 Number two, three years ago, more than 2.5 billion hours of labor were lost due to heat exposure in the agriculture, construction, manufacturing, and service sectors. A separate report found that health care costs from extreme heat amount to an estimated $1 billion every summer. The average cost of electricity bills in the summer has increased by 51% over the past 10 years. And if you live somewhere without air conditioning, experts recommend opening up your windows at night and closing them as afternoon heat.