Four Myths About Ductless Mini-Splits

Understanding the Pros & Cons of Ductless Mini-Split AC Systems

Over the past few years we have all observed the U.S. HVAC industry’s fascination with ductless “mini-split” air conditioning systems in the U.S. Recent HVAC trade shows have been crowded with OEM’s promoting this “new” way of providing home comfort. National advertising and media/public relations tactics would make us think it is just a matter of time before we all say goodbye to 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 article below was written in 2013. We have updated information for homeowners busting myths about ductless mini split systems, outlining what to consider when choosing a new HVAC system, as well as recommendations on when a ductless system might be right for your space.

The AC & Heating Connect staff has also conducted research on ductless systems and uncovered some facts that might be of interest to contractors and distributors as the industry plans 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 ductwork.

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.

*Discover the updated status of this myth here.

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 airflow 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.

*Discover the updated status of this myth here.

The Bottom Line on Ductless Mini-Split Systems

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.

The myths in this article have been reevaluated. You can find the updated article here.

What has your experience been with ductless mini-splits? Leave us a comment below!

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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529 thoughts on “Four Myths About Ductless Mini-Splits

  1. Noveto, not true. I have one unit upstairs and one unit downstars. I have 3500 ft sq home. Dont forget basic thermodynamics, heat is attracted to cold. I have lived in a house with central. I have lived in a house with two mini splits,only 18,000 BTUs each. Standing next to mine I cant even hear it running! I was visiting a friend three weeks ago and had forgotten that noise every time a central system comes on. It woke me up four times. And show me a central system you can run on three solar panels. It doesnt exist. Why? Because the current draw on a mini split is so small in comparison. My 18,000 BTU mini splits use less current than just the motor to circulate the air on a central system. Each HP equals over 700 watts. That doesnt count the compressor and other functions of a central unit. My entire mini split uses around 700 watts, total. As far as the 50 million units now in use in Asia, they are not just in homes they are also in industrial buildings and office buildings. I have a good friend in Tokyo and I know the facts. Once again people, dont be fooled by HVAC dealers who troll these sites and attempt to discourage people from buying mini splits because they are so inexpensive they cant make huge profits on them. I think it is a bit late for that. Closing the door is useless. The horse is already out of the barn. People told me I was crazy when I built and used my first solar energy system in 1970!

  2. Thank you for the article. I too am about to replace my old furnace and air conditioning unit with a vastly more efficient ductless system. I am ecstatic about the idea! My boyfriend sold whole house systems and now even he believes that the ductless mini splits will continue to phase out the old systems. It’s obvious to see why. When I moved into my 1250 square foot home in the North Georgia mountains, I spent several days on my knees vacuuming out the considerable crap from my floor vents. I used a sponge and soapy water and rinsed and rinsed, then took metal tape and taped every crack I could reach. Up here, heat is more of a concern than air conditioning. I got quotes for replacing my old unit with a much more efficient new outdoor unit but after doing the math, decided to go with the mini splits. For so many reasons! 1. The cleanliness of the air. 2. The humidity control. 3. The extra pantry that I will have once my nasty old contraption is gone. 4. The efficiency! 5. Did I say the efficiency?!

    Hands down, the US is the slowest moving country on the planet when it comes to efficiency. BUT, I would not trade my water guzzling, perfectly operating old Maytag washer and it’s twin dryer for anything. Now that I have whole house, spring water well fed propane tankless endless hot water to shower and clean with, the next logical step is ductless mini splits. I look forward to watching my electric bill drop by enough to pay for the improvement in a year or two. But thank you for the information. ~ Susan in Cleveland Georgia.

    • Prove to us that mini splits are more efficient than modern hvac central units. Energy efficiency isn’t that rating you see on a sticker. Efficiency takes into account the entire system especially its size (volume) and level of comfort. Having freaking cold spots in your house is not efficient heating and cooling. Energy efficiency is related to the area being heated and cooled. Large houses require multiple mini splits. Shutting off individual units and not conditioning the air in that room does not improve energy efficiency or house comfort. It may lower your energy bill, but that is NOT energy efficiency.

      You seem to be ignorant of the fact that most Europeans, Japanese, Chinese etc. live in tiny spaces. Houses larger than about 1,500 sq feet are better served by more efficient central HVAC systems. Plus your large houses will look like crap with those junky-looking compressors all over the place. And no, I am not a dealer. I own a single house with BOTH systems-one for the original house and mini splits for the addition and basement. And HVAC dealers all sell and install both systems so there is no conspiracy by “big” HVAC to stop mini splits. you should rely on their expertise in choosing a system.

