Busting Four Myths About Ductless Mini-Splits

Over the past few years we have all observed the U.S. HVAC industry’s fascination with ductless “mini-split” AC systems. Recent HVAC trade shows have been crowded with OEM’s promoting this “new” way of providing home comfort. National TV ad campaigns along with modern media PR tactics would make us think it is just a matter of time before we all rip out our central AC systems and get with the rest of the world (i.e. Japan, China and Europe) in the way we keep our homes and businesses cool and comfortable. The AC & Heating Connect staff did some research on the facts about ductless systems which might be of interest to contractors and distributors as they plan for the future growth of this segment.

Myth #1 – The sales of ductless mini-spit systems continue to grow and will dominate the U.S. market in a few years. Industry statistics would not support this statement. While the ductless segment has posted impressive growth rates in the U.S. since 2005, the growth rates have been slowing recently and the largest ductless segment (small, single evaporator systems) have not grown at all since 2010. These sales remain stable at about 260,000 units per year, or only about 4% of total unitary AC shipments. Some larger VRF-style commercial systems continue to grow at higher rates, but their numbers in the U.S. remain small at only 28,000 units per year.

Myth #2 – Ductless mini-splits are ideal whole-home HVAC solutions in the U.S. The current economic facts about ductless simply do not support this claim. The installed costs associated with using mini-splits to cool and heat an average 2,000 square foot home with ductless mini-splits would cost almost three times the cost of simply replacing your central AC system with another ducted system. Even in a home where you had to provide new ductwork for the central system, you could still expect to spend about 50% less on a typical central AC system installation versus the more expensive ductless options.

Myth #3 – Ductless mini-splits are more energy efficient because there are no air leaks in the duct work. What people who make this claim fail to mention is that in ducted homes which have poorly installed and leaking air ducts, the conditioned air is probably leaking out of the ductwork but it is going into the conditioned space somewhere and helping to keep the house cool. In those cases the cooling energy is really not lost to the homeowner. While mini-splits don’t have duct losses, they do have other losses. Instead of distributing conditioned air throughout the home, mini-splits distribute refrigerant. In many cases these refrigerant lines are run outside the conditioned space and in these cases there are thermal losses associated with energy transferring from those lines to the space outside the home. A legitimate energy loss occurs when you are heating or cooling your backyard with mini-split refrigerant lines (see photo below). Duct leaks that leak into the conditioned space are not really losses at all unless they escape to an unconditioned space. The other claim made by mini-split advocates is that they provide energy saving due to “zoning” or shutting off energy use in unoccupied rooms. What they fail to mention is there are other modern methods to zone off rooms besides using ductless methods. There are many ways to achieve zoning.

Myth #4 – Ductless mini-splits provide superior comfort and quality of life. The problems with ductless cooling are not well understood by many U.S. consumers since they are relatively new to this region. The typical comfort experience with mini-split systems could provide a real challenge for American consumers who are used to central AC systems with good air flow exchange, filtration and humidity control. Cold and hot spots are also common with ductless systems due to the spacing of the indoor units. In addition, there are concerns about US homeowners’ reaction to the aesthetic and architectural impact of having air conditioning systems hanging on several interior walls and having refrigerant lines running to various rooms on the sides of their homes. Before installing a ductless system with multiple evaporating units it might be good to show your customer some photographs of some of your previous mini-split installations so they have proper expectations.

The Bottom Line

Ductless mini-split systems are ideal for spot cooling situations in homes and businesses where ductwork is either not available or difficult to install. It is important for contractors to have these systems in their portfolio of HVAC solutions for certain situations and learning where and when to recommend them is essential. Knowing the facts associated with these new systems is also essential to avoiding problems when customers are surprised by the many “myths” about this technology.

A typical indoor wall-mounted, evaporating unit – usually one per room are required to minimize hot and cold spots.

A typical U.S. style home is shown here with a retrofit mini-split system. Notice the exterior line sets and condensate drains. Thermal losses could be expected from the vertical, external refrigerant lines and these might cause the system to have trouble keeping up on really hot days. Also, notice that the window-room air conditioners have not yet been removed. A close up photo of the house above, showing the external refrigerant lines and a condensate drain line. Ductless mini-split systems are often used to cool room additions as shown here in the garage area. A large, high rise apartment building is shown, using many mini-split systems – one or more per apartment.A large, urban apartment building is shown, using mini-split systems – one or more per apartment.


