Which company makes the best mini-split heat pump systems right now?
LBrittBrattleboro
| Posted in Mechanicals on
Of the following 3 manufacturers which is considered to be the best quality. We live in southern VT and all of them are rated for as low as -15f : Daikon, Mitsubishi or Samsung.
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You might find better replies if you define "best". "Best" to me means the ability to modulate very low. It might mean which unit consumes the least energy to someone else, or maybe the lowest cost set to another.
Of those 3, Mitsubishi. I would consider Fujitsu too. Mitsubishi is like the Cadillac. They have great thermostats with remote temp sensors as well. The Fujitsu are great as well and in some cases better heating/cooling wise but thermostat options are not up to what Mitsubishi has. Fujitsu can also be harder to get parts down the road than mitsubishi fyi. Depends what you want...if you want slim duct get the Fujitsu. 6k or 9k wall unit I'd get Mitsubishi. 12k Fujitsu or Mitsubishi...edge to Mitsubishi. 15k I'd get the Fujitsu unless you already have Mitsubishis...downturn is much better there.
Also the Fujitsu outside units are much smaller in some cases fyi.
I've installed both and will say the Mitsubishi quality is a little higher.
The biggest factor is the installer and how well they did their job.
Very good equipment install poorly is almost useless and if you select the best installer, they will refuse to install anything they can’t make run well.
I say talk to your friends and neighbors and go have a look. I think most people can tell from a look a good install from a rush job.
Stay away form the units with multiple heads attached to one outdoor unit.
Walta
I was considering installing two external units with 4 internal units each. Why would you stay away from that?
Nothing wrong with them if installed right. They definitely have their limitations and less efficient. Check what the outdoor unit can run down at. They'll often run at min trying to satisfy one room and shoot any extra coolant to other head when those rooms are off...since they have to. Some of the Mitsubishi run pretty low BTU wise. Some of the units really don't turndown much though.
I am planning on using Mitsubitshi. All in ceiling cassettes, which may be oversized in some places since the smallest is 9k.
I made sure the indoor units can spin down pretty efficiently, didn't check outdoor.
Some people have reported that for multi-splits, the indoor units don't modulate at all and simply run at their max output if they are on. I don't know if that's correct or not, but it's oft repeated around here.
What I do know is correct is that, even when one IDU is not calling for heat or cool, refrigerant is flowing through the pipes 100% of the time, so you get some residual heating and cooling in every zone -- including the zones that are not calling for heating or cooling. People here have complained this can cause those zones to go several degrees above or below setpoint.
Look into Gree, they are good down to -30ish and have a much better warranty than the others. That is what I will be putting into my house in Northern NH
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In what way is the warranty better?
All of them can be good, from both a reliability & performance point of view, but it depends on both the model and how properly sized it is to the load.
They all SUCK if oversized.
Daikin's cold climate units are every bit as good as (or better than) Mitsubishis. An important decision factor is how much local distributor & installer support there is. In southern NE Mitsubishi dominates, and Daikins are rare, but on the Maine coast Daikin has a real presence.
I'm told (but have yet to personally verify) that (like Carrier, and others, including Gree) all recent Samsung units are re-badged Midea units, or at least most of the subcomponents under the sheet metal are Midea. Midea is a large Chinese conglomerate who got into bed with Toshiba a couple of decades ago when Toshiba was interested in building a refrigeration compressor factory in China. The joint venture has resulted in top of the line technology at competitive pricing, and in recent year Midea moved into the #1 slot world wide in annual AC & heat pump production. Some of their cold-climate models are truly top shelf in quality & performance, some of their down-market stuff perhaps not so much.
By far the most important thing is to get the sizing right. Most contractor derived Manual-J load numbers are crap, another garbage in = garbage out problem, with an all too human internal bias toward oversizing "...just to be sure...". While this is sorta-OK for gas/propane burners, oversizing delivers a more severe hit to comfort & efficiency with heat pumps- even modulating heat pumps, since modulation ranges are not infinite.
The NEEA consortium of utilities in the Pacific Northwest got huge feedback from unhappy ratepayers/customers from their heat pump conversion programs a decade or so back, with an overwhelming majority of the issues being attributable to woefully oversized equipment. To address those issues they developed an free, easy to use load tool (and duct design too) targeted at HVAC contractors giving them both some cover (if undersized) and NO EXCUSES for oversizing. This tool is freely available for any one to use, and I highly recommend using it (don't even try to convince your contractors to run it), and come up with your own list of appropriate models to use. You'll have to share an email to get it, but it's totally free, and they make it harder put your thumb on the scale. See:
https://betterbuiltnw.com/hvac-sizing-tool
Once you have the load numbers for the rooms/zones you are trying to cover, you can search for models by vendor and +5F output (using the sliders on the upper right) on the NEEP websize (which Efficiency VT recommends) here:
https://ashp.neep.org/#!/product_list/
While it's sometimes OK to oversize by as much as 50%, try to keep it to under 1.25x the load, and always take a look at the MINIMUM output (and efficiency at that minimum modulation level) at +47F (the standard AHRI test temperature) to compare apples to apples. An oversized unit with low efficiency at minimum modulation is going to underperform an oversized unit that has high min-mod efficiency. A unit that can modulate lower at +47F will generally be more comfortable that one with a higher minimum output, since it's running nearly constantly rather than cycling on/off, which results in higher temperature swings and a bit of wind-chill effect.
I recently used the BetterBuiltNW tool to specify a 1-ton cold climate Daikin as a replacement for a now dead but oversized 1.5 ton Mitsubishi. A week after it was installed the homeowner expressed concern that there might be something wrong with it, since it never seemed to cyclic off. Looking at the weather history for her location it hadn't gotten warmer than the low 50sF in that initial period, and being right-sized it SHOULDN'T have been cycling. The dead unit (the venerable Mitsubishi FE18, a great piece of equipment for it's time if right sized) has a minimum modulation at +47 nearly twice that of the new Daikin, and according the homeowner would cycle on/off regularly even at 30F outdoors.
The 1-ton Mitsubishi FS12 would have worked just fine there as well, but the quotes were coming in $1500-$2K higher than the Daikin. (We requested a quote on a 1-ton Fujitsu as well, but the contractors never responded.) The Daikin 12QMVJ's mini-modulation @ 47F is4400 BTU/hr , to the Mitsu FS12's 3700 BTU/hr, but it's efficiency at min-modulation is higher than the Mitsubishi, and the capacity at +5F is a bit higher. Both are GREAT units:
https://ashp.neep.org/#!/product/34607/7/25000///0
https://ashp.neep.org/#!/product/56996/7/25000///0
Bumping it up to a 1.25 tonner or 1.5 tonner will in most cases would result in minimum modulation levels north of 5000 BTU/hr @ 47F, resulting in lower efficiency and lower comfort at a higher up front cost.