      • Proof for me was my electric bill. It barely moved conditioning my entire home vs a couple window units. And… home is larger than the size you list. While many installers can do both, like anything, some are better than others. Some take into consideration room size, room location AND know how to hide those ‘clunky, units where feasible. Not to mention, inside I didn’t have to worry about furniture placement and blocking a vent. You also mention turning a unit off in a room isnt efficiency? Why exactly not? I close bedroom doors to rooms I don’t use or need conditioned……..that’s efficiency. Having the ability to cool a room more than another because it gets more afternoon sun than another room is efficiency. So you have experience of both but sounds like maybe your installation may have sucked. I’m going on two years in my 2700 sq foot home and so far have no complaints. In fact…..where I needed extra warmth during the winter I simply used the heating feature. Happy with mine, the brand and my installation.

        • Window units average SEER is around a 10 rating. Mini Splits go from about 16.5 to 22 SEER. Not having any reduction in your utility bill is very odd, if not almost impossible.

          • If you buy a car like my diesel which is rated at 45-50 mpg and you compare that with a car rated at 20-25 mpg, there is no difference in those ratings, generally, and the ratings of a mini split, up to 22 SEER compared to one that is rated at 11 SEER. (My diesel actually got 53 MPG!)

        • Great point! I am totally convinced that DUCTLESS is the new way to smartly condition my 1250 square foot home. And yes, you are so correct about the vents preventing furniture placement! I currently have to work around the floor vent in my master bedroom just to do a work out on the floor. It’s annoying to put it mildly. I already have my contractors scheduled to do the mini splits AND lay my gorgeous barn wood laminate flooring in every spot that I currently have a vent. That’s another reason to change my system. Kudos all around!!

          • One more thing. You’d have to be a dumbass to not install a simple mini split system correctly. There are YouTube videos and DIY mini splits online for those of us who have the experience and know how to do it. If not for my contractors, I’d be doing it with a friend. I worked as a carpenter for two years and this has to be one of the easiest things I’ve ever seen. Anyone who has exterior leaks just didn’t do it right.

            • I know several people who installed their own with no HVAC experience whatsoever. Having electricity run to the units if it is not already conveniently located is left to a professional.

              • Average installation time is 2 hours. If you are going in new construction with a central system the installation is at least two days which includes the ductwork. Multiply 16 hours, two installers times the average hourly rate charged by the dealer at $80.00 per hour and you just bought yourself a mini split for just labor charges. Then add to that the cost of the central unit and you just spent enough for two mini splits plus the cost of a European vacation. If you go on the web pages of the major mfrs of central systems you will not find out much. Try Trane for example. And try Carrier. Online dealers for mini splits tell you everything you want to know in less than five minutes. Also see the SEER ratings for those expensive ducted systems. Sixteen? And that one is really expensive! As as footnote, in my situation, try running a central system on three 250 watt solar panels. The panels cost about .75 per watt. Hey, it aint gonna happen!

  3. Wendy Petrak on April 3rd at 12am
    I have no knowledge of these mini splits. I have a 3 level 1350 sq. ft. condo that is all electric with a flat roof on the upper level where the bedrooms are. No central air or heat. Could these make us more comfortable in summer and be more cost efficient then portable or window air conditioning? The bottom level is garage, 2nd level is living\ kitchen and the bedrooms are third level. So very hot in summer and cold in winter.

    • Yes go with mini splits and use it for heating as well. My house was electric baseboard heat and I went from $1000 a month in the winter to $700 total for the entire winter to heat the house.

  4. I put in a split it worked 5 months and it’s not worked since 3 different people came out to fix it all I got were bills most companies don’t know how to work on them it’s been a nightmare and a waste of money

    • Eileen, all major brands carry a warranty. I dont know what kind of unit you purchased but read your warranty. If you bought a cheap knockoff then be a more prudent shopper next time,

  5. It would be very interesting to know if the author of this article has ever used a mini split? I dont mean turned one off and on bu really used one.I did read about heart surgery once but that doesnt qualify me as a heart surgeon.

  6. We are considering spit unit for our storage container home. My question would be, would this be better than regular ac unit? Not really room for ductwork.