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326 thoughts on “Busting Four Myths About Ductless Mini-Splits

  1. We have an 1900 as foot house with lots of open space and a master suite on the second floor. We had a few people, not in the industry, tell us ductless was the future. We had a few contractors come in and all three agreed that given our layout and the available huge attic space (house used to be a ranch, the master suite is only the front half of the house so the back has the original roofline) traditional central would be significantly cheaper for us. We’d need too many of the ductless units, inside and out (even if we had those that could control 4 indoor units) and one guy said the way the tech moves and repairs happen you can have issues with a part replacement on all indoor units or a few, vs just one part on your central unit. For homes where installing central ducts would be difficult or excessively expensive ductless is the way to go. As is true for the many, many cape cod style homes in my area. We decided cooking the whole house with one unit makes most sense even if we don’t use the second floor during the day. The energy loss would be lower than cool air running uostsors all the time and there’s no nice way to block it off. I like that the air in a central system is filtered. Great for allergies or odors if you have pets. The one thing I always envied when in houses wuth central was the nice, cool, bathrooms. You wouldn’t put a ductless in a bathroom usually and not eith window/wall units, which I grew up with. Not having a wall of hot air hit you in the bathroom was always my favorite feature! I think each home needs to be evaluated case by case. Friends of mine who are installing ductless still think I’m wrong. They also argue my taxes will go up only with central. Yeah, because it also increases your value! Ductless is great, don’t get me wrong, but it’s still not central. It’s popular in Asia and Europe because of the age of the buildings. Things here aren’t quite as old.

    • I’ve did a lot of web search comparison between all the models and the Mitsubishi brand is what I’m considering. Keep in mind, it all depends on where you live, how well your house is insulated, do you want it for AC or do you need it for heating as well, warranty, support, cost, and cost of insulation if you are not doing it yourself.

    • We just had a 12,000 btu installed in a bedroom. The room only had one air vent and a sun room off of the bedroom. This unit is a heater as well. It is unbelievably quiet. Additionally, it is big but this type of unit was really our only option. Thus far very happy.

    • Fujitsu systems have the highest efficiency rating and best warranty on the market. Mitsubishi has a similar warranty but is less efficient and a bit more costly due to Thier advertising directly to consumers. But both are top of the line systems.

    • Fujitsu systems have the highest efficiency rating and best warranty on the market. Mitsubishi has a similar warranty but is less efficient and a bit more costly due to Thier advertising directly to consumers. But both are top of the line systems. You will be satisfied with either.

    • Fujitsu systems have the highest efficiency rating and best warranty on the market. Mitsubishi has a similar warranty but is less efficient and a bit more costly due to Thier advertising directly to consumers. But both are top of the line systems. You will be satisfied with either one.

    • We put a Mitsubishi system in our new home and are very happy. We have the lowest heating and cooling costs ever by a large margin. It is just two of us and we have a combination of three Mitsubishi units, two on main floor and one in master suite. The individual bedrooms and baths have their own thermostat controlled wall heaters which are rarely used. We also have wall heaters in each room of an ADU in the basement. We therefore only heat the areas we use the most and don’t waste energy heating unused spaces. Our home is 3,850 sq ft including at 750 sq ft ADU (rental).

  2. I have a klimaire 36,000 btu 16 seer mini split heat pump tri zone system that only has two indoor air handlers a 9000 and a 12000 I want to add a third 9000 indoor air handler… this system is only three years I am told by klimaire that I have to replace the whole system because they don’t sale just the indoor units is there any other indoor unit that I can use with this system

    • Hi Sandy – It is pretty difficult to add an indoor evap to an existing multi-split as they are designed for a certain capacity and number of indoor units. You might be better off just installing a separate single split. You can ask a few contractors but I would look into that option for sure. Hope this helps. Thanks for visiting our site.

      • Unfortunately you cannot just add to the system if the system is only designed for two zones! You would have to replace the whole system or just install a single zone for the additional space!

