Ductless Mini-Splits – “Busted Myth” or “Magic”?

Ductless Mini-Splits – “Busted Myth” or “Magic”?

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! 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.

busted-myth-or-magic

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 duct work.

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

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 two years1-5 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.

To download the infographic in PDF, please click here.

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4 thoughts on “Ductless Mini-Splits – “Busted Myth” or “Magic”?

  1. Frank,

    You may have misunderstood what I wrote, but to clarify, there is currently no A/C system in the house, and no existing duct work, so we are starting with a clean slate.
    There is a small wood stove in the living area, but it doesn’t put out enough to heat up the bedrooms, and even if it did, there is no circulation between the living area and the bedrooms.

    Thank you for your reply!

    • Sorry. I thought you already had some ductwork. Most of my comments still apply but it depends on how much you want to spend and how much time you are going to spend there and in what season. In any case, keep the wood stove for a while until you get used to your new system. Heat pumps can be pretty energy inefficient at low temperatures.

      I would also get quotes for both ductless and ducted and maybe some combinations of each for different spaces. Sometimes it takes a while to find a contractor who is on the same page with what you want to do.

  2. We have purchased a small single story home in the hills of WV, and we planning to install a ductless system for our heating and cooling needs.
    Only half the house has the option of having traditional ducts installed, and that is the main reason for selecting the ductless system.
    The house is about 1200 sqf total, with one bedroom on the 2nd floor that has big windows on all four walls and a South facing sun room (converted from a porch and is insulated).
    With temperatures in WV ranging from close to 0 degrees in winter to the high 80’s in the summer, and almost endless rainy days in spring and fall, what are the pitfalls and advantages of the ductless systems applies to our situation?
    Will a heat pump be of any use during the cold winter months?
    Does the systems remove enough of the humidity to keep the inside comfortable during the rainy months?

    I have many more questions, but those are more geared towards a local installer.

    Thank you!

    • There are many different opinions about the questions you are raising and most have been discussed and debated on this site in the various posts and comments. I would encourage you to read a few of the opinions and make up your own mind about the risks and tradeoffs. Here are mine.
      I think you should look into retaining the ducted system in the space it is servicing. Look into a gas furnace to go along with either an AC only or an AC heat pump. This would give you the benefits of whole home air flow and filtration along with the utility of the gas furnace for the coldest days and nights when the heat pump has to go on auxiliary resistance heat which is not very efficient. In addition, I would look into either ductless options or a separate new ducted system for the space that has no ducts. With ductless, you get the benefits of zoning and room by room control but the airflow is limited to the areas around the indoor units. Using the ducted central system and some other fans, etc could provide proper mixing of air throughout your home. The humidity issue can be addressed by either ducted or ductless systems but it has to be sized right to achieve the right run time to insure good dehumidification. If you get a variable capacity system in either the ducted or ductless models (or both) it might be a little easier to keep the humidity levels low even in the shoulder seasons of spring and fall.
      The pro mini-split visitors to this site will advise that you should remove the old ductwork and go to all mini-splits due to the cleanliness of the ducts and energy losses associated with air leaks, etc. These are valid concerns and if the ductwork in your home is in bad shape or really dirty you might want to consider abandoning it and going with ductless. However, if it is clean and in good shape though, the benefits of whole/partial home air flow and filtration might be worth considering. We always encourage our visitors to get several quotes from different contractors to make sure they are on the same page with what you are trying to achieve. Good luck with you HVAC project and thanks for visiting our site!

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