alternative
benefit
blackboard
building
certificate
certified
chalk
chalkboard
consumption
cooling
costs
drawing
eco
ecological
economy
effective
effectiveness
efficiency
efficient
electricity
energy
environment
finance
gas
global
green
heating
home
house
household
improve
improvement
kwh
lighting
management
measure
money
oil
passive
power
reduce
reduction
renewable
resources
save
sketch
solar
technology
warming