        • She clearly wrote that she has a three zone 36,000 btu system currently running two zones, one 9,000 and one 12,000. What’s happening to reading comprehension these days.

        • She clearly wrote she has a three zone, 36,000 BTU system currently running only two zones drawing 21,000 BTU total. What’s happening to reading comprehension these days?

  3. The article was written by someone who makes statements which are FALSE.

    Duct work is run out side of the condition space in LOTS OF AREAS of the country.

    there is really no comparison for mini splits vs a whole house ac system. If your whole house goes out your not going to convert to mini. Throwing numbers about is a fools errand. Each install must be evaluated separately.

    Seriously, hot and cold spots exist in almost EVERY installation. Not just mini splits

    There are ways of cleaning up the installation of the refrigerant lines. I have sheet metal boxes made and paint to the color of the house.

    • I couldn’t agree more! Each install is different and I’ve seen many attics that have central ac in them, not only is it not a conditioned space but the ac creates more heat in an already hot space. I have swapped out my old single pipe oil steam boiler and now heat my whole house with mini splits and I went from spending almost $3000 a year in oil to about $700 in electricity per winter

  4. There a racket going on against ductless mini-splits. In Asia and many parts of the world, this is the de-facto system, and it is relatively easy to install, and efficient. How can it costs $2000 and more to install a $1000 10kBTU unit, that only takes 3 hours or less to install?! I was even told its $8k to install one. So the AC guy just say it is better to install the clumsy central unit instead …. to cool 1 room / garage.

  5. Hi my is Antonio Almodovar i just started looking at ductless air coniditioners i am looking to my hold house at a good price i have about 18,ooo. sq ft.

  6. Let’s mention ducted hi pressure systems.
    Those seemed to never have had their spotlight time !??????
    I did my own home and I have no visible refrigerant lines or
    huge boxy interior units. Just flush and tiny 2″ holes in my ceiling
    and a soft wherrrr of air. No hot or cold spots.
    My unit even has soft-start or slow cycle of air when not cooling
    to keep things even temp. Also works well if you have a fireplace
    to get the heat around the whole house evenly if desired.
    Zero maintenance in 15 years other than 1 filter periodically.
    No ducts to clean ever because nothing can remain in 50 mph airspeed. No duct leaks… it’s all 1 solid and insulated tube from the unit to the duct and all ducting is wrapped in fiberglass and
    reflective Mylar. I have a 3 floor home and it’s not ideal for this setup but I was able to do it fairly easily.. I am handy though 😉
    UNICO system was my choice… there are others.
    I would think most people researching splits already have heat…
    therefore, like me, I needed just art conditioning.
    I elected to go with UNICO but there are others..
    I carried the cube units ( evap, blower, intake.. etc) to my attic myself and just clicked them together with this suitcase style latches… ran my line set through one of the same accesses as I ran some cooling tubes. Called my air conditioner friend and he
    finished the gas work for $180.00
    I would do it again! Not one regret or unsightly boxes or pipes.

    • Where were you able to purchase the UNICO components from to put in yourself? I’m gutting down to the studs a 2000sqft old home comprised of two additions that makes putting in traditional duct work difficult. I’m going with hydronic heating, but air conditioning is a challenge and at least with the UNICO I can even put in a hydronic heat exchange.

      • Any semi gutted place is a dream for a UNICO.
        Being into heavy handyman, it’s easy to open accounts all over
        at all wholesale places under just a business name and get almost anything at wholesale. I don’t abuse it or make myself a hack-. I just purchase it and do what I can in a professional manor and leave the gas work to the pros… if you can find one that doesn’t call you a scab while he’s finishing your work .
        Too funny…. there techs that will take interest in finishing and overseeing your install and not be pissed that they missed an
        opportunity to rake you…. there are plenty of those unfortunately.

  7. I love my mini split unit. I live in less thang a 1000sq home.
    My problem: my insurance hasdropped me because they don’t consider it a central heating unit. No i am on the look out for insurance that will accept my ductless unit. Any ideas who i can go to?

    • I own Access Insurance in San Antonio. Your current agent does not understand mini splits. The only requirement should be that the heat source is thermostatically controlled. I just installed 3 in my 2500 sq foot house. Let them know it is a mini split heat pump system.

