Maison Reciprocity, or Reciprocity House, is one of the entrants in this year’s Solar Decathlon Europe competition. In a nutshell, it is an energy-efficient, highly sustainable modular home, which aims to set the standard of low cost, and low impact building in the future. It is a joint effort between Appalachian State University and the French Université d’Angers, and one of only two entries into the competition by US teams this year.

Maison Reciprocity will be constructed using Binderholz Cross-laminated Timber, which is an engineered wood that is a great insulator, and can also carry heavy loads. The doors and windows of the house will be fitted with Eastman Chemical Company Heat Mirror insulating glass (IG), which has lightweight films suspended inside the airspace of the IG unit that work to create multiple super-insulating cavities, without adding extra weight. These cavities help prevent heat loss or heat gain. The center-of-glass thermal performance of these windows is up to R20 (.05 U-value), making them nearly as insulating as walls. The windows also block 99.5% of UV-rays.

The roof of Maison Reciprocity will be insulated using Atlas Roofing Corporation’s tapered and flat ACFoam-II roof insulation, which they chose because it can be used in most roof systems without the need for a thermal barrier, and because it resists heat transfer. For the rest of the insulation needs they chose Atlas Rboard (coated glass-mat faced board), and four types of Roxul insulation, which are made from natural and recycled materials and prevent moisture. Maison Reciprocity’s wall insulation system will be eight inches thick and made of polyisocayanurate (polyiso) and mineral wool.

The house will also have a green roof, which will be located beneath the rooftop-mounted photovoltaic array. In this way the vegetation will have an evaporative cooling effect on the panels, increasing their efficiency by keeping them at a stable temperature.

The house will be energy independent and will feature the Integrated Systems CHORD, which integrates the plumbing, heating, ventilation, and air-conditioning components in a single space. This efficient layout makes it easier to control and optimize all the different systems of the home.


The Solar Decathlon Europe competition will be held in Versailles, France from June to July 2014, and Maison Reciprocity is definitely a project worth rooting for.