I've have a 3 story townhouse and have issue with the top floor being too cool in the winter and to hot in the summer. I'm beginning my search on the best approach to solve this issue. Are there any recommendations on ways to provide equal heating throughout the house? I've replaced all the windows and doors and working on the insulation to help solve some of these issues. The middle floor remains comfortable while the basement and upstairs remain cold. I looking to replace the heat pump and air handler before next winter. I'm thinking the best way is to set zones in the house.