  8. Hilarious… very little knowledge in any of these comments. In Mexico, you can buy Mini-Splits off the shelf. I love how people who are not in the industry say everything is so easy. If it was everyone would do it. They are no different than window units and 10x more complicated to work on and repair. If you have an issue with your standard duct system it’s because you got a low bid, unlicensed moron to install it and didn’t bother to think to keep up maintenance on it just like you will with your mini-crap unit. Don’t bother replying because I have had my larf and am moving on.

    • Good points. I would also suggest that people reading this should check the US regulations for unitary systems including ductless mini-splits, regarding both refrigerant (now R-410A) and the minimum allowable efficiency standards (now 13-14 SEER – depending on the DOE region). There are differences between regs in the US and Mexico. I am not saying these regulations are right or justified. Just sayin the US has different standards and they are enforced – unlike many of the “developing countries” who were not held to the same “standards”. Do your research and talk to a few good contractors. What can that hurt? You might save some $ and avoid a costly mistake. I know where AC Genius is coming from. There are a lot of posts about non-US applications on this site. Most of the visitors to this site are US consumers. We might get into writing about international applications at some point but we are still dealing with US issues at this point. Thanks for visiting and commenting. I am just trying to clarify some of your points for our readers.

  9. We put in ductless in our 1980s New Hampshire home 5 years ago and love it. But obviously we don’t have the really hot conditions of the southern states. Now we have plans to build a rustic cabin in Texas. We would like to use ductless again, but the climate is so different. Would we be foolish to do so?

    • Hi Naomi – since you already have experience with ductless systems you might just want to review some of the pros and cons described on this and other article threads on the site before making your decision. Reasons for going with ductless include: zoning for control and energy savings, ease of retrofitting into a home without ductwork and possibly lowering your costs to install and operate. Reasons for not using ductless include concerns about air-flow and filtration throughout the whole home, dehumidification on humid days and heat pump heating on very cold days and nights. One thing you might consider is a hybrid approach that features a basic, small central system (heating and cooling or heat pump) with several mini-splits in the areas you want to zone off or control separately.

      Here is a link to a homeowner survey which might provide other insights.


  10. I posted this “ductless myths” article over three years ago. Since then, over 400,000 pages have been viewed by people wanting to learn more about this topic along with wanting to see the various opinions about ductless mini-splits shown in the almost 300 responses that have been posted since then. Some of these posts are very pro-ductless and some are less than favorable toward the technology. I would encourage people who are interested in this topic to read comments from both sides of this debate and then form their own opinion about whether going ductless is right for their situation. And we always recommend that you talk to a few different contractors about different system types before deciding which to use.

    I posted a follow up article a few months ago which attempts to summarize conclusions we have drawn from all the various responses to the original article along with a summary of the opinions shared in the various posts. This could help provide some additional insight into this topic and an overview of the 300 posts to the original article.


    We also have posted the objective results of a 2016 homeowner survey of over 700 US consumers who recently purchased ductless systems, why they decided to use ductless technology in their home and what they liked or disliked about them. This should help you understand if your reasons for choosing a ductless system are similar to those who are already using this technology.


    As I have watched this debate play out in the US HVAC marketplace, I continue to believe that ductless mini-split technology makes a lot of sense for many applications – and some more than others. Ductless has proven to be an ideal solution for many applications but like most things in life there are no absolutes and there are often trade-offs which should be considered, studied and understood before investing. On this site, we are attempting to provide a forum for people to hear both sides of these and other debates about HVAC technology in a fair and open manner. I hope our visitors find that some of this information is useful.

    • I like your review and subsequent comments. I’m personally looking at a mini-split system right now for cooling and supplemental heating (I’m using whole-house underfloor heating) in my new house build. The design doesn’t really allow for ductwork and the relatively small size (~1000 sq ft) makes me think that ductless is the way to go.

      • H Jerry,

        That should work. Just make sure you get a few different quotes and make sure they get the capacity right for your space and the cooling season load. There are some articles and posts about the trade-offs between single splits and multi-split (multiple indoor unit) ductless systems so you might want to research those before talking to the contractors.

