Project goal

The aim of the project is the construction of our house.

The constraints are numerous and the main is money. It was therefore necessary to find ways to reduce costs, while ensuring a high quality of the building envelope. It was therefore necessary to compromise the architectural level, to have a home delivered without with windows, outside walls, roof and insulation but without everything else. A constraint for us is to have a home that is easy to maintain. That's why a lot of equipment are not purchased but manufactured by myself (solar water heater, home automation system).

We explored several ways but quickly it was clear that the passive house is the best solution to have a good comfort while maintaining the customary cost of the house down.

So we first sought land that fits our criteria for this house, namely ensure correct orientation and a sufficiently large area to not be crowded with neighbors. It was also necessary that the land was not too expensive. We found this gem at Oltingue, a small village of Sundgau, south of Alsace.

This land has many qualities

  1. South oriented
  2. Quiet neighborhood
  3. In a village, but located on a main road, so no problem to go to work even in winter.
  4. The distance to work is more important than before, but in return I do not have a red light.
  5. The shops nearby are numerous in this village, which avoids a lot of travel to the nearest city. There are the following services and businesses: All this reached by bicycle or on foot.
  6. Good ADSL internet connection a real 13Mb/s because the DSLAM is only just over 1km.
  7. The land is big enough but not too much (823 sqm), is almost square, and flat
  8. For the time being there will be only 2 direct neighbors. To the south, a farm with a meadow and cows. In the north, on the other side of the road there is also a house.
  9. The land price is still reasonable compared to other villages and towns around
  10. This development has relatively little impact because it is located within the village and it is therefore not strictly speaking a surface enlargement. Rather, it will allow to densify the village a little more.
  11. A river flows 100 meters from the land, but after gathering information from the village elders, the flood risk is very rare. Indeed, we are a few kilometers from the spring. But to further reduce these risks, we did not build a basement and we slightly built our home higher than natural soil.

We designed the house taking into account the land and the philosophy of passive and bioclimatic house:

  1. House faces south, so its largest wall facing south and the house itself as much as possible to the road on north to conserve space in the south.
  2. Compact House. We did a little twist to this principle since our house is not square but rectangular to maximize the window size to the south and especially to make the most of the land to the south which is the best part of it. Nevertheless, we do not have a complex shape that greatly increases the surface of walls in contact with the outside.
  3. Try to have as much sunlight as possible in winter (warm home) and prevent it from entering in summer (no overheating). For this, no north window, as few window as possible in the east and west, and large windows to the south. Large roof overhangs (80cm) protect from the summer sun. We also limited the roof window and we have only one.
  4. A maximum insulation, no thermal bridge
  5. A very good airtightness so as not to lose the gains of double flow heat recovery ventilation (ventilation risk of air short circuit if no good airtightness with a bonus bad air renewal)
  6. A powerful double flow heat recovery ventilation to recover the maximum amount of heat that comes for the renewal of the air coupled with an air quality sensor (VOC) to automatically vary the air flow.
  7. Even though the house is wood frame we still need some thermal inertia for comfort. This thermal inertia is provided by the concrete slab because its isolation is underneath. It will bring us an inertial mass of several tons. From our point of view, in a new house, the insulation of the concrete slab from below should be mandatory as the insulation from above has only disadvantages (thermal bridges around the perimeter of the slab in the case a concrete house with external insulation, loss of inertia of the slab in the case of wooden houses).
  8. A greywater heat recovery from the shower can reinject 60% of the energy in the hot water tank. This is a completely passive system without pumps or power consuming element.
  9. To complete heat recovery of greywater, a solar water heater provides the remainder.
  10. Heating and hot water are coupled in the same tank. The tank contains dead water. The hot water is heated in the tank via a coil (and the heat recovery on greywater upstream). Heating is provided by a hot water heat exchanger of 3kW connected on the ventilation system. The dead water in the tank is circulated through the heat exchanger via a pump. A 3kW electrical resistance is plunged into the tank. The solar 2000l tank is connected to the 300l tank.
  11. Triple glazing to minimize heat loss.
  12. The kitchen hood is also a problem because a recycling hood captures less fat and it will therefore settle on the furniture and go in the heat exchanger of the ventilation. Furthermore it is noisy. On the other hand an extraction hood will suck in large amounts of air and unbalance the double flow ventilation and vacuum lot of hot air to the outside without recovering this energy. For the moment I have not installed the hood but I fitted the extraction vent from the kitchen with a grease trap to prevent fouling of the exchanger.