I am moving to a house that has a propane forced air furnace. However, there is no central air installed. My plan is to simply get an HVAC company to install it into the existing furnace and use the duct work. Is it that simple?
It can be relatively simple. They have to install a condenser unit to the top or the side of the furnace (depends if you have an upright or horizontal furnace) and run copper lines to an outside compressor/fan unit. Power has to run to the outdoor unit.
If the existing furnace is relatively new then it should not be a problem. If it is older then they will probably want to replace both units at the same time.