  11. I live in Washington state and got multiple quotes for ductless heat pump and installing duct work and a heat pump and the ductless all came in about $3,000 under the price to add duct work and heat pump. Also all the energy companies give rebates for going completely ductless or natural gas because they say they are more energy efficient. There is no rebate for a normal duct heat pump even though we are upgrading from baseboard heat. I also have people I know that have been in the hvac industry and told me that ductless is the way to go. I read this article first when I first was researching about the ductless systems and ductless is the way I’m going. A lot of this article is not accurate. Just make sure you get your ductless system sized for your house and you will be fine.

  12. What a farce of an article. Clearly worded to steer people away from purchasing these units. The central AC is a beast of inefficiency. Some rooms hot, some cold. Also, the AC technicians try to sell you $7k units everytime something goes wrong with them. Instead of replacing a $150 part you have to hear the $7k sales pitch. It’s BS! I’m ripping my central AC out so it’s for sale if anyone wants it.

  13. I’m an HVAC contractor in the Caribbean. A couple of things were not mentioned here in favor of Ductless. It takes a lot of energy to spin a PSC blower motor to push and pull Air through ducts. I routinely see 40 watts per ton or less on a Ductless for Air distribution using variable speed D.C. motors. Ducted systems will be 3-4 times that. Also, most modern Ductless systems are inverter type variable speed compressor. The system can idle along at 1/3 capacity all day at a super high EER, distributing cool, dehumidified air increasing comfort and saving energy. I lived in a home for a year with 4 Ductless inverter systems. The insulation was non existent but The comfort level was great and our bills were low. Now we live in a house with Ducted splits, 18 SEER, and it’s far from comfortable. Bills are ridiculous. The system comes on and we freeze. It cycles off and we sweat. All day long. On, off, on, off…there’s no comparison. Ductless is here to stay and central Air will become an antique in the next few decades. It’s 80 year old technology and we Americans are the only ones still using it.

    • Where in the carribean are you? I’m looking for an English speaking company that would replace be able to replace my current (leaky) central air conditioner with a multi-split. I’m in Bavaro, Dominican Republic. Right now I have to refill with refrigerant every 6 weeks. which is not cost effective.

  14. 3000sq ft running Gree Crown in Northern MI, running a 36,000,30,000,24,000 7 head units. Love it!! Problems include covering outdoor units to protect from weather. Benefits, electric bills from radiant heat to mini’s 500.00 bills to 200.00 for electric and a warmer house. If my whole system dies in 4 years and has to be replaced, if will have paid for itself. Cost was 10,000 I put it in.

  15. Just thought I’d shed some light on your cost comparison, with central systems bring 50% cheaper. Well I’m in the final phases of a 3,400 sqft custom timber frame build, I assume you got your figures from well…..Not an installer that does this everyday. Cheapest quote I got for central ac here in NC was $22,000. Mitsubishi dustless came in at $16,000. Funny enough the ductless is 20 SEER, and the central system only 15 SEER. Have you ever ran an efficiency calculator on a 5 ton system with with two separate systems 5 SEER apart. Ignorance is bliss.

    Readers, please do your own research on the matter before taking the advice of one guy, one article. Not everything on the internet is truth, talk to a certified professional with a long track record. Such bad information.

    • Thanks for you comments Zach. The cost estimates I used for that article were based on national averages across various regions with no allowance for non-standard construction or other installation challenges. However, as we note many times on this site and in this article, prices can vary from job to job, location to location and from contractor to contractor so we always encourage getting multiple quote until people find a contractor who can install the equipment to meet their needs – and this includes ductless. There are situations and comments posted on this article and others where I have supported the use of ductless systems. I agree with you that for many applications ductless systems will work fine and can provide both operating and first cost advantages. Thanks for pointing this out.

  16. This article is extremely biased. We love our ductless mini split system and it heats most of our house up with just 1 unit. Eventually we want to add one in my office and one in the bedroom for those winter months when it gets a little chilly in San Diego.

