3D printing of cementitious materials offers i) faster and more accurate construction with potentially less waste, ii) a decrease in the amount of labor and consequently cost of labor, and iii) customization in design. We formulated an ultra-lightweight cement composite containing cenosphere, white cement, and white silica fume to be used in 3D printing. This mixture, which contains a significant amount of recycled material, achieves i) high-strength, ii) low density, iii) low thermal conductivity, and iv) high solar reflectance. We carried out optimization of rheological properties of this formulation to obtain a printable material that can reflect light and provide thermally insulating properties for warmer climates. Thermal and structural properties are characterized to demonstrate the performance of this mixture in comparison to other available alternatives.