Underground houses may be known by different names - green home, earth integrated home, earth contact home, earth sheltered home, hobbit house and many more - but they all have one thing in common: they offer sustainable benefits that can save 50 to 75 per cent on heating and cooling costs compared to traditional dwellings.

While many types of structures are now considered underground homes – the term applies to buildings with one or more walls below the earth’s surface – the earliest underground homes were natural caves or caverns where primitive people used to live. In recent years, architects and designers have been studying…