Retreat was his first stab at a "smart house." Automated with a thoroughly integrated computer system that regulates and maintains every aspect of the house, including its energy in/out. By adopting the same kind of solar converters that had powered his armor for years, except on a much larger scale, Stark made the house to function totally off-grid (independent of local power utilities). Sunlight is used to illuminate every inch of the house. Patented fiber-optic tubes act as dimmer switches to keep rooms from getting too bright. At night, a single light source is beamed throughout the entire home via the same tubes.
The environmental-friendly design continues in the water system. Water is collected from the atmosphere and stored inside of a closed system--purified and recirculated (Stark did start with a surplus amount of water, but now recycles). Although the outdoor pool presents challenges, atmospheric moisture collectors ensure that Retreat needs no outside water source.
The rest of the home is relatively conventional--well, conventional for a billionaire playboy engineering genius. As mentioned the solar home has a lot of glass. And with an atrium at the home's core, an expansive dining room opens out to an awesome balcony overlooking the beautiful ocean, there's no shortage of great views. Tony's solarium/bedroom on his top floor also allows him to take advantage of the spectacular sunrises/sets. (His bedroom features a computerized closet, capable of laying out his clothes.)
The large gourmet kitchen is fully automated. And although Stark employs a part-time housekeeper, the kitchen systems can prepare food as needed. Keeping with his eco-conscious design, Stark uses propane for some cooking applications rather than conventional gas.