The photovoltaic system plays an essential role in this building, not only for the production of electricity (see 3) but one of the strategies of this building in winter is to recover and use the heat produced in the PV system and used in winter time, according Figure 4. There are several possible situations which can be used in this system.

In winter the user during daytime, open the vents which connect the interior of the building with the space between the PV and the wall. By natural convection, the air enter through this vent, is heated and return to the building, during nigh time to user has to close this circulation closing the vents.

Figure 5, presents the measured temperatures in the vents (upper and lower vent) as also in the room, and in synthesis it is possible to see that in an winter day the incoming temperatures from the PV system are around 30°C in a sunny day and could achieve the 37°C.