These ducts tend to be made of metal and run along the floor joists which means that you can only see them when you are in the basement.

• 比如能源部和佛罗里达州合作设的“零能耗住宅”、 “太阳能住宅”等，通过利用佛罗里达地区充足的太阳能和采取建筑节能措施，让住宅不再需要使用外来能源。