Mitsubishi Mr. Slim Dual Split Heating and Cooling
We have 2 furnaces and AC units that provide OK coverage for 90% of our 1930s colonial. We have a 2nd floor finished attic/bedroom with a garage and basement directly below. Previously we have used a window AC/heater unit for the 2nd floor room, but it is no longer serviceable. Does anyone have experience using the Mitsubishi Mr. Slim dual-split units? Another option might be to run some new ductwork into this room, but it is not easy due to a cottage roof line and dormers. Also, I am concerned the furnace/AC units can not handle the extra load. They are not currently zoned for upstairs vs. downstairs, but rather the left/right sides of the house. (installed by previous owners)
Re: Mitsubishi Mr. Slim Dual Split Heating and Cooling
Installing a mini-split unit is a good idea in rooms like this, might be more spendy than adding duct work from your other furnace but as you mentioned may not be sized for the extra area. Although years ago many systems were over sized because of heat loss, and if insulation is added that would change,also some were oversized because of poor or no load calculations.
There are many other brands of units also, such as LG, Samsung, and Fujitsu, just to name a few. Hopefully this helps some.