'This hack is particularly useful if the air temperature is greater than skin temperature (32°C to 35°C), as it reduces the air temperature enough to allow body heat to dissipate again. Once the sun sets and the outside air cools, simply open the blinds to allow any trapped heat to dissipate.' When your home feels unbearably hot, it can be tempting to throw open every window in the hope of letting cooler air in. 'If the outside air is hotter than the air inside, opening windows simply draws that heat indoors and accelerates warming. 'Adding a second duct means that outside air is used to dissipate heat from the condenser, eliminating the suction effect.