This study investigates the effect of tree-shading on energy demand in two similar buildings. Outdoor and indoor air temperature was measured simultaneously for a period of 6 months. Five different base temperatures ranging from 20 degrees C to 25 degrees C were chosen and used to calculate cooling degree-days. Degree-day and cooling/warming rate methods were used to estimate cooling energy requirements for the two buildings. Indoor and outdoor cooling degree days were observed to be more for the un-shaded buildings compared to the tree-shaded one. Indoor warming and cooling rate show that the un-shaded building warms earlier and faster than the tree-shaded. Results indicate that tree-shading can save up to 34,500 NGN (US$218) on energy costs. The study shows the role of greening in reducing energy demand in buildings. (C) 2014 Elsevier B.V. All rights reserved.