Adding an air conditioner to the second floor of your house without covering the stairs or having an air conditioner on the first floor can present some challenges, but there are still some options you can consider:
Ductless Mini-Split System: A ductless mini-split air conditioning system can be an excellent solution for cooling a specific area or room on the second floor without affecting the first floor. It consists of an outdoor condenser unit and an indoor air handler that is mounted on the wall or ceiling of the room you want to cool. These systems are efficient, relatively easy to install, and provide individualized temperature control.
Portable Air Conditioner: If you're looking for a temporary or more budget-friendly solution, a portable air conditioner can be an option. These units do not require permanent installation and can be placed in the room you want to cool. However, you will need to vent the hot air out through a window or another opening.
Window Air Conditioner: While you mentioned you can't cover the stairs, you might still have other windows on the second floor where you can install a window air conditioner. This could effectively cool the room it's placed in without affecting the first floor.
Attic or Roof-Mounted Unit: If you have access to your attic or have a flat roof, you might explore the possibility of installing an air conditioning unit in the attic or on the roof to cool the second floor. This may require some modification to your home's structure and should be done by a professional.
Zoning: If you have a central air conditioning system on the first floor, you could consider installing a zoning system that allows you to control different areas of your home independently. This way, you can direct more cooling to the second floor when needed.
Window Fan or Ventilation System: While not an air conditioner, a window fan or ventilation system can help improve air circulation and provide some cooling benefits.
Before making a decision, consider factors such as the size of the room you want to cool, your budget, energy efficiency, and whether you want a permanent or temporary cooling solution. It's essential to consult with a professional HVAC contractor who can assess your home's specific layout and recommend the best option for your needs. They can also ensure proper installation, which is crucial for the system's efficiency and performance.