Sleephellingstraat - Passive House Retrofit
Sleephelling is a monumental building block in Rotterdam counting in total 14 households and 16 units for social retreat. Good quality of indoor climate, comfort, daylight and spacious rooms were important design issues. The monumental front facade is insulated from the inside, while the garden facade is insulated from the outsi. Original window frames were preserved, and a extra frame is placed inside. This project was first to receive a retrofit passive house certificate in the Netherlands.
An extra investment of €30.000 for the energetic upgrading of houses in the Sleephellingstraat to passive house standard lead to a significant increase of the market value of the property. One house was sold after retrofitting for €270.000. One year later this property (by this time equipped with an additional bathroom and luxe kitchen) was resold for €370.000.