Busting Myths on Ductless Mini-Splits: Part II

Mother and Father laughing with his son and daughter after installation of a ductless mini split system

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

  1. Is that any different than central ac? Anyways, just replace the board! Bout $200 for the outdoor board.

  2. The true downfall from Mini-Splits if you have an AHU (on the wall of course) and a
    power surge eats up the condenser unit. you can’t reuse your indoor AHU you have to
    replace both ends. Sad but true state of affairs. Even same BlueRidge Seer rating heat pump and even first 2 numbers match but born in totally different plants.

  3. I’m here is south florida high temp & humidity no need for heat. 1500 sq ft. 1994 construction poured reinforced cement outside walls shared 12″ wall with roofmate. AC is 2.5T (upgraded from original 2T ) ten years ago. Mold in air handler. Pretty sure either internet fiber or roofers damaged flex duct. House can’t maintain 75 degrees will go up to 79-80 by end of day. Attic is hot as he**. 2 bedroom-2 bath. Hate putting new duct in hot attic. 7 foot ceiling in kitchen slopes up to 12 foot ceiling in great room. Heat load from easterly facing triple sliders and 4 windows south side. Door to garage gets used a lot. Where would you place indoor units? Can email floor plan.

  4. Sure, install a 30k or 36k multi-zone unit with a 2 12k indoor units and add another 12k indoor unit at a later date. Most multi-zone units need a minimum of 2 indoor units connected to operate properly. But no more are required.
    You could install a 5 ton outdoor unit capable of operating 8 indoor units and only install 2, 2 ton units and it would work just fine.

  5. It will be compatible with all of their 2 ton residential units, excluding the wall units. That means the whole house ducted air handler, and the mid static, concealed ducted air handler in the 2 ton size.
    They already have the 9k, 12k, 15k, and 18k hyper heat in stock, ready to ship, with more options in those sizes. I expect the 24k to be out by the end of the year with the 30k and 36k to follow early next year.
    Any more questions, email me at daniel@loweryourheatingbill.com.

  6. Dan, you said that “…next yr they [Mitsubishi] are coming out with a 2 ton hyper heat single zone universal unit for their ducted air handlers and ceiling cassettes”. Will this new model be compatible with every Mitsubishi units?

  7. I am finishing an 800 foot room, well insulated, 2×6 construction, inside an insulated metal building in Austin TX. The 800′ room will have a dividing wall and french doors requiring two separate zone controls. Also a 400′ room on top (a simple second floor bedroom) will be built a year from now so could use a third zone then. Can I add this third zone at a later time when construction is complete, and simply buy a main unit now with the capability to handle three zones and 1240 square feet? Each area would probably need no more than 25′ of line as inside units would all be on the same wall. Thanks

  8. I was totally wrong. Bad information leads to a bad question. It is a basic Mitsu 17 seer unit with no bells and whistles.

    Last year appx same ambient temperature for billing month. When adjusted for number of days in billing cycle, last year with baseboard and a little less comfortable, $500. This year $300.

    My wife quoted me bad information. Or I misunderstood what she said. I just looked it up myself and the real story shows considerable savings with the mini split. Oops egg on my face!

    So sorry.

    • Yes, that sounds more like it! I don’t know which model you have but would be even more savings if you had a GL model. Mitsubishi does not have a residential hyper heat model. If someone wants to buy a Mitsubishi mini split give me a call or text at 717 363 3499. Or email at loweryourheatingbill@gmail.com. i can ship one anywhere in the US. They have a ten yr warranty with the best reliability in the business!

      • Sorry, that was quite a boo boo! I meant to say Mitsubishi does not have a 2 ton SINGLE ZONE hyper heat model. They have it in the 5 smaller sizes of wall units and the floor unit plus all of the multi zone except the 5 ton. Next yr they are coming out with a 2 ton hyper heat single zone universal unit for their ducted air handlers and ceiling cassettes.

  9. Sorry , forgot to mention we live in the NW and the temps are rarely below freezing even at night. Walls are 6 inch with good insulation and all double pane windows if any of that matters

    • Daniel Oberholtzer stated on Jan. 30, 2020 at 6:43 that “Mitsubishi does not have a residential hyper heat model”. I thought Mitsubishi Model#: MZ-FH12NAH and Model#: MZ-FH06NAH are considered as hyper heat models.

      • thanks for pointing out my mistake. Those models r indeed hyper heat models. I meant to say they don’t have a single zone hyper heat model in the 2 ton size.

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