Spain's cave houses can be described as the original 'green' home. Built into the rock the average ambient temperature usually stays around 20 degrees Celsius whatever the weather is doing outside.
Modern cave houses are also available. They are developed from existing derelict properties thereby minimising the amount of new building materials that are required. Wherever possible recycled materials are used including reclaimed beams and roof tiles.
'Cave houses make a significant ecological contribution. They are unobtrusive and blend with the landscape,' said a spokesman for Spanish Inland Properties.
This is just the kind of project that could attract a lot of new investors according to agents. 'Many developers are missing the very real point that increasingly consumers require environmentally-conscious homes with such things as solar power, eco-friendly water conservation methods and where the environment into which they are moving will remain unchanged and unspoiled,' said Mike Hamilton of Casas de Lorca in Murcia.
A recent poll by Tescocompare.com discovered that more British homeowners are considering making energy efficiency changes to their homes, thus it is not unimaginable that this environmental conscience will extend to holiday homes.
Mr Hamilton called on developers and investors to embrace this cultural change, working with government planning policies rather than against them. 'There is great opportunity to be had in terms of constructing fabulous real estate in an ethical manner that is hugely sought-after,' he concluded.
Some are moving in this direction. International architects Diseño Earle, based in Fuengirola, have designed what they believe to be the first 'zero carbon' footprint house in Andalucia.
The modern villa is also designed to be almost self sufficient in energy. By harnessing and exploiting natural elements the architects believe the home will be 80% more efficient that a similar sized house and have 75% less waste.
It is to be built using sustainable construction methods. 'As a company we are increasingly responding to the demand for modern sustainable design as clients become more knowledgeable about renewable energy products and their benefits,' said Michael Earle.