Evaluation of Energy Efficiency, Indoor Air Quality and Sustainability Testing of Green Buildings in Nairobi, Kenya

Abstract

Green buildings should save energy, be environmentally friendly and offer healthy and safe indoor conditions for the occupants. To reduce energy consumption and improve indoor air quality in buildings require innovative ways. The study aimed to establish green buildings’ impact on energy efficiency and indoor health environment. Four buildings, two green (GB1 and GB2), and two non-green (NGB1 and NGB2) at Strathmore University and CUEA were used. Energy efficiency was investigated using power bills from Kenya Power for the year 2018 whereas buildings air change rates were determined using metabolic CO2 as a tracer gas and using the tracer gas method to calculate the air change rate. CO2 concentrations were monitored over a period of 4 months using HT-2000 CO2 meters. Checklists by GreenMark Standard were used to assess the green buildings’ energy and indoor health environment sustainability. The results show statistical significant difference in energy consumption between green and non-green buildings (p-value= 1.18×10-12) as the green buildings consume 40% less energy. Green buildings had between 80% to 86% better air change rates than non-green buildings. An indication that the probability to inhale contaminated air was higher than 0.8 in non-green buildings. There was significance difference in air change rate between green and non-green buildings (p-value=0.02 for buildings at Strathmore University; p-value= 0.002 for buildings at CUEA). Using the GreenMark checklist, GB1 scored 68% whereas GB2 scored 85% for health indoor environment category. For Energy efficiency category, GB1 scored 87.5% while GB2 scored 50%. Therefore, policy on green building technology should be developed by government and construction sector to reap the energy efficiency and quality indoor environment benefits