and maintenance expenses. New homes must be affordable and energy-efficient to meet the housing demands of San Antonio.

Building Energy-Efficient and Affordable Homes in Hot and Humid San Antonio

Designing an energy-efficient home in San Antonio must consider the climate and geography of the region. San Antonio lies in south-central Texas, about 140 miles from the Gulf of Mexico. Most of the time, easterly, southeasterly winds off the Gulf of Mexico dominate San Antonio.

The steady flow of wind brings moisture to the area, resulting in a humid subtropical climate. Much of the year, the relative humidity in San Antonio is above 80 percent in the early morning. Humidity drops to near 50 percent in late afternoon.

The average monthly temperatures in San Antonio range from the 50s in winter to 80s in summer. However, summers are often long and hot with daily maximum temperatures above 90 degrees over 80 percent of the time. Addressing the extreme heat and humidity in San Antonio is critical to building an energy-efficient and affordable home.

Critical Elements of Energy-Efficient and Affordable House in San Antonio

Builders and architects of affordable homes in San Antonio must consider energy-efficiency for all construction. However, when constructing affordable housing in  San Antonio, energy-efficiency is essential to ensuring that a homeowner can handle the day-to-day expenses and long-term maintenance costs inherent in home ownership.

Critical elements of an energy-efficient home in San Antonio include proper building orientation, continuous insulation in the walls and roof, airtight building envelope, quality and properly installed windows and doors, and a well designed HVAC system.

Energy-Efficient Homes in San Antonio Need Robust Building Envelopes

Critical design elements for a robust building envelope include continuous insulation  and  air and moisture barrier. A continuous air and moisture barrier minimizes air infiltration and moisture intrusion, which is essential to creating an energy efficient and durable home in San Antonio. Moisture resistance is critical to stopping rot and the growth of mold and mildew, which can diminish the indoor environmental quality (IEQ) of a home.

Continuous insulation eliminates thermal bridging through the building envelope and maintains the energy performance of the insulating material. Up to 25% of conventionally framed walls has no insulation. Therefore, the insulation in the stud cavities only provides a fraction of the rated R-value that is advertised by the manufacturer. Continuous insulation systems provide the full rated performance.

The envelope must consider all the exterior elements of the house: the walls, roofing, foundations, doors, and windows.

High Performance Walls of Energy-Efficient Homes

The walls are a critical component to stopping heat gains and producing a robust envelope of an energy-efficient house. Several natural occurrences affect the efficiency of the walls: conduction, convection, and thermal radiation. The walls of an energy-efficient building should have low-thermal-conductivity and a high effective R-value4. The design of an energy efficient wall also incorporates materials with high thermal mass which amplifies the performance of the walls.  . Energy-efficient walls are a critical element of an efficien tbuilding envelope.

Building an Energy Efficient Home in San Antonio with the Bautex Wall System

The Bautex Wall System is a superior, high thermal mass product for producing a durable building envelope for an energy-efficient and affordable home in San Antonio. The Buatex Block meets the thermal performance mandated by the IRC and provides a high-level of continuous insulation.

The Bautex insulated concrete blocks provide an R-14 continuous insulation that meets, the latest building and energy codes (2015 IECC). Also, applying the Bautex AMB 20 air and moisture barrier to the Bautex Blocks produces a moisture-resistant, airtight house, critical in humid San Antonio.

The Bautex Wall System is the ideal choice for energy-efficient wall construction for affordable homes in San Antonio.

The Roof of an Energy-Efficient Home

  • A cool roof is crucial to the design of a home in San Antonio. Cool roofs protect against solar heat gain and keep the attic and house cool. Thermal mass materials for a cool roof like clay, tiles, or slate that are reflective or have light colored pigments that reflect the sunlight are excellent options for cool roofs.  

Insulating The Foundation on an Energy-Efficient Home

Installing a continuous layer of rigid foam insulation on the exposed slab edges of concrete foundations will increase the energy efficiency of a home. A significant amount of heat flow can occur from the inside of a home through the foundation where it is exposed to the outside. Including this insulation detail is extremely beneficial, but is rarely done correctly.  

The Glazing System of an Energy-Efficient Home

Home Orientation of an Energy-Efficient Home in San Antonio

Site orientation of a house is critical for taking advantage of the sun’s energy.  For instance, in the Northern Hemisphere homes should be oriented north-south. The north-south orientation limits direct sunlight during the summer (which lessens cooling demands) while maximizing sunlight during the winter (which reduces heating requirement).

Room Location of an Energy-Efficient Home in San Antonio

Room configuration is also an essential design consideration of an energy-efficient home in San Antonio.

  • North facing rooms have good sun most of the day and are perfect for the main living spaces like living, family, land dining rooms.
  • East facing rooms have good sun in the morning and are cool in the late afternoon, which is ideal for bedrooms, kitchens, and breakfast nooks.
  • South-facing spaces have low levels of sunlight and are nice areas for garages, laundries, and bathrooms.
  • West facing rooms get the late day sun, which is not good for kitchens and bedrooms.

Windows of an Energy-Efficient Home in San Antonio

Windows of an energy-efficient home in San Antonio should face north or south. Avoid east- and west-facing windows because they contribute more to overheating than north- or south-facing windows.

Ductwork Location of an  Energy-Efficient Home in San Antonio

For an energy-efficient new house in San Antonio, locate the ductwork inside the home’s envelope. Ducts placed in unconditioned spaces can increase cooling expenses by 15 percent. Furthermore, in hot and humid regions moisture will collect on the overheated ductwork.

San Antonio Needs Energy-Efficient and Affordable Housing

Builders in San Antonio, Texas, like River Star Homes, are challenged with constructing affordable and energy-efficient homes for the area's growing population. Building homes in hot and humid San Antonio require detailed attention to energy-efficient design.  

Energy-efficient design will ensure homeowners have affordable energy costs and durable homes. Please visit Bautex™ Wall Systems for more information on building energy-efficient and affordable homes in San Antonio, Texas.

1Thermal conduction is when warm molecules spontaneously move towards and collide with cooler molecules. The effective R-value of a home's wall assembly is its resistance to conduction (the movement of hot molecules towards cooler molecules).

2Thermal convection is the transfer of heat from a warmer space to a colder space by the flow of liquid or air molecules. A tightly sealed building envelope stops this flow, often with an air and moisture barrier.

3Thermal radiation transfers heat from a warm area to a cooler area by electromagnetic waves, which for homes is mainly the sun’s rays.

4A building's wall assembly resistance to this flow is measured by its effective R-value. The effective R-value includes all the materials used in its construction: the studs, siding, drywall, fiberglass batts, plywood or OSB sheathing, water control plane. The higher the R-value, the less the conductivities of the wall assembly.

5Thermal mass is the potential of a material to absorb and store heat energy. High thermal mass materials help stabilize temperature shifts within a home by slowing the rate of heat transfer.


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