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” 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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426 thoughts on “Busting Four Myths About Ductless Mini-Splits

  1. I can get behind some of the arguments made, but you lost me when you talked about cooling your backyard with the refrigerant line. The lines are typically so short that heat loss would be negligible when compared to the loss that would occur when you have poorly sealed ducts losing air into my “unconditioned” attic space. In reality both system have their value. A whole house solution is the most economical way to cool a house from a startup perspective. I worked in the commercial HVAC industry for many years and we still used packaged HVAC system when cost was a concern. They are definitely significantly less expensive than purchasing some of the new variable refrigerant models out there. However all of that being said, a ductless system is a very nice solution for the added space or the one room that just never gets cool. I would not be very excited about a unit in every space of my house but for specific space in the home they work great.

  2. “..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.”

    HA! Really? You call the 100+ degree attic a “conditioned” space? Not in any house I’ve even been in. I worked for many years in the HVAC industry and I’me here to tell you that conventional ducted central air in most residential applications is a hole in the ground where you throw money, and I made a good living off that money. Granted, ductless mini splits are comparatively a new technology that sometimes has a bug here or there, but the main reason conventional ducted companies don’t like them is because they are EASY for a do-it-yourselfer to install, and usually come with easy to follow installation instructions with good tech support. This cuts the big HVAC companies off of the money trough. And, unlike a big whole-house A/C system, you can have 4 or or more well-placed mini-splits heating and cooling the house. And, if one of them goes down, you can still partially heat or cool the house. Ever sit in a house in Texas with no working A/C during the heat of the summer waiting on the repairman to finally show up looking for you to hand him that blank check so he can “fix” your A/C? I’ll never do it again!

    • Hi Steve,
      I’m intrigued by your comment that the ductless systems cut the HVAC guys out.

      I’m looking at the Mitsubishi Hyper Heat systems up here in Boston for apartments and getting prices from HVAC companies between 7K – 11K per system installed.

      Now, I’ve outgrown the do-it-yourself phase (mainly because I’ve realized I’m not very good at ‘it’ -whatever it is). But I will keep searching for installers, if out of trade installers are an option.

      BTW my beef is that the ‘good money’ up here means $2,500 per man a day. And, installation does seem quite straightforward…

  3. No issues. They are very efficient and they cool and heat (they are also heat pumps) better than the whole house system. We live in Colorado and now only run the furnace as a backup on very cold days in the winter. At night the furnace hardly runs because we close the vents to the bedrooms as the heat pump puts out enough heat. the 9000 btu units only use 6 to 10 amps while running.
    Also the furnace works a lot better on the real cold nights because there is no a-coil which reduced the efficiency of the furnaces air flow.
    In the summer we don’t miss the noisy compressor or the noisy air flow from the ductwork.

  4. Due to asthma I can’t tolerate old fashioned swamp coolers, hate noisy heat exchangers, & ducted AC units aren’t recommended. Air ducts get build up of dust, & mold needing periodic cleaning. Having my manufactured home built, I dealt with bias & ignorance against ductlesss mini-splits. Installation was at nearly $2,000 less than an AC installation. The quotes didn’t include duct work since I was forced to allow built-in ducting by the builder. The mini-split is low profile, does both cooling & heating in outdoor temperatures ranging from 30F to 115F. I covered the floor ducts & will turn the dumb thing built inside my livingroom wall, for an old style heat exchanger, into storage. The system works great. While my neighbors’ electric bills run in the $100s during summer months, my average bill is $45 for my 2 bedroom home. It’s quiet, I’ve had it 4 yrs no leaks, smells, gunk, problems, & no maintenace (other than cleaning the filter). I do agree I’d rather not have a line going up the outside wall, but it’s nicely covered and not ugly as what’s shown here. I asked the HVAC installer about two splits. He advised against it because they would compete with each other in my single level home. The guy with the 3 ton and 2 ton units obviously made the wrong choice for his situation. Doesn’t mean mini-splits aren’t adequate. I think there will continue to be a need for AC’s, but mini-splits can be a better choice. Was for me.

  5. Well I have a 3 ton with 3 splits and a 2 ton unit with 3 splits and besides the cost the maintenance is a nightmare! The fan must be hosed off with hot water to get all the funk off! Also 4 of the inside units developed leaks in the aluminum evaporated ! The units would be replaced by Mitsubishi but I would have to pay to extract refig

  6. Well I have a 3 ton with 3 splits and a 2 ton unit with 3 splits and besides the cost the maintenance is a nightmare! The fan must be hosed off with hot water to get all the funk off! Al

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