The study research how product design can influence and promote a transition to small sustainable homes through research and methods using Design for behaviour change. The study is based on previous research made on The Tiny House Movement (that started in the USA in the late 1990s) and examines the Swedish market for Tiny Houses through interviews with stakeholders in Sweden. The study is also based on theory from the areas of Sustainable development and Design for sustainable development. Through interviews, a target group of children was selected, and a list of requirements was written based on the theory and material collected from the interviews as well as from a supplementary investigation. The Design with intent method was used as a source of inspiration for the development of concepts, where two concepts were selected for further development and then analysed with the Harris profile method to find which concept best met the list of requirements. The final concept: a product intended to influence and promote children’s transitioning into small sustainable homes by allowing them to build different types of Tiny Houses on a small scale with drawings as guidance. The product, Tiny Tiny Houses, is intended to be used in the company of parents as an aid to teach learnings about alternative housing but is just as good for children to use on their own, with siblings, or in the company of other children. The product is similar to a backpack where the front is folded down to build Tiny Houses on a small scale with the help of building pieces similar to puzzle pieces that are pressed together. The product is easy to take out into nature to promote outdoor play. Nature is an important part of the concept as the child’s imagination together with nature will decorate the inside of the small houses.