Trends in Passive Design in Texas Homes

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As the res­i­den­tial new build market continues to move towards green and energy efficient options, Net Zero con­struc­tion is picking up speed. Net Zero houses — those that generate as much energy as they consume — are becoming increas­ing­ly common. There are even entire Net Zero sub­di­vi­sions being built in Texas cities these days.

When building a Net Zero house, it’s important to ensure it is designed to be as energy efficient as possible from the very beginning before adding renewable energy systems. By reducing a home’s energy require­ments, Net Zero is easier to achieve.

That’s where passive design can come into play.

Using smart building materials to manage heat fluc­tu­a­tions through­out the day, passive design harnesses natural elements to drive energy effi­cien­cy and reduce costs.

In Texas, archi­tects are often looking for passive design solutions that help cool homes in the summer and keep them warm in the winter. To achieve this, passive design must focus on building ori­en­ta­tion, size, and con­fig­u­ra­tion of windows, and materials and systems that can both heat and cool homes based on seasonal and daily variations.

Managing Direct Energy Gains

Given the large tem­per­a­ture swings through­out the day and the mix of heating and cooling days, Texas is ideally suited to passive house design. In passive design, buildings in the northern hemi­sphere are designed with south-facing windows to bring in as much sunlight and heat as possible into the home in the winter. 

In the summer, shading systems over these windows block direct sunlight from entering the home, keeping the inside cooler. With more than 300 sunny days in El Paso each year, there’s a lot of energy to be gained and the home could be over­heat­ed without pre­cau­tions. Passive houses often incor­po­rate triple-glazed windows, as well as overhangs and shading, to avoid overheating.

For instance, this passive house uses tra­di­tion­al-looking overhangs above windows in direct sunlight, while still incor­po­rat­ing the archi­tec­tur­al feel of the home.

Land­scap­ing can also be used to help manage direct energy gains. In colder climates, shade from trees can be a lim­i­ta­tion to solar heating, but on hot Texas summer days, strate­gi­cal­ly planted trees can help manage solar overheating.

Thermal Mass

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One of the key com­po­nents of passive design is thermal mass. That’s when you use building materials that help to regulate con­sis­tent internal tem­per­a­ture even while external con­di­tions change with weather or time of day. Selecting building materials designed with thermal mass in mind is critical to the success of passive design.

Archi­tects and home builders fre­quent­ly choose natural or tra­di­tion­al building materials like stone, concrete, and brick because of their thermal mass prop­er­ties. These materials absorb and hold heat better than wood or steel.

If you’re looking for an engi­neered solution, ICF wall systems such as Bautex Blocks and Bautex Wall System use insulated concrete, which is ideally suited to keep Texas homes cooler during summer heat and to preserve warmth on colder winter days. Plus, Bautex products have the added advantage of being more cost effective than many other tra­di­tion­al options.

Night Purging

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If you’re warm, open a window.” We’ve all been told this at least once in our lives. There is nothing new about night purging as a way to passively cool a space. Night purging is as simple as leaving your windows open at night to help cool off living areas after a warm day.

Passive design uses the basic principle of night purging and then takes it further, bringing in cool night air through ven­ti­la­tors or specif­i­cal­ly designed mechan­i­cal units. And where these units generate heat through motors, this heat can be recovered and recycled into domestic hot water systems, further lowering energy demands and costs.

Airtightness

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Air­tight­ness is critical to the success of passive design. Why go to all the trouble of building a home that balances its own air tem­per­a­ture if that air is just going to escape out of poorly sealed walls and windows? But improved air­tight­ness also runs the risk of poor ven­ti­la­tion, leaving the indoors feeling stale.

The designers of Texas’s first passive house acknowl­edged this is a complex problem requiring a detailed solution. A heat pump can adjust the indoor tem­per­a­ture as needed while an energy recovery ven­ti­la­tor draws in outdoor air, filters it, cir­cu­lates and flushes out stale interior air. Finally, a humid­i­fi­er manages humidity of occupant comfort.

A side benefit of passive design’s air­tight­ness require­ments is that homes often enjoy improved indoor air quality in com­par­i­son to tra­di­tion­al­ly designed houses. With regular fil­tra­tion, proper humidity and adequate fresh air exchanges, overall air quality is improved, making passive homes ideally suited for residents with allergies and envi­ron­men­tal sensitivities.

Are You Ready for Passive Design?

As the demand for passive design and Net Zero com­mu­ni­ties grows in Texas, it’s important to under­stand the standard require­ments and what it will take to go from concept to con­struc­tion. Bautex’s line of ICF alter­na­tives can help get you there. To find out how we can help, contact us today.