WaterNest 100: Giancarlo Zema's Floating Solar Eco-Home

Water Nest 100: A Floating Solar-Powered Home From Recycled Materials

The WaterNest 100 is a floating eco-home designed by Italian architect Giancarlo Zema for EcoFloLife, a London company that builds and sells floating residences. Shaped like a giant wooden pebble, it offers about 100 square metres of living space on calm water, is built from recycled laminated timber on a recycled aluminium hull, and carries 60 square metres of solar panels on its curved roof. Its designers say that up to 98% of it can be recycled.

Below we look at how it is laid out, what its solar roof can realistically supply, what “98%” actually refers to, and what anyone dreaming of a home on the water should think about first.

Who designed the WaterNest 100, and why

Giancarlo Zema runs a design group in Rome that has spent decades working on architecture on and under water: semi-submerged structures, marine parks, floating habitats, yachts and interiors. The WaterNest 100, presented in 2015, was developed for EcoFloLife as an “ecological floating habitat”, a self-contained unit that can be placed on a river, lake or sheltered bay.

The idea behind it is that floating buildings can make use of water space instead of land, sit lightly on their site and be moved or removed without leaving foundations behind. With rising sea levels and crowded waterfront cities, that appeal has only grown since.

Render: Giancarlo Zema Design Group

Size, shape and layout

The unit is round, about 12 metres across and 4 metres high, giving roughly 100 square metres of floor space. Large windows wrap around the sides, with small balconies built into the curved shell, and skylights let daylight into the bathroom and kitchen. Inside, curved wooden partition walls follow the shape of the hull.

As a home, the space fits a living room, dining area, bedroom, kitchen and bathroom. The images released by the designers show furniture chosen to echo the rounded shell, with built-in oval shelving, low curved armchairs and a bed that seems to grow out of the floor.

Solar panels on the roof can generate 4 kWp.

Render: Giancarlo Zema Design Group · The bedroom, with furniture shaped to follow the curve of the walls.

The bedroom is spacious and the furniture chosen to display the room really matches the curvature of the Water Nest and ties everything in. All furniture is from EcoFl

Render: Giancarlo Zema Design Group · The dining area sits against the long window wall, with views across the water.

The dining room has a perfect view of the outside and plenty of light. It is a perfect place for a meal or for some quick office work.

Render: Giancarlo Zema Design Group · The living room, with lounge chairs and built-in shelving.

These are computer renderings rather than photos of a finished, lived-in home, so they show the design intent. A real installation would add the clutter of daily life, mooring lines and services.

The solar roof: what 4 kWp really means

Render: Giancarlo Zema Design Group · Around 60 square metres of thin-film solar panels cover the roof.

The top of the shell is covered with about 60 square metres of amorphous (thin-film) photovoltaic panels rated at 4 kWp. The “p” stands for peak: it is the output the panels would deliver under standard test conditions of strong, direct sunshine. Real output over a day is much lower, because the sun is not overhead all day, clouds pass, and panels lose efficiency when they get hot.

A useful rule of thumb is that each kWp of solar produces roughly 800 to 1,500 kWh a year, depending on location. That suggests a 4 kWp roof might supply something like 3,000 to 6,000 kWh a year, from cloudy northern Europe at the low end to a sunny Mediterranean lake at the high end. That is in the range of a typical small household's electricity use, though not necessarily on every day or in every season, so most installations would still need a battery or a connection to shore power.

The choice of amorphous panels explains the large area. Thin-film panels convert a smaller share of sunlight than standard crystalline panels, which is why 60 square metres yields only about 4 kW at peak. Their advantage is that they are flexible and lighter, so they follow the curved roof without heavy frames.

Recycled or recyclable? Sorting out the 98% claim

Many articles say the WaterNest is “made from 98% recycled materials”. The designers' own wording is a little different: the unit is built from recycled glued laminated timber and a recycled aluminium hull, and up to 98% of it is recyclable thanks to its materials and production methods. In other words, it uses recycled material, and most of it can be recycled again at the end of its life.

Glued laminated timber, or glulam, is made by bonding layers of wood under pressure, which gives fewer defects and more predictable strength than solid timber. Aluminium suits a hull because it resists corrosion, needs little maintenance and can be melted down and reused many times. The interior walls are curved wood treated to cope with damp conditions.

For climate control, the design relies on natural micro-ventilation through grilles in the ceiling and floor, plus an air conditioning system with automatic temperature control. Smart-home controls manage lighting, blinds, sound and energy monitoring. EcoFloLife presents the whole package as a low-consumption habitat.

Not only a home: bars, offices and shops

Render: Giancarlo Zema Design Group · One suggested layout turns the interior into a lounge bar.

Because it is essentially an open, round room on a floating base, the same shell can be fitted out for other uses. The designers show it as a lounge bar and suggest offices, restaurants, shops or exhibition spaces. A group of units could form a small floating resort or waterfront village, something Zema has also explored in later concepts.

This flexibility matters commercially. A floating bar or gallery on a city canal or marina may be easier to approve and more profitable than a private home, and could help prove the technology before more people choose to live on the water.

Render: Giancarlo Zema Design Group · Lit from within at night.

Thinking about living on the water?

The WaterNest is designed for calm water only: rivers, lakes, sheltered bays, atolls and quiet sea areas. Open coastlines with large waves are not suitable. If the idea of a floating home appeals to you, a few practical questions come before choosing a design:

Where can it be moored? Most places require a licensed mooring or berth, and the rules for living aboard differ from country to country and even between marinas.
How will services connect? Fresh water, waste water and electricity need safe connections or self-contained systems. Waste water in particular must never go straight into the lake or river.
What about insurance and maintenance? Hulls need regular inspection, and floating homes may be insured differently from houses or boats.
How does it handle weather? Ask about wind loads, ice in winter, and how the structure copes with changing water levels.

Pricing and availability for the WaterNest 100 were not widely published, so anyone interested should contact the designers or the manufacturer directly.

Watch the designers' video presentation of the WaterNest 100: