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Mitsubishi Ductless Mini splits

Crissie
Crissie Member Posts: 132
You all are such experts, what is your opinion of the Mitsubishi Ductless hyper heat mini splits?

Comments

  • GW
    GW Member Posts: 4,692
    We install about 100 outdoor units and several hundred indoor units a year, might you have a more pointed question?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • Crissie
    Crissie Member Posts: 132
    GW said:

    We install about 100 outdoor units and several hundred indoor units a year, might you have a more pointed question?

    Are customers generally happy with them? Do they find that conditioned air reach the other side of a room, for example in a 19 x 13 ft room, putting it in the middle should be adequate?
    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.
    I had a consultant tell me I would need to deep clean each unit's head once every 6 months, that mold can develop in them. By deep clean, I mean take the blower wheel out, takes about 1 hr. He did clean the little tiny filter every few weeks. Have also spoken with users in FB groups who had waited 18 months and the head was filthy, caked with dirt.
    Thank!
  • GW
    GW Member Posts: 4,692
    edited October 2021
    Opinions galore out there, like everything else these days. Our customers love them.

    Size of room-I can't visualize the space you're describing well enough to have an opinion. Is this mainly for ac or heat or both? Ac tends to flow pretty well, but heat can drift as it gets colder and colder outdoors. I would think in a room that size (not that big), put it wherever you want. I generally want to see the units blowing the 'long way' (put it on the 13' wall if possible). I would not really want to put this in the middle of the 13 foot wall (if you want good circulation). It will work, but not as well.

    if your home is relatively clean and you do a good job cleaning the filters (homeowners must clean their own filters, or pay unnecessary fees to have a pro do it), that 'deep clean' advice is too aggressive.

    Electricity----don't yo-yo the settings, set it and forget it. These units draw lots of power when they 'wake up'. They sip power when they are just left alone.

    filthy after 18 months----not normal, I would be curious what kind of environment they were in. I'm on Massachusetts, but maybe in other climate zones my comments would not be accurate.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • pecmsg
    pecmsg Member Posts: 4,842
    edited October 2021
    Crissie said:

    GW said:

    We install about 100 outdoor units and several hundred indoor units a year, might you have a more pointed question?

    Are customers generally happy with them? Do they find that conditioned air reach the other side of a room, for example in a 19 x 13 ft room, putting it in the middle should be adequate?
    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.
    I had a consultant tell me I would need to deep clean each unit's head once every 6 months, that mold can develop in them. By deep clean, I mean take the blower wheel out, takes about 1 hr. He did clean the little tiny filter every few weeks. Have also spoken with users in FB groups who had waited 18 months and the head was filthy, caked with dirt.
    Thank!
    The issues your describing are generally due to drastically oversizing. Yes they can and do ramp up and down over a wide range but still need to be properly sized for the max. Dehumidification drops as the capacity drops and that can cause the mold growth.

    We switched to Fujitsu years ago. Mitisi were a little too pricy.
    Crissie
  • SuperTech
    SuperTech Member Posts: 2,155
    Crissie said:
    We install about 100 outdoor units and several hundred indoor units a year, might you have a more pointed question?
    Are customers generally happy with them? Do they find that conditioned air reach the other side of a room, for example in a 19 x 13 ft room, putting it in the middle should be adequate? Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people. I had a consultant tell me I would need to deep clean each unit's head once every 6 months, that mold can develop in them. By deep clean, I mean take the blower wheel out, takes about 1 hr. He did clean the little tiny filter every few weeks. Have also spoken with users in FB groups who had waited 18 months and the head was filthy, caked with dirt. Thank!
    Every single mini split system that I see, regardless of make or model is a disgusting mold bucket after two years. This is my biggest problem with these systems. Some minis are a nightmare to disassemble and clean. Second biggest problem is that they are a nightmare to troubleshoot and service,  proprietary parts are not always available.  I wouldn't recommend depending on a mini split as my only option for heating in a cold climate. I've seen too many people regret getting rid of a reliable cast iron boiler due to these issues. 

    I would only go with a mini split if it was not possible to install ductwork or If I couldn't afford a proper ducted system.
    CrissieSTEVEusaPA
  • Crissie
    Crissie Member Posts: 132

    Every single mini split system that I see, regardless of make or model is a disgusting mold bucket after two years. This is my biggest problem with these systems. Some minis are a nightmare to disassemble and clean. Second biggest problem is that they are a nightmare to troubleshoot and service,  proprietary parts are not always available.  I wouldn't recommend depending on a mini split as my only option for heating in a cold climate. I've seen too many people regret getting rid of a reliable cast iron boiler due to these issues. 

