Building a passive house, a highly energy-efficient building, can be especially challenging when it's located on the water. The water environment brings unique challenges, including higher humidity levels and potential exposure to saltwater, that must be taken into consideration during the design and construction phases. However, with careful planning and consideration of best practices, it is possible to build a passive house that is both sustainable and comfortable on the water. Here are some of the best practices for building a passive house on the water:

1. Consider orientation and site analysis: The orientation of the building should take into account the prevailing winds, solar exposure, and views, to maximize natural ventilation and heating while minimizing heat loss and unwanted solar gain.

2. Use sustainable materials: Choose materials that are sustainably sourced, have low environmental impact, and are suitable for a marine environment. Consider using wood products from responsibly managed forests and low-VOC (volatile organic compound) materials to reduce indoor air pollution.

3. Implement a comprehensive insulation system: Insulation is a critical component of a passive house. Choose a high-performance insulation material, such as mineral wool or spray foam, and ensure that the entire building envelope, including the roof, walls, and floor, is properly insulated.

4. Install a mechanical ventilation system: To maintain good indoor air quality and to ensure that the house is well ventilated, a mechanical ventilation system with heat recovery should be installed. This will help control humidity levels, reduce the risk of mold, and improve air quality.

5. Choose high-performance windows: Windows play a crucial role in passive house design, helping to reduce heat loss in the winter and minimize solar gain in the summer. Choose windows with high U-values (a measure of heat transfer) and low solar heat gain coefficients (a measure of the amount of solar heat that passes through a window).

6. Incorporate shading devices: Shading devices, such as overhangs, blinds, and shading screens, can help reduce solar gain and improve energy efficiency. They can also provide privacy and protection from the elements.

7. Invest in renewable energy sources: Consider installing renewable energy sources, such as solar panels or a wind turbine, to generate your own energy and reduce your reliance on the grid.

By implementing these best practices when building a passive house on the water, you can create a highly energy-efficient and sustainable building that is comfortable to live in, reduces your impact on the environment, and saves on energy costs.

Sources:

• "Building a Passive House on the Water" (https://www.passivehouse.com/articles/building-a-passive-house-on-the-water)
• "How to Build a Passive House on the Water" (https://www.thegreenage.co.uk/how-to-build-a-passive-house-on-the-water/)
• "Building a Passive House by the Sea" (https://www.passivehouse.com/news/building-a-passive-house-by-the-sea)
• "Passive Houses by the Water: A Guide to Building Energy-Efficient Homes" (https://www.ecohome.net/guides/17071/passive-houses-by-the-water-a-guide-to-building-energy-efficient-homes/)