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Fujitsu and LG Ductless Mini Split Reliability

Bing_Y | Posted in Energy Efficiency and Durability on

I am in the process of adding A/C to my house and I need help with choosing the right equipment. I am update an old 2 story colonial in the Boston area and I am looking to add the ductless heatpump to supplement the oil heating (No gas available on the street). I have the Manual J done and the heat load will be 47000 BTU and the cooling load will be 28000 BTU.

Most installers near Boston MA recommends Mitsubishi Ductless Heatpump due to their superior reliability and part availability. However, these units are very expensive. I was wondering if any can comment about their experience with Fujitsu or LG units since they are cheaper.



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  1. STEPHEN SHEEHY | | #1

    Our Fujitsu RLS3 minisplits have worked flawlessly since installed three years ago. But the availability of good local installers is an important consideration. I'm surprised you find that Fujitsu is cheaper than Mitsubishi.
    And 47000 btus sounds like a huge heat load. Are you sure the Manual J was done using correct assumptions?

  2. Bing_Y | | #2

    Hi Stephen, thanks for your input. For the quote that I got, Fujitsu is slightly cheaper, but LG ones were significantly cheaper. The HVAC company's explanation was the cost of equipment is higher for Mitsubishi units. Labor cost are comparable for all 3 manufacturers.

    As for Manual J, I was also initially surprised by the heating load. But if I remove the sunroom (conversion from enclosed porch in the 1970s) and basement's load, it comes down to about 17 btu/sq ft, which I thought was more reasonable.

    1. mcpascaln | | #9

      Bing Yu, Your post was last year . Please, post here an update and the initial cost provided to you for all the units. I just need to see how much is the cost differences between these brands.

  3. Expert Member
    Dana Dorsett | | #3

    Cold climate Fujitsu XLTH minisplits aren't necessarily much cheaper than Mitsubishi H2i minisplits, but they're pretty good.

    Mitsubishi has the best support network in MA, but Fujitsu training & support seems generally better than LG in this area. One indication of the difference in support level is that there are more Fujitsu "Elite" (more training, more installations) installers in a 20 mile radius of my ZIP code (central MA) than there are LG installers of any training level listed within 25 miles of my ZIP code.

    Getting quotes for three different manufacturers from the same HVAC contractor isn't exactly competitive. Within any manufacturer's line up it's good to get three different proposals or quotes from different CONTRACTORs. I've seen quotes for the same equipment from different contractors come in more than 70% higher than the lower range of bids.

  4. Expert Member
    Dana Dorsett | | #4

    Are you planning to heat & cool the sunroom with a mini-split?

    If not, what are the whole-house heating & cooling loads without the sunroom?

  5. Bing_Y | | #5

    Hi Dana, The current plan is size the ductless heatpump to the cooling load and use ductless heatpump to heat the house until the balance point. If additional load are needed, we will use the oil boiler with hot water baseboard.

    The heating load for the sunroom is 7725 btu and the cooling load is 5360 btu. The heating load for the rest of the house is 35300 and the cooling load is 22000 btu. The house about 2050 sq ft + 220 sq ft of sunroom.


  6. Bing_Y | | #6

    And to answer Dana's question about competitive bidding, we are in a catch-22 situation. We are doing addition and renovation with our GC and he strongly prefers to work with his usual sub contractor, given their relationship. The sub contractor typically install Trane equipment and has also asked me if we would be interested to use Trane SEER 16-17 heat pump, making the whole system dual fuel.

  7. Expert Member
    Dana Dorsett | | #7

    Dual fuel systems with ducted heat pumps rarely saves any money over better class ducted heat pumps sized for the ~95% heat load with auxiliary heat strips to cover the shortfall for the hours that are colder than the 95th percentile temperature bin. Using mini-splits sized for the cooling load works. With dual-fuel it's either/or- the oil burner is running, or the heat pump is running, but not both the same time. With a heat pump + heating strips the heat strips engage while the heat pump is still running. With a right-sized heat pump the lion's share of the heat is still being leveraged with the COP of the heat pump. Oil is cheaper than resistance electric heating, but is not cheaper than a heat pump augmented with resistance heating.

    Oil pricing is also volatile, subject to international politics, wars, and other supply chain issues. Electricity is a regulated market, with downward pricing pressure coming from the increasing levels of zero-marginal-cost renewable power in MA. If you go that route, stick right-sizing the heat pump, backed up with some heat strip, and get rid of the oil tank(!).

    With ~23,000 BTU/hr of cooling load (assuming you're not heating & cooling the sunroom directly) a pair of Fujitsu -12RLS3H would give you a bit more 24,000 BTU/hr of cooling at Boston's 1% outside design temp of 87F, and better than 30,000 BTU/hr of heat @ +12F (Boston's 99th percentile temperature bin). If the Manual-J used different design temperatures than that, what numbers were used? Alternatively, a -9RLS3H + 15RLS3H would have comparable output. x2



  8. Bing_Y | | #8

    Thanks for the advivce Dana! Very appreciated.

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