In Calgary, Canada it is freezing for a good portion of the year. Lighthouse Residential Studio Design built a duplex here focused on energy efficiency. Each unit is 2400 sq ft. Focus on energy efficiency started with increased insulation to keep the cold air out in the winter and inside in the summer. The floor plan allows open windows to maximize cross breeze forgoing the air conditioner in the cooler climate. All of the windows, doors, and appliances were also energy efficient.