Results 1 to 12 of 12
  1. #1
    Join Date
    Mar 2007
    Location
    S. Central PA
    Posts
    45

    Mini split ductless cold weather performance

    Does anyone have any experience on the cold weather heating performance of mini splits, especially if a backup heat source is not provided?

    The mini-splits are typically rated as having a rated or nominal heating output at 47F and 17F Dry Bulb per AHRI 210/240. For the sake of discussion a Mitsubishi FE12NA has a stated output rating range at 47F of 3K-21KBTU with a rated capacity of 13,600. What is the difference between "maximum" and "rated"? Is "maximum output" attainable if needed for days or only available for short term as in hours?

    A few of the systems claim they can provide close to 100% of (max?) capacity at 5F such as the Mitsubishi FE12 models (with hyper heating) and they claim max of 13,600 at 17F and 12,500 at 5F. But there again the "rated" capacity is 8,300 at 17F, not the 13,600 that they state is maximum.

    Is "hyper-heating" just a marketing gimmick that allows them to claim a rated maximum output but is not really a usable output? They also claim heat output at -13F is about 58% although no output is provided. The correction factor for defrost is not included.

    Any experience with how Mitsubishi compares with other brands such as the Fujitsu high efficiency single configurations such as 12RLS? Fujitsu does not rate theirs at 5F.

  2. #2
    Join Date
    Mar 2003
    Posts
    7,326
    we use daikins all of the time with no electric heat backup here in pa with no problems. most dont advertise actuak ratings at low temps due to them not having the data. its tough for them to simulate in a lab.

  3. #3
    Join Date
    Mar 2007
    Location
    S. Central PA
    Posts
    45
    Thanks. I was interested in how the single splits worked on cold single digit days with prolonged cold. Sometimes the marketing brochures aren't totally honest.

    Daikin (Quaternity) and Mitsubishi (FE) brag about their single digit temp heating performance and claim having 100% of capacity, while Fujitsu gives heat output only down to 17F, but doesn't say much about output at any temp below that. Not sure about the other brands.

    No HP backup in PA says that Daikin can do the job. Some might say backup is desirable in case of system failure if parts can be a problem. I have friends in upper MN who have always had redundant heating capacity but they need that because of remoteness and frigid winters.

  4. #4
    Definitely go with the Daikin, just do a youtube search for daikin in canada and you will see systems working perfectly at -18F!

    Don't under any circumstance buy a Fujitsu, checkout this posting I did earlier today.

    Fujitsu will not work below 20F at low humidity and their service is horrendus, beware!

    -T

  5. #5
    Join Date
    Feb 2009
    Location
    Home Energy Products: 170 DW Hwy, Belmont, NH 03220
    Posts
    39
    To Suferman, I have probably one of the 1st FD12's in NH I installed in fall 08. For supplamental heat (to my Hot Air) it has saved me much $ on oil. Since it's undersize for my newish 1500 sf ranch, I don't use it under 32 very often but here in central NH it's been great. In the mid 30's it heats the place fine.
    We have been installing the Mits hyperheats since then and have gotten some experience in down to the single dig and neg 0. Not enough to nail it but if you can get the sizing right you can probably get by with most of your heating most anywhere in the 40's latitudes. I have pretty much decided to add a 9FE so I will have cappacity to use as my mainsource down into the 20's.
    As far as Rated Capacity Vs Maximum Capacity, is somewhat confusing to me also. The biggest problem for me is Mits doesn't give the same data at each temp, 47, 17, 5. If I could get this I would be satisfied with our practical experience and Btu / W data to relate it with.

  6. #6
    Join Date
    Jul 2009
    Location
    Fort Worth, Texas
    Posts
    138
    Daikin all the way! We had temps in the teens recently and all was nice and cozy inside. I have many customers with Daikin systems as well and they praise them.

  7. #7
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,594
    We put a Fujitsu in for a family last December. It went through -3 weather just fine keeping the bonus room at 70. Don't know their history, it's only the 2nd Fujitsu we've used and 1st mini heat pump.

  8. #8
    Join Date
    Mar 2011
    Location
    Virginia
    Posts
    93
    If the one you are using is inverter driven, size the unit for your heating load or at least check it to make sure, most of the time the unit will make it.
    I have had a few I have upsized one size to make them work.
    Never had any issues with heat.

    I would not chance doing one without running a load calc though.

  9. #9
    Join Date
    Feb 2011
    Location
    colorado mountians
    Posts
    117
    rocky mountians this winter butt kickin cold. diakins all performed flawlessly. have 17 on differant accounts all good to go whole winter so far

  10. #10
    Join Date
    Feb 2009
    Location
    Home Energy Products: 170 DW Hwy, Belmont, NH 03220
    Posts
    39
    Munc; How long have you had some of these Daikens in for? How are they for servicing, easy to tear down, or haven't they been in that long? How are they with defrost melt build-up, any issues.

  11. #11
    Join Date
    Feb 2011
    Location
    colorado mountians
    Posts
    117
    Some have been in going on three years. without service checker soft ware its kind of a pain workin on them. with serv chkr you get to see all the sensors in system, both cond and indoor unit as well as branch selecter. they have a patch to convert metric readings to u.s. readings. in the condensers you have to be tiny to get to some of the solenoid valves ect. the newer III systems are nice to charge, hook up the 410-A and walk away. the unit will drink till its full then stop takin the juice in. only problem i've had so far is the bypass valve on one condenser was lifting off seat and i had no capacity on that unit. besides that they work great, in the winter heat mode the condenser hot gas defrost was no issue at all. the buildings are running ALC and the interface has been easy as well

  12. #12
    Join Date
    Jul 2005
    Location
    Tulsa
    Posts
    290
    does anyone have feedback on LG ductless mini split heat output performance?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event