"Energy consumption continues to rise, but there is no shortage of sunshine!" Jeroen Veth - Trinergie Project Leader

Jan Borgman and Erna Roeterdink’s farm is called 't Spieker (which is also the name of their company), and is located at Vierakker in the Achterhoek region of the Netherlands. This is a very special property, of considerable historical value. The manorial farm dates back to (the second half of the sixteenth century) around 1600. It was used for the storage of grain, but the discovery of hearths suggests that 't Spieker was also inhabited. The name 't Spieker is derived from the Latin word spicarium, which means grain repository. 't Spieker is also called 't Spijker, 't Olde Spieijker, or 't Hoge Spijieker.

't Spieker was built at ground level. A moat was then dug around it and the excavated sand was thrown against the wall, creating a kind of cellar. The walls get thinner with each successive storey. The thickness of the walls ranges from 110 cm in the cellar to just 30 cm in the top storey. The entire building is constructed of kloostermoppen (a type of brick used in the Middle Ages). The pigeonholes at the top of the house are currently inhabited by owls. 't Spieker was comprehensively renovated in around 1960.

Jan and Erna live at the 't Spieker manorial farm together with their sons Dirk and Tim.