Open windows on opposite sides of your home to encourage air flow by letting warm air out and cooler air in. Best to do overnight or early morning when it's cooler outside than inside. If you can only open one window, open internal doors to help the air circulate. If the temperature outside is cooler, put a fan by an open window to help draw in fresh air. Insulation can helpA well-insulated property can prevent unwanted heat from entering during the summer, while keeping it warm in winter.