Thai Villa Holds 26°C Without Air Conditioning, Thanks to Its Zig-Zag Roof

A family villa in northeastern Thailand holds an average internal temperature of approximately 26°C without air conditioning, its architects report. Khao Yai Mountain Grounded Villa, designed by Bangkok-based practice HAS Design and Research, sits in the green landscape of Khao Yai, on the edge of the national park, and it doesn't exactly hide.

The house is crisp white, and its jagged zig-zag roofline pops against the leafy surroundings. The practice's founders, Jenchieh Hung and Kulthida Songkittipakdee — both 2022 Wallpaper* Architects Directory entrants — led the design for what they call a countryside family retreat.

What drives the design?

The starting point is philosophical as much as formal. The architects say the dwelling responds to 'the philosophy of the Sufficiency Economy, initiated by Thailand's King Rama IX, which advocates self-reliance through sustainable, environmentally conscious living.' Old and new building methods merge here, creating generous living space while respecting the site's resources.

The passive strategies are concrete:

• The L-shaped footprint references the local agricultural vernacular's courtyard arrangement, helping control sun and airflow — shielding some areas while opening others to the outdoors.
• Maximised sun exposure and ventilation maintain a comfortable internal environment.
• A harvesting system collects and reuses rainwater to irrigate the garden.

Why the zig-zag roof?

The playful geometry isn't arbitrary. The jagged roofline abstractly echoes the outline of the region's surrounding mountains, visible through the home's large openings. Those shapes cast pixel-like mountain shadows across the floor and reflect on the extensive glazed surfaces.

The architects say the approach 'draws inspiration from the dramatic silhouettes of Nang Yai, Thailand's traditional shadow puppet theatre. While Nang Yai is one of Thailand's most celebrated cultural traditions, its visual language has never before been translated into contemporary Thai architecture. Here, the project reinterprets this cultural heritage through architecture, transforming light, shadow, and landscape into an immersive spatial experience.'

How does the house work inside?

The interior is a flowing open plan built for flexibility — gathering, communication, yoga, meditation and everyday activities all fit within it. Auxiliary spaces discreetly tuck in a tatami room, music room, water closet, kitchen and wine cellar. One arm of the L holds the social areas; the other contains the two en suite bedrooms.

What does this change for tropical residential design? The architects argue the project shifts the conversation from plan to envelope to roof. They conclude: 'More than introducing a new residential typology, the project redefines the role of the villa by shifting its architectural paradigm from Le Corbusier's free plan to Mies van der Rohe's transparent façade, and ultimately to the roof as a new architectural manifesto of shade and shadow. In doing so, the project proposes a new paradigm for contemporary tropical living, where wind, rain, light, landscape, culture, and nature become the primary generators of architectural space.'

If that manifesto travels, the roof — not the machine — becomes the climate instrument.