The “Mini Split” Heat Pump/Air Conditioner System

The “Mini Split” Heat Pump/Air Conditioner System

As I reflect back on 2015 (not 2016) I would label it the year of the “Ductless Mini Split Heat Pump / Air Conditioner” which is sometimes referred to as a “Ductless System”.  It consists of one Quiet High Efficiency Outdoor Compressor Unit and one or more Super Quiet Indoor Air Handler Units.  The indoor unit(s) and outdoor unit are connected together with two insulated copper tubes, an electrical wire and a thermostat wire which are all neatly hidden on the outside of the house with a “Duct Hide” cover (three colors available).  The desired Room Temperature is set for each indoor unit using a remote control – so – relative to temperature, you can control each indoor air handler separately.  Nice!!  Hyper Heat Outdoor Units are offered that will hold the same btu/hr output down to single digit outside temperatures.  Mitsubishi Systems now offer an indoor Air Handler with electric backup that can be ducted into rooms like a conventional Warm Air Furnace or Heat Pump System.

We are fortunate that Mini Splits HP/AC are being widely accepted today.  It wasn’t that long ago that few wanted to consider them for heating and cooling their Home.  They “didn’t like the indoor unit hanging on the wall” was the usual reply when I mentioned them to a perspective customer.  These highly efficient units have been popular in Europe for many years primarily because most Homes are heated with a hot water system – so – installing a traditional central HP/AC system with duct work is difficult and expensive.  In addition, if you lived downtown on one of the upper floors of an apartment building heated with hot water, a traditional central system wouldn’t be feasible.

The Mini Split Systems derives its high efficiency and the ability to service multiple zones from the Outdoor Variable Speed Compressor.  Simply stated, the more Indoor Air Handlers that are running the faster the Outdoor Compressor runs.  This Variable Speed Technology is now being used by Trane and Carrier on select high end models for their central ducted systems and I’m certain you will see this technology used more and more in the future.

Traditional Ducted Systems are ideal for a Ranch House with a full basement.  The duct work can easily be hidden above a drop ceiling and there is a supply register in every room.  One carefully located thermostat controls the temperature of the single floor system.  Because it’s a central system an electronic filter or media filter can be added as can central humidification for those dry winter days.  And You only have one filter to maintain which is recommended twice a year.  You can also use a high efficiency gas furnace backup in lieu of electric.  A Gas backup unit is not available with a Mini Split.  For a 1-1/2 or 2 story Home the ducted system installation becomes more complex and the Ductless System should be considered.

As a general rule in the simplest system an indoor wall hung air handler is located in the Family Room and Master Bedroom.  A third unit can be added in a second bedroom.

We in the HVAC Industry are happy to see the Mini Split come of age.  It gives another highly efficient tool to use in our quest to provide a comfortable Home throughout.  So – what is the best solution to Heat and Cool Your Home or Business?  It may be a Mini Split Ductless Heat Pump System.


Curt Bierly is president of the bierly group incorporated of which Stanley C. Bierly is a division.  He is chair of the Penn College HVAC Advisory Board.  You can contact him at 814-349-3000 or