Because the Earth's climate is currently changing. The world has a higher temperature than in the past, it also likely that in the future, the air temperature will be higher again gradually. Make your home temperature rise accordingly. Have applied the concepts derived from the rules of the r core are good and some of it is flowing into the system's working cool house invented. Experiments by guests at the end of the air pipes open down to 1 meter deep underground. Which relies on the principle of heat transfer and movement of air conditioning as temperatures inside the home model. By recording the temperature inside and outside the House, 1 hour for every model tested over 3 times amount averages. There is a difference of approximately 3 degrees Celsius. The cause is due to airflow from an underground pipe at a lower temperature to a higher temperature House