  17. Mr. Landwehr,
    When you include one out of four, (that’s 25 percent), unclear or actually false statement in your information it leaves it all ‘suspect’ at best.
    I suggest you consider rewriting or removing you “Myth #3” from your above story. I have NEVER seen nor spoken to anyone, who has seen ducts IN climate controlled space except in warehouse type stores and THAT is obviously Not who you are writing to regarding split (mini) system A/C units. I came to this site looking for ratings to share with potential users, but when I read #3, I knew, I couldn’t rely on the remaining portions. You will probably delete this but at least present your position with accuracy for those who may view it in the future.

    • Hi Dan. Thanks for your comments and opinions. We have had a lot of debate about those issues you raised in your post so thanks for sharing. I guess I was referring to ducts that were on interior wall spaces and not on external walls like the linesets on multi-splits. I hope that helps to clarify the point I was making. In any case thanks for using our site. We do not generally delete posts unless they are violating profanity or endorsement policies so we will leave it up. Maybe others will comment!

  18. Í don’t agree with everything said about ductless ,I own an AC company for 25 years and we have gone from installing central systems (unitary) to 80% ductless as part of our business.
    Ductless technology is here to stay,less maintenance ,more reliable,more efficient,no energy loss
    The comment made about central system leaking air in a condition space is very rare,must duct work are up in the attic or basement therefore the air is losst because is not a condition space ,refrigerant lines outside the wall,must central systems have the lines outside the wall unless is a new construction job.

  19. We live in a 2,000 square foot home with 1/2 main level and 1/2 basement. Our basement stays roughly 68 year round. Our summers are hot and dry (ave 80-100 F with low RH) but cool to 40-60 F nightly). We have had a roof mount evaporative cooler for the past several years. It leaked, we had to replace the roof, and decided to install our AC differently or use a different technology. We LOVED our evap cooler. 1/2 of the main floor is a kitchen, living room, dining room combo. The other half is 2 beds and a bathroom – one bedroom is rarely used.

    We have forced air central heating so we can get a ducted AC system. The mini split seems attractive because we don’t need to cool our basement. Between these two technologies, it seems like a good deal to only pay to cool 1/2 of your home. We also wonder if anyone in the US is doing ducted evaporative systems where we could mount the evap cooler on the side of our home.

    • To EM:
      re “We also wonder if anyone in the US is doing ducted evaporative systems” — Yes.
      I lived in New Mexico for several years and roof mounted, ducted evaporative systems was the most common type of system used. Some installs were ground mount beside the house but they were unusual due to the houses (typically slab foundation) not having basements. The ductwork was in the attic and would be switched between the furnace and the cooler.

  20. Hi. Was wondering if you could give me a suggestion. I’m making a room in our attic (in upstate NY). We have a normal stairway that goes to the attic with a door on the bottom of the staircase. If I install a ductless mini split right above the staircase, would that be ok? Or will the cavity of the staircase “eat up” all the cold air and the room will remain hot?

    Thanks so much for your help.

    • Hi Aron – You could experience problems with that location for a mini-split in that the cool, conditioned air coming right off the coil may flow down the staircase into the lower floor (cold air flows downward). Similarly, if it was in heating mode then the warm air would tend to rise and stay in the upstairs space. Mini-split systems are designed to condition a space (one room or two) and the air flow does not reach much beyond that. You might want to try moving it away from the stairway or add some other means for air movement (e.g. a ceiling fan) to compensate. You can ask a few contractors about it to make sure. Without being on site it is difficult to consider all the other factors that might be affecting your comfort in this area.

  21. The ductless Mini Split is very easy to install, and in China, the installation is free when you purchase the system. And it only take two technicians less than two hours to complete the job. This is definitely a DIY job and I don’t believe any of these guys got A/C certification on this type of installation. It’a just about drill holes, and connect pipes. They got training at the factory like Haier or Gree. If the installation labor cost will be as high as in the US, I think most Chinese will do the installation themselves. http://item.gome.com.cn/9134265716-1123200734.html?cmpid=ad_it168_cpk_3_o_2_o_20141231_o_o_o
    This Gree model cost $500 with installation included. I guess here HVAC guys just gouging the consumer for such a low-skilled job.

    • Agree. Obviously the AC industry here is pushing for big, complicated central systems that clearly need pros and more importantly, license, to do the work, and have them gouge the consumers. It is ridiculous in 2017, the US is still installing giant noisy window units as the alternative, when split units are quiet, efficient.

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