    I would only go with a mini split if it was not possible to install ductwork or If I couldn't afford a proper ducted system.

    SuperTech Are they worst with mold than PTAC units? Thx!

  • GW
    GW Member Posts: 4,692
    @pecmsg you kinda simplified a very technical conversation. ANY "multi-zone" is oversized at any give moment, right? It you have a (pick a number, lets say 3) 3 zone system but you're calling on only one zone, Bang---you're automatically oversized.

    Single zones----I always try and pitch the pros of singles...they simply can do more work with dehumidification, versus the bigger multis.

    Lastly- I think when people yo-yo the ac temp setting and allow the house to load up with humidity---it's a downhill slide.

    These systems are nails in our area---not sure what else is going on out there. My bus is very happy
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
    CrissieMarkShean
  • pecmsg
    pecmsg Member Posts: 4,842
    I stopped selling anything over Duel Zone years ago. Single or duel. 
    That was one of the reasons. 
    Crissie
  • GW
    GW Member Posts: 4,692
    right on- gotta wonder if they are yo-yo's
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    gary@wilsonph.com
  • pecmsg
    pecmsg Member Posts: 4,842
    edited October 2021
    I heard a lot of stories :O they can ramp up and down as needed" too a point. I have a tri zone in the summer house. Last one we installed. 3- tons for 1000 Sq Ft. East walls are all glass, no floor insulation, 2X6 roof decking exposed all open. It maintains 72 - 74° in the summer but is running 80 - 90%. No mold issue. filters need cleaning 2 - 3 times a season.

    in hind site i should have installed a Single 1 1/2-Ton for the main living area and a 1 1/2 ton ducted for the 2 bedrooms
    Crissie
  • Crissie
    Crissie Member Posts: 132
    pecmsg said:

    I heard a lot of stories :O they can ramp up and down as needed" too a point. I have a tri zone in the summer house. Last one we installed. 3- tons for 1000 Sq Ft. East walls are all glass, no floor insulation, 2X6 roof decking exposed all open. It maintains 72 - 74° in the summer but is running 80 - 90%. No mold issue. filters need cleaning 2 - 3 times a season.

    in hind site i should have installed a Single 1 1/2-Ton for the main living area and a 1 1/2 ton ducted for the 2 bedrooms

    3 tons for 1000 sq ft, how many indoor heads did you use? thx
  • pecmsg
    pecmsg Member Posts: 4,842
    3
    Crissie
  • rsilvers
    rsilvers Member Posts: 182
    edited January 2022
    By multi-zone, you mean one compressor with multiple heads?

    Are you saying this drops efficiency because the large compressor has to run?

    How would you do an entire house if not for multi-zone systems? A compressor outside of each room wouldn't be reasonable.

    MA has a $10,000 rebate if it covered enough BTUs for the only source of heat.
  • rsilvers
    rsilvers Member Posts: 182
    edited January 2022
    Crissie said:

    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.

    Of course. Anything that was an oil or gas bill is now an electric bill. The cost to heat with heat-pump in MA is twice that of the cost of natural gas, and about the same as oil or propane. You can only really save if you have solar or were using electric resistance heat.

  • pecmsg
    pecmsg Member Posts: 4,842
    rsilvers said:

    Crissie said:

    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.

    Of course. Anything that was an oil or gas bill is now an electric bill. The cost to heat with heat-pump in MA is twice that of the cost of natural gas, and about the same as oil or propane. You can only really save if you have solar or were using electric resistance heat.

    I disagree. The cost of "operating" a Heat Pump during Most of the winter is less then oil or NG Forced air.
    Hyper Heat is even better ag below 0°F.

    https://www.amsenergy.com/fuel-cost-calculator/
    Hot_water_fanSuperTech
  • wmgeorge
    wmgeorge Member Posts: 222
    It depends. The cost of oil or gas may be cheaper than running a mini HP, it depends and you need to do some calculations. My Hyper Heat Mini struggles when outside temp drops to zero or wind chills are high.

    The cheap see through filter that came with my Mitsubishi was cleaned a Lot but after 2 1/2 years the blower wheel was plugged. Why are you removing that wheel to clean? Its not a easy job, I used compressed air and then needed to clean up the area with the shop vac, sorry honey. ;( They sell in place cleaning kits and powered sprayers to use. I have now a sprayer with canister for soapy water or whatever powered by compressed air. It fits right through the vane openings and you can get to the wheel.

