We do more than just build.

Building Eco Chalets in the French Alps

We create AA energy rated eco chalets using our expertise in sustainable systems and carefully thought-through holistic detailed design.


We build eco-friendly chalets that work in equilibrium with their surroundings.

Using thermal engineering we create a detailed plan to ensure the building is as low impact as possible, achieves an AA energy rating and conforms with French environmental regulations RE2020. By harnessing the natural heat energy from the ground and the air, we can cool the building in summer and heat it in winter using minimal electricity.

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interior of a beautiful, open plan bespoke eco chalet construction


How does a SIP house harness natural resources in order to minimise its impact on the surrounding environment?

ECSUS Design Ventilation diagram showing the how SIPs are integrated into their passive homes

The panels create a fully airtight structure which is highly insulated and loses minimal heat. When combined with other eco systems our chalets are almost passive with minimal heating bills and energy usage. The SIP structure itself has a negative carbon footprint due to the manufacturing process and the use of recyclable materials. The EPS foam insulation has zero Ozone Depletion Potential and does not contain or release gases harmful to the environment.

The OSB on the outside of the panels is made from fast-growing sustainable forests and, because the panels are structural and significantly stronger than traditional timber frame, using SIPs significantly reduces the amount of timber needed. We use NEOPOR panels as this type of EPS insulation, which contains high-purity graphite particles, uses fewer raw materials which reduces the structure’s embodied carbon.

Read more about SIPs here.

ECSUS Design Ventilation diagram showing the how their heat recovery systems are integrated into their passive homes

We use these systems, in conjunction with heat recovery, to control and circulate fresh air, through a system of ducts and fans. Homes relying on ‘natural ventilation’ like window trickle vents and holes or cracks can retain stale, humid air and lose heat. Humid air heats more slowly than dry air, meaning more energy is used to heat the house, and if the heating is on too much it can cause low humidity which also adversely affects health.

A mechanical ventilation system efficiently extracts humid air and circulates clean, dry air which can be heated faster. On the other hand, ventilating by opening windows, for example, results in the loss of more than 50% of heating energy.

ECSUS Design Ventilation diagram showing the how their heat recovery systems are integrated into their passive homes

Traditionally, outside air enters a building directly through window vents or holes and cracks and in winter (especially in the snowy mountains) that cools the ambient indoor temperature dramatically, meaning the heating system is always working hard to keep you comfortable. On the flip side, the heat in the air extracted from the house, from shower rooms or kitchens, is lost the moment it is expelled outside.

Heat recovery systems actually use the heat from the outgoing air to warm up the incoming air, leaving the house with both a constant temperature and fresh air – while using hardly any additional energy. The two streams of air do not mix, so the stale air does not contaminate the fresh air – only the heat is exchanged. All our chalets have built-in heat recovery because it really is a no-brainer when it comes to the environment, reducing energy usage and bills.

ECSUS Design Ventilation diagram showing the how the Air source heat pump is integrated into their passive homes

The renewable, low carbon alternative to traditional high carbon fossil fuel gas or oil-powered systems, these units heat your hot water and underfloor heating with minimal environmental impact and cost. The outdoor unit extracts heat energy from the air (even in extremely cold temperatures of – 20degrees) and transfers it to heat the water. Working much more efficiently, it will provide gentle heating over longer periods rather than quick boosts of heat on demand – ensuring a consistent perfect temperature and low running costs. It can also be used to cool the home in summer.

The system can deliver up to three times more heat energy to a home than the electrical energy it consumes, as it transfers existing heat rather than converting it from a fuel, like combustion heating systems. A gas boiler will produce less than 1kW of heat energy for every kW of gas consumed. A heat pump on the other hand harvests renewable energy from the outdoor air so will produce 3 or more kW of heat energy for every kW of electricity consumed, making them 3-4 times more efficient than gas boilers. The systems we incorporate use natural CO2 refrigerant, tested to have an Ozone Depletion Potential of zero and a Global Warming Potential of one. We use heat pumps with A++ ratings, meaning ‘extremely energy efficient’, under the European regulations for energy labelling and eco design.

ECSUS Design Ventilation diagram showing the how the underfloor heating is integrated into their passive homes

Pipes are laid under the floor and insulated, and the water they contain is gently heated to maintain a consistent temperature evenly distributed in the home. Gently warming the large area of floor space is up to 40% more energy efficient than quickly delivering a high temperature to a small traditional radiator to heat a room. This is optimised when the underfloor system is used in conjunction with an air source heat pump and in a SIP building which retains the heat. Heat is also stored in the screed or concrete in which the pipes are embedded.

