Busting Myths on Ductless Mini-Splits

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.

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 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.

To download the infographic in PDF, please click here.

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61 thoughts on “Busting Myths on Ductless Mini-Splits

  1. we have an old 140+ year old Victorian era farm home. The old fuel oil furnace is failing and we have looked at the mini split systems. no duct work to the upstairs and need it desperately. have had 1 estimate at 28,000.00 ( YICKS!!) and am looking at other estimates. will this system keep us cozy (68-73 degrees) in Michigan winters?? air conditioning would be nice, but not really necessary. what are your thoughts??? thank you!!!!

    • We suggest contacting multiple licensed HVAC contractors in your area to get recommendations for what type of equipment should be installed.

  2. I’ve been researching this for months and your site is very valuable. I’m in a 500 sq ft walk-out basement apartment with no ducts, so I think a mini-split might be my best choice – other than a window AC unit and electric heaters in the winter – very expensive options.
    I’ve gotten estimates from $3,600 to $5,800. Why such a difference? What should I be looking for? All are licensed, have good reviews. Of course I lean toward the lowest since I’m retired and on a tight budget.

    • Hi I want to add this comment for anyone interested in a mini split system. I just installed a new Mitsubishi system whole house cooling in 2018 and what I discovered is the systems can make popping and clicking noises at all hours of the day and night due to expansion and contraction of the plastic housing is what I’m told. You can find posts on youtube. If I have to do this again I will strongly consider either in-wall High Velocity ducts or traditional ducts or simply the old-fashioned in wall air conditioning units.

    • We recommend comparing the efficiency difference between the units. High-efficiency units typically have a higher first cost but lower operating costs and may qualify for rebates to offset the higher first cost. We recommend looking up available rebates at http://www.dsireusa.org/

  3. We have lived in our home for over 18 years with no a/c. San Diego has its fair share of hot and humid day. We are at almost 3000 sf, one level. 6 br/4 ba. And our added master is set away from the rest of the main house. I have pondered a Mitsubishi split vs central air. We have 2 more kids at home for maybe another 6 years. My feelings are why have central air to cool the whole house when it will eventually only be 2 of us? Mini splits sound more sensible because you cool the room you’re in, not the whole dang house where no one is! But it is about $15,000 to do 5 zones, to keep the peace (both daughters get a small unit in their room-man cave gets one-master br gets one, and kitchen where we cook). The cost of a new central air system is maybe $8600. And the cost to run either? I have no idea. would love some opinions.

    • We suggest contacting multiple licensed HVAC contractors in your area to get recommendations for what type of equipment should be installed.

  4. I install 12000 btu myself under $700 bucks and amazed at the quietness and efficient cooling.
    They’re also exceedingly energy-efficient. “In the average house, you’re losing 25 percent or more of your energy to ductwork,” says James Bowman, National Technical Manager for RectorSeal and a 20+ year veteran of the HVAC industry. “Simply by removing the ducts, you end up with a more efficient system. Ductless models also have inverter-driven compressors, which speed up and slow down based on the needs of the system instead of shutting off entirely like traditional HVAC compressors do. You consume a lot of energy during compressor start-up.”

  5. With all the conflicting information about HVAC there is no substitute for research (we have computers) and consulting with professionals Remember that finding a contractor that balances their needs to make a living, pay for the business place, tools of the trade, insurance and pay employees, take care of family and pay bills and balances all that with the needs of the homeowner is paramount. Brilliant!

    • After installing mine some one is selling a 12000 btu mini split heat pump for under $500.00 bucks on ebay, dang it, it is very economical when you can do all the work your self.

  6. I am able to do my own work on A/C for my own 108 year old 4100 sq’ home, it’s two stories and attic and basement and located in Southern California. My service box is 200 amps (two legs) 18 years ago I installed a 5 ton service with seasonal energy efficiency rating of 10 it serves the main house (three bedroom annex was added in 1926) while I have extended eaves and a large pecan tree (west side) this home is not well insulated although it has thick plaster walls and 2X6 redwood construction, when the temp reaches over 100 degrees the system runs most all the time, and it eats electricity, what I did to curb the energy monster originally was to put in a few window air conditioners, including one in the living room that I fit into the fireplace and used the flue for exhaust, the condensate flowed down into the clean out box, no problem with that, as the window units began to get noisier and fail I purchased a specific brand of portable units in the 10 to 12 thousand btu range, these fan the air up and down and side to side, and are library quiet, I’ve had great results with these and the seer is much higher, I’ve priced the split systems and they have an even higher seer rating of >20 these seem to be able to save some kwh however they do take up floor space, yet have the opportunity to be easily moved about, for instance when I have the many guests and family over during the summer. We tend to gravitate to the dining, and living room and kitchen. easy to move upstairs units downstairs to take the heat load and it works well. The split systems should prove to take out as much humidity as the central units, perhaps more, as they are localized rather than carrying the humidity back up through the central air intake (many more sq’ of surface for dirt and mold and growths) I have high as 12′ ceiling in the attic and a basement, (hmm, the splits are mostly heat pumps, and as far as losing energy through the line sets, one side is cool, and the other is hot, it should balance very well. There are ductless units that handle 4 zones from one outside unit, these can be mounted to the side of the house, or a small cement pad, of course electricity runs have to be provided, on the outside and the inside could be at the evaporator itself and plug in, from what I see its no more hassle to replace the filter and spray a mold and mildew inhibitor into the inside unit once the front is swung away, just be sure the unit is canted down to drain properly on the outside, I have also seen units that have a cleaning cycle built in and work at the touch of a button and electronic dust catchers and ionizers too. The historical society has approved the units on other homes in the area so no worries there, Solar is coming in and that will be a great savings, The Historic Zone that I am a part of has funding that comes from the sale of environmental pollution credits that are sold by companies who have exceeded their requirement and those are bought by companies that are still working on cleaning up their act, a percentage of that money is put into a fund for (so far) specific Historic District Homes to install solar panels and for a 20 year lease, we will see how that works out. it’s in progress and its taking some time to arrange. Happy trails to you all.

