08/19/2025
Can Thermal Mass keep you cool in the Texas heat? ☀️
A client once asked me if earth block walls really work in Texas, where the forecast usually reads hot, hotter, or hottest. It’s a great question!
The reality is that thermal mass only works when the design is done right. In places with hot days and cool nights, thick walls absorb heat during the day and release it after sunset, keeping interiors comfortable. But in climates like much of Texas, where summer nights stay warm and humidity lingers, mass walls can backfire and act like an oven, slowly cooking the inside of your home. 🧱
Here are 3 smart design tips to keep thermal mass working for you in hot texas climates:
1. Add exterior insulation so the walls work for you - Mass walls work best when they store heat in winter and block it in summer. A breathable insulation layer like rockwool or hemp-lime keeps hot air out and winter warmth in, while still allowing the walls to stabilize daily temperature swings. 🌡️
2. Be strategic with windows and shade – South facing windows can overheat interiors so they need overhangs designed to block equinox-to-equinox warm season sun, while letting in winter sun. West windows, which receive the hottest sun of the day, are best protected with porches, pergolas, or trees. 🌳
3. Plan for ventilation and mechanical cooling – On hot, humid, or cold days, mechanical systems like ERVs keep fresh air circulating while balancing temperature and humidity. Pairing ventilation with mechanical cooling in summer (and supplementary heat in winter) ensures interiors stay consistently comfortable. 💨
With the right details, earth block walls can keep you cool instead of cooked in hot climates!
Visit my website for more tips, link in bio. 🔍
Photos from my personal collection: West, Central, East and North Texas ⭐️