using little electricity, gas, etc.
- These days, one of the most important considerations in building design and the choice of building materials is _______cy.
energy-efficiency (adj: energy-efficient)
15
material used to stop heat escaping
- In cold climates, it’s important for buildings to be well _______ and glass fibre is often used as roof _____.
insulated – insulation
15
not harmful to the environment
- Installing solar panels to cut down on the use of fossil fuels is one of the best ways to make your home _____.