Evaporative cooling contributes to significant air leakage which in turn affects heating and cooling energy efficiency. In Melbourne, there are 176 hours with 30˚ C plus temperatures and 1336 hours with less than 10˚ C temperatures in 1 year. With these numbers should we be worried about energy efficient cooling or energy efficient heating in the southern parts of Australia? Efficiency Matrix goes over the negatives of having evaporative cooling installed. Evap cooling is a serious contributor to air leakage in homes, and although it may save you money, cooling in summer, it can be useless on humid days and cost a lot of money in heating during winter. Cooling an individual room with an inverter split system may be a more economic solution and spending time on improving the air tightness and insulation effectiveness of the building envelope, which will benefit summer and winter energy consumption.