    I now have some washable filter coat to try. Its my understanding this is a once every two year or so job to clean the blower wheel so if this filter coat works, yeah.
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • SuperTech
    SuperTech Member Posts: 2,155
    I don't work on many PTAC units so I can't really say how they compare. I have used the bib cleaning kits for the ductless indoor units and they work well if you use a battery powered Coil Jet sprayer. However, this can also be a messy process and requires the use of drop cloths and plastic sheeting to protect the walls and floors.
    Mitsubishi units are usually a little easier to deal with. I take the covers off and drop the drain pan down and manually clean the buildup on the blowers with a brush and vacuum. 


    wmgeorge
  • Jamie Hall
    Jamie Hall Member Posts: 23,275
    Seems to me a lot of the problems which I read about -- not just on the Wall -- and see come from one of several areas. First, you need to size them correctly. Either under or over and the customer is not going to be happy. Second, don't oversell them. If you are selling one to provide heat at 0 with a 30 mph breeze, it may work -- but it will be a struggle. The customer won't be happy. If they are in an area with power outages, the customer may not be really ecstatic about having to have a really big generator -- which may not allowed anyway. Third, don't tell the customer they are going to save money. Unless the electric rates are really low or they are switching from electric resistance, they are going to spend more money on heat. And the customer won't be happy.

    That said, it looks like things are going that way in general. Just try to avoid being the lightning rod.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    wmgeorge
  • rsilvers
    rsilvers Member Posts: 182
    pecmsg said:
    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.
    Of course. Anything that was an oil or gas bill is now an electric bill. The cost to heat with heat-pump in MA is twice that of the cost of natural gas, and about the same as oil or propane. You can only really save if you have solar or were using electric resistance heat.
    I disagree. The cost of "operating" a Heat Pump during Most of the winter is less then oil or NG Forced air. Hyper Heat is even better ag below 0°F. https://www.amsenergy.com/fuel-cost-calculator/

    I said “in MA.”

    Oil would have to be $3.50 a gallon for it to be as expensive as a heat pump when you pay 0.223 for electricity. 

    Oil was under $2 a gallon before Covid was used as an excuse to transform government. 

    Even now, I am paying $3 for oil, so heat pump will cost more. 

    So why do I plan to add mini splits? Partly because our vacation home has no AC and ducts are hard to add unless we do a lot of invasive work on the finished basement and garage. Partly because I plan to get solar and so electric will be pre-paid in the form of the subsidized generation hardware. 
    wmgeorge
  • wmgeorge
    wmgeorge Member Posts: 222
    rsilvers said:


    pecmsg said:

    rsilvers said:

    Crissie said:

    Do their electric bills go up substantially for heating use costs? I have heard complaints on this by a few people.

    Of course. Anything that was an oil or gas bill is now an electric bill. The cost to heat with heat-pump in MA is twice that of the cost of natural gas, and about the same as oil or propane. You can only really save if you have solar or were using electric resistance heat.

    I disagree. The cost of "operating" a Heat Pump during Most of the winter is less then oil or NG Forced air.
    Hyper Heat is even better ag below 0°F.

    https://www.amsenergy.com/fuel-cost-calculator/

    I said “in MA.”

    Oil would have to be $3.50 a gallon for it to be as expensive as a heat pump when you pay 0.223 for electricity. 

    Oil was under $2 a gallon before Covid was used as an excuse to transform government. 

    Even now, I am paying $3 for oil, so heat pump will cost more. 

    So why do I plan to add mini splits? Partly because our vacation home has no AC and ducts are hard to add unless we do a lot of invasive work on the finished basement and garage. Partly because I plan to get solar and so electric will be pre-paid in the form of the subsidized generation hardware. 

    ================================================
    Our Hi 2 Mitsubishi does very well down to 10 degrees F. Its installed in a poor application for a HP, but since we only pay about 10 cents kW it does ok. NG would have been my choice but we needed AC also.

    Those bib or kit type cleaners as I understand work well. IF the mini's would have been designed for a real filter it would be a moot point. I have high hopes for that filter coat spray, time will tell.

    Feel sorry for you Eastern folks seems your seeing the worst weather.... again.


    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • wmgeorge
    wmgeorge Member Posts: 222
    edited January 2022
    Our Mitsubishi Hi 2 does well until below 10F, but our cost per kW is only 10 cents. You need to calculate your fuel costs before deciding which is better. PS the calculator linked above has a Big flaw, Natural gas furnaces like mine are 96% Eff not 85%! When I was teaching the one we used you can vary it all.

    Those Mini split cleaning kits do well as I understand. But it would all be a moot point if they would have been designed to use a good filter from day one. I am hoping my filter coating spray will help.
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • Condoman
    Condoman Member Posts: 90
    I am in SE CT and added Fujitsu units in 2019 & 2020. 3 bedrooms on 1 unit and dining and living on another. Began A/C use in 2019 then went heat pump use in 2020. Electric bill went up, no surprise. Oil bill went down, again no surprise.

