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minisplit ductless heat pump

Post in 'DIY and General non-hearth advice' started by Highbeam, Feb 6, 2013.

  1. begreen

    begreen Mooderator Staff Member

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    They have some undefined terminals like input 1 and 2. Our system has an outdoor thermocouple so that the heatpump cycle and system speed can be tailored by the difference between the exterior in indoor temp. This function appears to be lacking or did I miss it?

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  2. eclecticcottage

    eclecticcottage Minister of Fire

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    We're still considering this for our Old House, leaving the two DV stoves in place as secondary heat (or primary depending on the tenants choice). I'm still concerned about cost though...

    Actually, we're thinking of putting a two head unit here at the Cottage too. Cost is still a concern, but a little less since we don't need to worry about recouping it :)
  3. SCHWIL

    SCHWIL New Member

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    I own a house built in 1750. It is a true brick house (no wood frame). Right now I have a 30 yr old hvac system that runs on LP, and it's costing me a fortune summer and winter, alike. I would love to get rid of the duct work, the blowers dripping condensation from the attic, etc. Does anyone have any thoughts about the practicality and/or efficiency of replacing the dinosaur with a mini-split system?
  4. woodgeek

    woodgeek Minister of Fire

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    Where are you located?
  5. SCHWIL

    SCHWIL New Member

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    My 1750 house is in Hampton Roads, VA. The thick brick walls act as a cave--cold in the winter and moderate in the summer. The addition is wood frame and has the usual concerns. The system we have now is ancient and must be replaced no matter what. I just wonder if this is a rational option.
  6. pen

    pen There are some who call me...mod. Staff Member

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    Since putting one of these ductless units in many rooms would be an eyesore, and expensive, the layout of the house is often a large determining factor in how well these things will work.

    After having such great success with my unit I had a cousin who was interested in them to help take the edge off his oil usage. My installer went to his house and told him "I'm not selling you one of these, this place will give them a bad name." His house was about 100 years old with tall ceilings and was a very non-open layout.
  7. SCHWIL

    SCHWIL New Member

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    There are 4 rooms in the old brick part of the house and 2 rooms in the addition which is wood frame. I have read about ceiling vents that would probably work upstairs. I don't know if that would work downstairs as the ceilings are 9 feet. I would prefer ceiling to wall-mounted systems. The layout is definitely NOT open, but it seems like that would make the room by room conditioning concept better??? There is a company here that advertises 8 splits on one system, but I don't know the cost. Do you have any alternative suggestions for heating an historic house like this?
  8. pen

    pen There are some who call me...mod. Staff Member

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    I think your best bet is to talk to an installer that you have good references for.

    At the end of the day, the expertise on this site is in regards to solid fuel burning. You just happened to come across a thread where a bunch of us were basically shooting the breeze about these things in terms of our experiences
  9. woodgeek

    woodgeek Minister of Fire

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    Another option would be conventional split system, like a central AC system. Sounds like your ducts need to be replaced or sealed/insulated (at least in the attic or other unconditioned space). If fixing the ducts was doable, could be a lower cost option. Without the open plan or high insulation level, minis might not be ideal.

    Efficiency might be a bit lower, but in VA you'd prob be fine. I'm running a Goodman 4-ton ASHP effectively in Philly.
  10. flyingcow

    flyingcow Minister of Fire

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    On that note i just put in 2 mitsubishi's Hyper's. Nice units, we love 'em.
    pen likes this.
  11. begreen

    begreen Mooderator Staff Member

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    Congrats. Let us know how they work out this winter.
  12. Highbeam

    Highbeam Minister of Fire

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    Here I am again, almost a year later researching these things again during a burn ban. I have mental issue I guess and only get serious when I am faced with being cold.

