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Zero-Carbon Wonder on a Greek Island: This Small House Makes Architecture a "Healer" of Nature

Release Time:

2025-09-11

A Zero-Carbon Wonder on a Greek Island: This Small House Makes Architecture a "Restorer" of Nature

Under the azure sky of the Aegean Sea, a residence seems to naturally grow from the hillside of Syros Island, Greece, closely embracing the earth.

Horizon House | Horizon House

This 230-square-meter residence designed by ONUS Architecture Studio in Athens is far more than just a house. With "regenerative architecture" as its soul, it confronts the fragile island ecology and the challenges of future living—not only pursuing net-zero energy consumption but also striving to be an active participant and restorer of the ecosystem.

Born from the land, returning to nature

The building is cleverly half-embedded into the hillside terrain, blending with the mountain, humbly disappearing into the landscape while gaining natural insulation and thermal protection. Local stone is extensively used for wall construction, supplemented by reclaimed wood and exposed concrete, forming a rustic, low-carbon local architectural language. The roof is covered with greenery, serving not only as a rainwater collector but also as a natural insulation layer and a miniature ecological regulator.

Sunlight, breeze, geothermal energy:

The self-sufficient energy code

The house is carefully oriented southward to maximize sunlight and magnificent sea views; the north side is relatively enclosed to effectively resist strong winds.

· Wind and geothermal energy combined: Micro wind turbines paired with a geothermal system meet the entire house's energy needs.

· Water cycle closed loop: " The "blue roof" system combined with greywater recycling achieves efficient closed-loop water resource management.

· The power of nature: Cleverly arranged skylights and operable windows allow breeze and sunlight to flow freely, making summer comfortable even without air conditioning.

Designing not just a residence,

but an ecosystem

The landscape design selects local drought-resistant plants that silently protect the soil, attract pollinating insects, and quietly optimize the microclimate. The L-shaped pool surrounding the building is not only a leisure spot but also a cooling interface that enhances the dialogue between the building and the environment.

Interior space:

Warmth in simplicity

From the living room to the bedroom, the space stretches along the horizon. Interior materials are extremely simple, allowing the natural textures of stone, wood, and concrete to emerge naturally. Courtyards, terraces, and shaded corridors blur the boundaries between indoors and outdoors, creating a living experience that flows continuously and freely.

[2025 Architizer A+ Awards Global Best Sustainable Residence]

" Architecture should not just be a container; it can be a living unit that restores ecology.

Horizon House Clearly telling us: architecture can not only be "low-carbon" but also actively "regenerative"; not only a model of "energy saving" but also a future living solution that coexists and gives back to nature.

Horizon House

Siros, Greece

ONUS Architecture Studio

A net-zero residence embedded in the Cycladic terrain, blending architectural minimalism with regenerative design strategies

Athina, Greece, 2025-08-05 -

Located on a sloped site in Syros, Horizon House is a net-zero energy residence designed by ONUS Architecture Studio. Rooted in the Cycladic landscape, the project prioritizes energy autonomy, ecosystem restoration, and circular resource use. The semi-subterranean design minimizes visual impact while maximizing environmental performance, offering a case study in regenerative architecture for island environments.

Winner of the 2025 Architizer A+ Award for Best Sustainable Residential Project worldwide, Horizon House by ONUS Architecture Studio is a recognized example of regenerative architecture. Selected by an international jury, the residence was honored for its approach to off-grid energy, site-responsive design, and low-impact construction on an island terrain.

A reinforced connection to place

Located in Syros, Greece, Horizon House sits on a steep slope overlooking the Aegean Sea. The 230-square-meter residence is partially embedded in the earth, allowing the landscape to shape both the form and performance of the building. Stone excavated from the site is used for structural walls and cladding, reinforcing the house's material connection to place. The design employs reclaimed wood, raw concrete, and native vegetation, resulting in a low-carbon, locally-grounded palette.

The house unfolds along a linear axis parallel to the horizon. Interior spaces face south, offering uninterrupted views, while maximizing passive solar gain. The more sheltered northern fa ç ade reduces exposure to prevailing winds and supports thermal comfort. An L-shaped pool defines the outdoor space and contributes to passive cooling, while visually linking the residence to the surrounding topography.

Bioclimatic strategies are central to the design. Deep-set openings, operable windows, and three skylights enable cross-ventilation and natural lighting, reducing the need for mechanical systems. During summer, thermal mass and air circulation maintain stable indoor temperatures.

A fully energy-autonomous project

Micro wind turbines harness the island’s constant wind, while a geothermal system provides heating and cooling. The 300-square-meter green roof collects rainwater, which is filtered and stored through a blue roof system. Greywater is also treated and reused, minimizing waste and enabling off-grid operation.

A landscape design supporting environmental regeneration

Native plants—adapted to the Cycladic ecosystem—were selected to enhance biodiversity, attract pollinators, and stabilize soil. Strategic placement of trees and shrubs provides shading and protection from wind, improving the microclimate around the building. These interventions contribute to long-term soil health and water retention, supporting a self-sustaining ecological balance.

Simplicity and continuity

Inside, the spatial layout emphasizes simplicity and continuity. Living and sleeping areas are organized around natural light and views, with minimal finishes that allow the textures of the materials to define the atmosphere. Transitions between indoor and outdoor space are fluid, with courtyards, terraces, and shaded verandas extending the living experience outward.

Horizon House reflects an approach to regenerative design that prioritizes restoration over consumption. The residence is conceived not only as a shelter, but also as a system that supports environmental and human well-being. It demonstrates how architecture can become part of a broader ecological infrastructure—supporting natural processes while providing a refined and resilient living environment.

By integrating renewable energy, water reuse, local materials, and ecosystem-based strategies, Horizon House offers a model of sustainable living that adapts to place and climate. Its quiet presence in the landscape reflects a commitment to architecture that works with, rather than apart from, the land it inhabits.

About ONUS Architecture Studio

ONUS Architecture Studio is an Athens-based architectural team committed to sustainable and regenerative design. The studio is steadily expanding and has received multiple international awards and distinctions, including the Architizer A+ Award in 2025.

ONUS brings expertise in circular construction, passive house principles, and ecosystem-based planning. Each project reflects a careful balance between environmental performance, material clarity, and spatial intention—exploring how architecture can actively contribute to both ecological and social systems.