  7. Hello There,
    I was researching on how much energy Split system uses and came across this site which is having great discussion about mini split systems.
    We are thinking about replacing our Oil based heating with mini split this year. Oil will be backup and for hot water. We live in around Boston, MA. Last year (Jan-2018), we installed Solar panel. Our yearly need was 7500Kwh for 2500Sqft house but installed 10500Kwh system to support future additions including mini-split systems. This winter we made aggressive use of two space heaters (1500 watts capacity each, used average 12hr per day, from Oct-2018 to Mar-2019) to save on our oil bill. Our Net-metering initially worked in summer months. But by end of Feb-Mar-2019, we started getting bill even though we had produced 13000kwh till date (Jan-2018 to Mar-2019). Electricity company is saying it is due to lot of heater usage. Rest all of our equipment are the same compared to our last year usage.
    Now I am wondering if I install 3 split units ( Fujitsu-Halcyon 18K BTU) with 7 heads, what will happen to my electricity bill? Even in Summer months where Solar production is generally higher, I will be using Split system for AC.
    Can someone help me analyzing how many units of electricity such system typically uses (not the $ amount). Based on my space heater experiment this winter, I need to calculate if is worth spending $$ on split system.
    Thank you,

    • What is the fuel for your space heaters? If you have natural gas or can get a propane tank, that is your best route for space heaters. You just use them for back up or when your power is out? With the gas space heaters you always have a ready supply of gas and it is cheaper by far than if you are using electric. Those gas ‘wall heaters’ are less than $200.00 online. BE SURE YOU GET ON WITH A THERMOSTAT, not high, medium and low so they will cycle on and off then the temp is satisfied. My LG mini splits have worked just fine in the coldest weather here in the Atlanta area. About nine degrees and according to the mfr will work down to zero! I see no reason yo0u wouldnt be please with the mini splits as long as you have backup heat when the power is out. I know you mention units with multiple evaporators/inside units, but the price goes way up when you do that. I seriously prefer one condensor/outside unit to one inside unit. Strategically placed in 2500 ft sq you can do a lot with even two 18,000 BTU units. I have over 3000 fr sq almost equally divided upstairs and downstairs. They will run you out of the house winter or summer if you want that. My house is an open plan and super insulated. Maybe this helps. Oh and you can zone by not using both all the time if there are areas you arent in often. They will bring the temps to normal pretty quickly if you have an area closed off and want to open up the doors. You may also consider louvered doors in the bathroom especially for continued circulation and if you turn on the vent fan in the bathroom it will stabilize quickly. People have tended to forget that rule of thermodynamics that ‘heat is attracted to cold’. An asset in summer or winter that saves you the expense of a central system which is not generally zoned and uses as much current to run the blower as a mini split uses for its entire operation. Glad to hear you were smart enough to get some solar panels. Best investment you will ever make especially compared to having that money in a savings account!

  8. Hiya Barbara,
    I just want to say I am not in the business of making money on mini splits. My initial interest was that I could operate them using a few solar photostatic panels. The current draw is so low compared to conventional whole house systems. And on the grid, the savings are at least half. Plus the filters are reusable and can be vacuumed in place, five minutes. No more buying filters!
    Now on to your question: I would use two small units depending on your climate. You could do only one unit, but I suggest two small units strategically placed. Maybe a 12,000 in a smaller area and a 18,000 in a larger area. There will be times when your entire house can be handled with the larger unit alone. Unlike the central units, these mini splits throttle themselves up or down depending on the demand saving lots of money and you dont have to do the entire house if you want to shut off a room or two. You can buy units online, be sure you get free shipping. Total for the two, brand name like LG should cost around $2000.00. Shop around! That compared to a central unit at around $6000.00. And if you have allergies in the family you can grow mold and bacteria in the duct work of a central system, yuk. Call several HVAC dealers and ask for their hourly rate for house calls. Should be $65-85. Takes about two hours to install each. You probably have an excess of 220VAC to operate both due the overkill required for the heat strips already in the house. Any more questions let me know 🙂

      • You are welcome. I dont care what the naysayers put out there mine are flawless and have been a welcome addition for nearly 15 years now. They biggest naysayers are the HVAC dealers themselves because they cant make bit money on them. They need to wake up and get on the train or be left behind.

  9. I am considering purchasing a 3 br home, 1 bath, LR, Kitchen. Total 1200 sq. ft.
    Home does not have central ac or heat. Baseboard electric heat and window units. If I considered the mini-split units, how many would I most likely need for this size of house?
    Would I need multiple compressors and blower fans?

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