Underfloor heating is usually only needed at ground floor level in SIP homes as the building is so well insulated. The air that is circulated from underfloor heating is fresher and cleaner than air that comes into contact with radiators. Along with warm air, water-heated radiators circulate moisture which can result in damp and mould forming, reducing the air quality of your home. On the other hand, electrical resistance radiators actually dry the air out completely, which can adversely impact health.

ECSUS Design Ventilation diagram showing the how the canadian well is integrated into their passive homes

A passive technique to regulate the temperature of a building using the earth’s natural geothermal energy. Instead of outside air directly entering the building’s MVHR (Mechanical Ventilation Heat Recovery) system, it is first drawn in through a long pipe, which starts just above ground around 40-50 metres away from the house and then runs underground all the way to the mechanical ventilation central unit. The pipe is buried to a depth of below 1.4 metres, where ground temperature is constantly 12-14 degrees C year-round, even in the mountains in winter, and as the air travels along it is heated completely naturally.

Consequently, the air is already pre-heated when it enters the system, and energy bills are greatly reduced. The pipe is dug in at a downwards angle so that condensation runs off at the end, preventing mould and humidity and ensuring clean, fresh air for the inhabitants. In summer the warm outside air is drawn through the pipe in the same way and the ground temperature actually cools the air coming into the building. A system of grills and filters at the air intake terminal ensures only healthy air is sucked in.

ECSUS Design Ventilation diagram showing the how their triple glazing contributes to their passive homes

The higher insulation properties of triple glazed windows allows much less heat to escape, reducing the amount of energy needed for heating or cooling the home. In fact, double glazed windows can lose around twice as much heat as triple glazed. Insulation is incorporated into the frame, and we also ensure windows and doors are completely sealed so air cannot leak through gaps in the frame or openable section.

Triple glazing is very effective at reducing noise transmission as well as solar gain in summer. If necessary a solar reflective coating can be added. This can help lower a building’s energy costs, reducing the need for artificial lighting and air conditioning by letting in most of the natural daylight but only around a quarter of the solar heat. In such well insulated SIP homes it is important not to overheat while allowing unobstructed views of the stunning mountain scenery, especially in chalets with large south-facing windows.

ECSUS Design Ventilation diagram showing the how effective shutters & blinds contribute to their passive homes

External shutters and blinds over window openings can help insulate buildings in winter whilst ensuring they do not overheat in summer. Electrically operated Venetian blinds are the most versatile solution allowing natural daylight into a room whilst obscuring direct sunshine reducing the need for artificial lighting. They can also be closed completely to provide black-out conditions.

ECSUS Design Ventilation diagram showing the how solar panels are integrated into their passive homes

Convert the sun’s energy using either solar collectors to heat water or photovoltaic panels to generate electricity. Electricity generated by panels can be sold back to the national grid or stored within batteries for use at night.

Forest full of trees


We create homes that work for you as well as the planet

French environmental regulations RE2020 are gradually coming into force, requiring carbon impact assessment and life cycle analysis of new builds. Our properties already surpass government standards and achieve AA ratings for energy and emissions, resulting in significant savings on future household heating bills.

Healthy LIVING

The benefits of spending time outdoors shouldn’t be lost when we enter our home

Our mission is to enhance the quality of life for clients by prioritising healthy living conditions. Using an airtight SIP shell allows us to control indoor air quality, using mechanical ventilation and heat recovery systems, and engineer a building that’s healthier to live in.

Healthy LIVING
Beautiful interior shot of living room with fire
Forest full of trees

our pledge

Building a sustainable future

At ECSUS Design we’re not just about building homes; we’re about building a sustainable future. We are proud to support Montagne Verte, a Haute Savoie non-profit public benefit association working to providing solutions for mountain residents, visitors and businesses alike, to minimise their environmental impact. Funded by members, the association employs a Sustainability Director to work full time on all things climate related.

As a member of Montagne Verte, we are contributing to the important process of turning Morzine and its neighbouring towns into a more sustainable resort, to ensure we can all enjoy the mountains for generations to come. Together we make a collective, and a collective can make a difference.

Assisted and funded by ECSUS Design, the Montagne Verte Green Pages guide to grants (2021) for eco construction and renovation is available to download.

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Join us on our mission to create high quality, low environmental impact homes in the beautiful surroundings of the Haute Savoie. Together we can make your eco ski chalet dream come to life.