environmental
appliance
architecture
blue
building
chart
class
classification
comparison
concept
conservation
conserve
construction
consuming
consumption
cost
cottage
diagram
ecological
ecology
economy
effective
effectiveness
efficiency
efficient
electric
electricity
energy
environment
friendly
green
heating
home
house
level
norm
pollution
power
problem
protect
protection
rating
real estate
renovation
residential
rules
save
saving
sky