There's also a cost issue: If you have a one stage furnace - your only option is a one stage AC (vs 2-stage or variable speed AC). You need to upgrade the furn

There's also a cost issue: If you have a one stage furnace - your only option is a one stage AC (vs 2-stage or variable speed AC). You need to upgrade the furnace/blower to take advantage of the more efficient AC model Mini-Splits are great but much more expensive to purchase (~4k USD per Unit which covers 400-500 sqft). They also don't heat as well as a traditional gas fired furnace. Heat pumps are probably the way to go in moderate climates but I haven't looked into them in much detail.