Busting Myths on Ductless Mini-Splits: Part II

Revisit the Four Myths that I Proposed were “Busted” Three Years Ago

Revisiting the July, 2013 post, “Busting Four Myths About Ductless Mini-Splits”

When I wrote the “Busting Mini-Split Myths” article in 2013, I did not think it would become the most viewed article on our new website but it has over 365,000 page views and counting! I guess I would attribute the popularity of this topic to how new these systems are and how different they are from conventional, ducted, central HVAC systems, which are found in over 80% of the homes in the U.S. However, in addition to the volume of traffic the number and quality of the posted comments and questions has also been remarkable (over 270 to date).

Although we started out trying to provide a balanced view on this new technology for consideration, I found that I also learned some things as the user feedback continued to come in. This led our team to do some additional consumer research into the U.S. Mini-Split phenomena and this research will now appear in some new articles written by Eric Strausbaugh.  Without going into the details of the study, I thought I would use some of the findings from the study, along with the knowledge contained in the many posts on this site, to revisit the four myths that I proposed were “busted” three years ago.


Myth #1 – The sales of ductless mini-spit systems continue to grow and will dominate the U.S. market.

Status: Still Busted. While mini-splits are growing a little faster than the sales of central systems on a unit basis, the dollars spent on these systems and the number of BTUs of capacity getting installed is still a fraction of that spent on traditional central systems. The reason for this is that the majority of the installed base of homes (over 80%) have pre-existing ductwork. It is simply less expensive to replace a ducted system with another ducted. The air quality and humidity control benefits from central AC are also contributing factors to the staying power of central systems.

Myth #2 – Ductless mini-splits are ideal whole-home HVAC solutions in the U.S.

Status: Still Busted. Our recent research suggests that only a small percentage of people are trying to use mini-splits as a whole-home heating and air conditioning solution; these are mostly in very small homes with no existing ductwork available. What appears to be more popular recently is the “hybrid” approach of keeping the central system for the bulk of the whole home comfort, air flow, air quality and humidity control but also use one or more mini-splits to address areas where consumers want more direct control or where the central, ducted system is not keeping up. Our research articles will go into more detail about this and theories about why this is happening.

Myth #3 – Ductless mini-splits are more energy efficient because there are no air leaks in the ductwork.

Status: Mixed. Based on our research and the comments on the original article, I would say that there are definitely instances where poor or failing ductwork has led to major problems with central systems. No one can argue that the most efficient way to run an air conditioner is to turn it off. If you intend to turn off an entire mini-split zone for long periods, these systems will use less energy than a home that does not have zones that can be shut off. I am giving this a “mixed” rating due to the comments about people also using zones in ducted systems, in addition to comments about energy losses in the long line sets for mini-splits.

However, it has been shown that mini-split installation can also have serious “leaks” as long line sets on the outside of the house can pick up heat in the summer and lose heat in the winter. The result can be significantly higher energy costs than would be expected based upon the rated efficiency of the system.

Myth #4 – Ductless mini-splits provide superior comfort and quality of life.

Status: Mixed. Based on user feedback, I would have to say that for certain situations mini-splits can do a great job and at reasonable costs. However, it would also appear that for whole-home solutions in larger, U.S.-style homes, the hybrid approach of using a base central HVAC system along with some mini-splits for certain areas provides the best overall approach to both comfort and energy efficiency. Combining this hybrid approach with an automated duct zoning system for the main central HVAC would also improve the performance of the overall hybrid approach.

The Bottom Line on Ductless Mini-Splits

If you want to learn more about this topic, check out our first article on the survey of over 350 people who have purchased mini-splits in the past 1-5 years. In the meantime, we would encourage anyone in the market to get a few different quotes for each of the various system types that are available today and consider mixing and matching them to meet your unique needs. It is important to get multiple quotes not only to get the best price, but also to find the right contractor who can recommend the best equipment solutions for your situation, then install and service them well.

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69 thoughts on “Busting Myths on Ductless Mini-Splits: Part II

  1. I found this blog to be very resourceful and well written. If anyone is looking for a great AC company, then you should check out https://www.palmairac.com/. I have used their services repeatedly and I am never disappointed!

