Will my AC unit cool my whole house? Jessica 29 June 2021 01:07 Updated An air conditioner will only cool down the room it is placed in. Related articles What size Air Conditioner shall I get? Can I use a portable air conditioner in a room without a window? How often do I need to drain the watertank? Does my AC unit double up as a heater in the winter? How do I clean my dehumidifier?