The summer 2013 tested our Molehouses with external temperatures of 40°C almost every day. As a consequence, we found out that Molehouse does not need any cooling. It is impossible to overheat the house thanks to its robust construction and the surrounding soil temperature of about 10 °C. The indoor temperature reached 26°C with no air-conditioning, no external blinds, no aeration in the night, and windows with no sheltering, which was 14°C cooler than outside at the same time. One would rather feel cold than warm (NB: it was measured when the house was still in construction). With night ventilation, outer shielding windows or overhanging roof, the temperature was measured max 24°C. Therefore, there is no need for air-conditioning and we do not even design it for our Molehouses.


In winter, the heat recovery system is almost required for passive houses since up to 30% of the heat escape through ventilation. However, this is the case of ordinary houses. Molehouse is different. Even if cold air enters the house, it immediately heats up to the indoor temperature thanks to the massive accumulation. As a consequence, Molehouse benefits from a stable indoor temperature. The energetic balance is almost zero because the energy is constantly supplied.

The heat recovery system is installed in Molehouses only because of greater comfort during ventilation. In this way, residents of the house do not ever have to worry about the supply of fresh air.

Indoor temperature of Molehouse


Have a look at our accomplishments.


We disposed of a north-western slope and wanted a Molehouse. We had no idea it could have facade on two sides. Thus, we benefit from privacy as well as sunlit home.



We want a house that makes us self-sufficient, a house, where we will be able to grow vegetables even in winter. We want a house, of which it will be easy to care.



After a long reflection, we chose Molehouse Pod Lesom (“Below the Forest”), because it meets our two critical requirements – self-sustainability and comfort.