  7. We just had second contractor out to assess/quote on solving our issue with 1950’s single story rancher with collapsed duct work, oversized condenser, no crawl space in attic, etc., etc. First contractor did load capacity measurements and put for a plan for a hybrid solution … smaller ducted unit for bedroom zone and ductless mini-head in open areas $18,800. Then 2nd contractor said ductless mini-heads aren’t efficient at eliminating humidity and is suggesting cutting holes in ceiling to replace ductwork and since the ceiling will be open, also foam insulate attick and replace CPVC plumbing – $50-60K. Obviously the *extras* are option, but the commentary about the mini-heads is the problem. We’re no experts. WHo do you believe when you *expert* endorses/recommends and another *expert* doesn’t recommend? Good Lords.

  8. We have been introduced to multi-head ductless systems today. Had A/C contractor to our new (older) home in northern Florida to inspect HVAC. Home is 2100 sq ft single story rancher built in 1956. The roof pitch is barely existent. The duct work is crushed in spots, deinsulated in others. Bottom line, the duct work needs to be replaced but the space is too small to navigate. On top of it, plumbing has been re-done and is now in this tiny space with CPVC pipe. There is about 3′ of clearance and no way to avoid the CPVC plumbing. One option presented is the multi-head system. I had never heard of them and am wondering what this does to our home’s resale value? There is currently a 5 ton unit in the house, but no way to correct the issue with the ducts short of removing the roof.

    Help

    • I had my first unit installed 8 years ago. My primary problem then was cooling. I have a high ranch and upstairs would get extremely hot. Had the tech come in and he suggest I get the heat/ac….I did. Have never been sorry and actually today had the tech come today and I am having a larger unit and another head put in for the lower floor apartment. I am very happy with the unit. Now my daughter is getting one to. Very inexpensive to run.

  9. HI Frank,
    Have a raised ranch with no ductwork. Concerned about the mini splits not allowing for even cooling thru the house. Can find no information on how these systems work for this type of home. However installing flexible ductwork may prove to be cost prohibitive. Can you comment on the splits ability to cool more than one room in a single story home?

    • HI Kathy – you are correct in your concern about air movement in a multi-level home like your raised ranch design. The reason for this is that hot air rises and cold air falls so the need to manage the air flow within these separate zones is important. The simple answer is that you could install a multi-evap mini-split system with a separate cooling unit for each of the major zones. In most cases a single cooling unit will only cover the local area (room or rooms) close by and will not provide much cooling beyond that. With a multi level home this could be even more difficult. There are other articles and posts on this site that deal with the pros and cons of ducted versus ductless systems so you might try reading those. Once you are ready to talk to some contactors, you might try getting quotes for both styles to see which ones might work best for you. There are ways to get ductwork installed that are not too invasive but you might have to talk to a few different contractors. Be sure to ask them about the air movement from room to room which might also be important for air filtration and humidity reduction if you are in a climate where these might become issues. You might also ask them about using ceiling fans or whole house fans to mix the conditioned air in the various levels. I hope this helps answer some of your questions. Thanks for using our site!

  10. Hi,
    I am adding a game room in Houston, TX. in a house that has been raised 5 feet (to prevent flooding). My current central a/c is maxed out for the original floor plan of 2,675 sq. ft.

    The new room being added will be about 550 sq. ft in total with windows and a 12 foot sliding glass door facing West.

    Considering adding a split a/c unit. Houston has high humidity in summer time. The house is 52 years old.

    Appreciate any comments. Thanks
    Sid

    • We recommend contacting a local licensed HVAC contractor in your local area to have them properly determine your heat load and then they can provide unit recommendations.

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