Yes, it is possible to cool both the upstairs and downstairs areas of your home using two separate HVAC units with separate thermostats. Here are a few options you can consider:
Zone Control System: A zone control system allows you to divide your home into separate zones and control the temperature independently in each zone. With this system, you can have separate thermostats for the upstairs and downstairs areas. The zone control system uses dampers in the ductwork to direct airflow to specific zones as needed, providing individualized temperature control.
Adjusting Dampers: If your HVAC system doesn't have a zone control system, you may still be able to adjust the airflow manually by adjusting dampers in the ductwork. Some homes have manual dampers that can be opened or closed to control the airflow to different areas. By partially closing the dampers in the downstairs ducts and opening the ones upstairs, you can redirect more cool air to the upper level when needed. However, this option requires access to the ductwork and an understanding of how to properly adjust the dampers.
Portable Air Conditioners or Fans: If you only occasionally need to cool both areas simultaneously, you could use portable air conditioners or fans in the upstairs rooms to provide additional cooling when guests are present. Portable air conditioners can be placed in individual rooms, providing localized cooling. Fans can help circulate the cool air from the downstairs to the upstairs areas.
It's worth mentioning that the best approach may depend on the specific layout of your home, the capacity of your HVAC systems, and your budget. Consulting with an HVAC professional can help you determine the most suitable solution for your specific needs and provide guidance on the installation or adjustment process if necessary.