  2. My SoCal desert home is a single story appx 1500 sq ft all electric abode. It was built in 1965 with two roof mount ac units ( each ducted to half of the house ) These units also provide the heat.
    For at least three months of the year, tempuratures are between 100-115 daily. The kitchen, living and dining rooms are fairly open to each other. Additionally, the living room and kitchen have walls of glass. The two bedrooms and baths comprise the enclosed spaces.
    My quandary is that both of my ac units are failing now and should be replaced. I can either replace both of my ac’s and associated duct work or install a mini split system.
    I bow to those with more knowledge and experience.
    Any thoughts would be greatly appreciated…

  3. Hi Robert,
    You have a good point, “the technology in mini splits is moving so fast there is a good possibility that in two or three years your model will be discontinued and make it tougher to find matching evaporators.” But I read elsewhere that mini split ductless, with good maintenance, will last between 15 to 20 years. If you look back for the last five to ten years, the technological improvement have been more in the area of energy efficiency. Of the discontinuation of the unit may create system incompatibility.
    Here is the link where I read about adding additional 3rd or 4th indoor unit at a later date. I have copied and pasted a specific part of the statement from it. The story heading is :


    “With Daikin’s Quad-Zone solution, any four rooms can be controlled individually. The 4MXS36RMVJU Quad-Zone is rated for 36,000 BTU Cooling Capacity and must be connected to a minimum of two indoor units. A third or fourth unit does not have to be added right away – one or both can always be added at a later date. The combined BTU ratings of the units chosen can total up to a maximum connected BTU rating of 48,000 BTUs”.

  4. I’ve switched my 1850sf home in Phoenix to mini splits. Because I purchase them in Mexico, they cost less than half what I’d pay online. I have the same amount of capacity the 2 year old 14seer system had, and FAR more comfort. The air handler in the old system was very noisy, and the ducts clearly lost a considerable amount of conditioned air. My electric bill was $81 last month, we had 110 degrees many days and the house was kept at 75. The bill to run the old system in June was about $200, even with 3.8kW of solar. That includes fridge, ice machine, attic fan, heat pump water heater, pool pump 10 hours each night… My experience has been excellent and I will never switch back.

  5. Using a state certified HVAC Installer, I am planning to install a Daikin ductless mini split multizone system in my house of four rooms. The overall goal is to have one indoor air handler in each room all connected to an outside multizone unit with a maximum of four zones capacity. Due to financial reason, the temporary plan is to install only two indoor air handlers with each unit going into one room.
    Over the next two to three years depending on when financing gets better, I will order two matching Daikin brand of additional indoor air handlers to be placed each one into the two remaining rooms. They will be connected to the same outdoor multizone unit that I had installed. I understand each zone operates independently. Is this really technically feasible? If not, why not? I am presently based in Johnstown, PA 15904.
    An HVAC pro visited my house and shared that this approach is not permitted by the manufacturer. The reason provided is that, they system must be installed at once with match or compatible indoor air handlers. He also added that when it’s a right time to add on, he would have install two additional air handlers connected to another second outdoor multi zone unit. I told him that this doe make sense.
    He offered option of install all four indoor air handlers at once and connecting them to the one outdoor unit. The contractor also cited problem with refrigerant flow issue if all the four indoor units are not installed at the same time. I have great respect for the contractor’s option. Its was a surprise. Has anyone ever faced similar issue?
    I am really confused. Look at it this way. If you install four indoor air handlers, one in each room but them you shut off the two indoor air handlers in two unoccupied rooms, you would end up running only two rooms with two air indoor air handlers. That is what the manufacturers told us in their adverts, that saving benefit of using Mult split ductless system.
    How would this different any way if I only install two indoor units then add additional two more units in two rooms for about two to three years later? Cannot really an outdoor Mult zone unit power two indoor air handlers and again, adjust it to power additional two more indoor air handlers when connected to it at a later date?.

    • Not sure about installing just two evaporators it might be ok ask the manufacturer to know for sure. If I were you I would install all single zone units or a dual zone then later another dual zone. My reasoning is if the one compressor on the four zone system goes out you have no a/c period and from what I have noticed is the price of 2 single zone units is about the same as a two zone not sure about four zone cost. Also the technology in mini splits is moving so fast there is a good possibility that in two or three years your model will be discontinued and make it tougher to find matching evaporators.

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