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Gree Minisplit Performance Numbers – too good to be true?

Matt_Michaud | Posted in General Questions on

We have a 24K multi unit spec’ed for a DER in northern NH.  In the original contract the unit was said to be the Fujitsu AOU24RLXFZH.  The contractor is now switching HVAC companies and the new installer wants to go with a Gree unit – likely the Multi 21+ 24MBH.  My understanding of this is that its a downgrade from a tier1 Japanese manufacturer to a tier2 Chinese manufacturer targeting big box stores.  Checking if the numbers supported my assumption, I compared the manufacturers’ performance tables.  At -5F and 70F indoors, Fujitsu says 17550 BTU/hr and 2830W for a COP of 1.82.  Gree says 16563 BTU/hr and 1543W for a COP of 3.15.  Gree’s COP at -5F even barely drops to 2.67 with an indoor temp of 90F (not relevant to our application obviously, but surprising)!  Why the major difference?  Can these tables be trusted?  If not, how can I compare performance realistically?  

https://www.greecomfort.com/wp-content/uploads/2019/09/GREE_MULTI21_C_SUBMITTAL_24MBH_090319.pdf

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Replies

  1. this_page_left_blank | | #1

    Short answer: Yes.

    When numbers look suspicious, the first thing I do is look for incongruities. There is a glaring one in the attached link. With COP numbers like they list, all above 3 for all temperatured -5F and up, one would expect a very high HSPF but it's not. It's only 11.

    Going one step further, compare the numbers in their document to the data on NEEP's product listing. They don't match. The NEEP data only goes down to 5F, so let's compare the numbers there. Gree's literature says 17kBTU/h and 3.17 COP. NEEP says 18kBTU and 1.81 COP. I don't know exactly what, but something fishy is definitely going on.

    1. joshdurston | | #2

      To expand on what Trevor said, I tend to favor the HSPF as a more comparable number. When all else is equal go with the HSPF instead of COP for comparisons.

      The COP numbers are taken at a specific capacity/% at specific indoor/outdoor conditions. The NEEP data does attempt to show the COP at various loads.

      But with HSPF some smart people have already done the math. There are correction table based on your actual location available.

      The HSPF is based on a climate zone (usually Zone 4 but I've started to see some Zone 5 data here in Canada). This corrects for the varying loads and time spent at various OA conditions, as well as defrost, and pan heaters (if they're factory installed).

      1. Matt_Michaud | | #4

        Looking at the AHRI certificates to compare HSPF, I found that Gree's HSPF is 10.5 (apparently they just round that up for marketing material), still higher than Fujitsu's 10.3 or Mitsubishi's 10.0. The kicker though, is that the MULTI model with the rosy COP numbers was the HP230V1CO which AHRI said was discontinued and they now make HP230V1DO. That model, when looking at performance tables, has much lower COP at low temps - like 20% lower than Fujitsu. The world makes sense again.

  2. jackofalltrades777 | | #3

    You get what you pay for. GREE tends to be low quality for a low price.

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