    Have annual maintenance done and clean my filters three times per year. Refuse to pay for stupid little air cleaning filters because of the price. There is no way those things are worth the cost.

    Also have burner maintenance done annually since I do not want trouble in the heating season. Still use oil for DHW so, I know no critters will move into my chimney in the off season.

    We generally leave all wall units at 70°'s although one might push to 74°'s if the room feels cool during heating season.

    The oil heat is set to 68° and almost never cycles on, it's set as backup.

    Only issue so far was failed fan in 2019 outdoor unit after 20 months. I was able to diagnose with LED flashing indoor lights. Parts covered under warranty, labor not so much.
  • wmgeorge
    wmgeorge Member Posts: 222
    Ok with much Searching I found this Excel file on the State of Maine website, download and try to see if it works for you to compare fuel costs.
    Old retired Commercial HVAC/R guy in Iowa. Master electrician.
  • SuperTech
    SuperTech Member Posts: 2,155
    The bib kits work well, but make a big mess and are a pain to setup and use. Just my opinion but I don't want my heating and cooling coming from units with moldy looking black growth in them. 
    wmgeorge
  • gyrfalcon
    gyrfalcon Member Posts: 162
    I had a 1 ton h2i Mitsubishi put in my 10x30 sunroom with open door to mud room. All south facing , angled glass.  So far it has been great.  Sure , it runs all the time, sometimes barely at all, other times full blast. I live in south central Indiana. Electric bill has gone up 10-20 bucks a month but that room is now pleasant to be in, so it’s worth it . Plus, on sunny winter days the fan still blows and moves the very warm air into the rest of my bermed home, so boiler doesn’t turn on. It was a good choice for us, who knows what will happen down the road if we have problems or failures.  In my area Mitsu is most supported.  Daikin would be second place, support wise.  

    My boss just had a 3 head system put in his daughters house, it was an American Standard / Mitsubishi brand.  So far so good .  
    Slant Fin Galaxy GG100(1986) , 2 zone hot water baseboard, T87 Honeywell thermostats. 
  • bignozzle
    bignozzle Member Posts: 23
    I just put in a Mitsubishi 12k hyper heat. I’m in ct. almost to the mass line. It’s in a 450 sf. Room with a lot of glass. For the month of December, it raised my elec. bill $130. My whole heating space is 1350 sf., and except for the room with the mini split is basement(1 wall exposed to the elements). I was using 4 bags of pellets every 3 days in a stove in the basement area, plus oil baseboard in the glass room. The pellets were costing over 200 a month plus the oil. In December it wasn’t too cold but did see some high teens. I used only the mini split to heat for the entire month and maintained 67-70 except for 1 bedroom which stayed at 62-64. I am really pleased so far. We just had a good snow and the mini split could only keep it at 64, because it was defrosting more often. I was thinking of some type of enclosure to keep the wind and ice off. Has anyone got any experience with that?
    Thanks
  • pecmsg
    pecmsg Member Posts: 4,842
    bignozzle said:

    I just put in a Mitsubishi 12k hyper heat. I’m in ct. almost to the mass line. It’s in a 450 sf. Room with a lot of glass. For the month of December, it raised my elec. bill $130. My whole heating space is 1350 sf., and except for the room with the mini split is basement(1 wall exposed to the elements). I was using 4 bags of pellets every 3 days in a stove in the basement area, plus oil baseboard in the glass room. The pellets were costing over 200 a month plus the oil. In December it wasn’t too cold but did see some high teens. I used only the mini split to heat for the entire month and maintained 67-70 except for 1 bedroom which stayed at 62-64. I am really pleased so far. We just had a good snow and the mini split could only keep it at 64, because it was defrosting more often. I was thinking of some type of enclosure to keep the wind and ice off. Has anyone got any experience with that?
    Thanks

    Do NOT block the free air flow. Snow, Sleet, rain do cause more defrosts. It's the nature of the beast.
    1-Ton for 1300 Sq Ft in your area is a little small. Get a 2nd unit and those issues might go away.
  • bignozzle
    bignozzle Member Posts: 23
    I was looking at shields that go in front of the unit but still leave room for air circulation. Would probably help some. I think I will put another unit in later this year. This is my first unit I wanted to see how it worked before putting a second.
  • pecmsg
    pecmsg Member Posts: 4,842
    That unit is moving roughly 300 - 400 CFM of air at full speed, anything you build WILL restrict it.