    The minisplit market seems to have remained unchanged with the same technology and same players. Thoughts?
  13. flyingcow

    flyingcow Minister of Fire

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    At this point I am happy with my units.
  14. pen

    pen There are some who call me...mod. Staff Member

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    Love the poo out of mine but only 1.5 years into service with my mitsu unit. I still can't get over how comfortable it makes things in the summer, and even how much I use it in the shoulder season (BG called it) and how little the darn thing costs to do all that. At most using the 18k cooling 22.5 (or something similar) heating unit I have (with hyperheat) has been about 15 bucks a month.

    I used to use a 6 foot electric baseboard intermittently to supplement in shoulder seasons or when I was going to be away from the stove. Setting the mitsu unit to keep the house at 65 and keeping it there (or higher when wanted) costs about the same a month and does way more than that little 6 foot unit did.

    Very happy, and hope I can keep saying that year after year.

    I do have a couple of minor gripes (fan runs more than necessary, temp setting is inaccurate for heating) they are mild.
  15. peakbagger

    peakbagger Minister of Fire

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    The Mitsubishi units are the standard for these type of units. Fujitsu made a big PR campaign in central maine to go after Bangor Hydro rebates. Both have good reputations. Both can be installed poorly and there are shortcuts that are easy to take. Cold weather heat pumps need to be out of the wind, preferably on the downwind side of the house in place where snow doesn't fall on it. This unfortunately is opposite of a desired place for an AC unit so there is a fundamental trade off on the optimal location of the unit. I built a removable pitched roof over mine to keep snow off the coils but its not optimized for sun. The ideal spot would be on south wall shaded by a hardwood in the summer that loses its leaves for the winter. There are flush mount wall and roof options for those who don't like the look of the standard wall mount unit. There are several second tier brands, usually slightly less efficient or not as effective down at low temps. Mitsubishis can be bought on line, I am not sure if Fujitsus are. Both companies predominantly want to sell through distributors and installers with significant makrups.

    From talking with service techs, there are very rarely serviceable components that are worth fixing unless the unit was a defective design. The construction is very tightly packed and generally its easier to swap in a new unit due to labor costs. Usually repairs are driven by poor installs or external damage.

    I did my own install and hired out the final charging of the lines. After watching what needed to be done, I will probably charge the lines myself next time , but the one time cost for a pump and gauge set means if you only install one, hire it out.

    Tom in Maine on this site gets a lot of feedback on these units on his radio show, unfortunately unless you live near the radio stations, there is no way to hear them but his two cents would be valuable.
  16. firefighterjake

    firefighterjake Minister of Fire

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    Friend of mine took advantage of the Bangor Hydro program and ended up with a Mitsu unit . . . loves it. Relegated his wood pellet stove to only burning on the days when it is brutally cold.

    Sadly I am in Central Maine Power territory so no rebates . . . and hence . . . no heat pump.

    Was talking to a heating tech the other day who pretty much said the same as you . . . Mitsubishi is his preferred unit for installation. Says he has been installing heat pumps for close to 30 years -- said the newer tech has been great for working in cold weather areas.
  17. Highbeam

    Highbeam Minister of Fire

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    For those of you with two units, or experience with two. Can a single circuit feed both? I have a 30 amp 240 circuit stubbed out for this stype of thing that has plenty of power for two of them but I've not seen that type of install.

    I love that these things make full output into the single digits. As a kid, we had a traditional heat pump that would not do the job below 35 degrees.
  18. Dave A.

    Dave A. Minister of Fire

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    And you only get one inside unit. Big thing has to be put up high on the wall, can't hide it lower behind furniture. So it is kind of like a stove, leave doors open to get the heat around.
  19. peakbagger

    peakbagger Minister of Fire

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    I guess someone missed this There are flush mount wall and roof options for those who don't like the look of the standard wall mount unit.

    I do agree its like a space heater like a wood stove or pellet stove with the same limitations. Bangor Hydro was pushing it for elderly folks who typically spend most of their time in one part of the house during the day and then suggested the rst of the house could be kept at a lower overall temp
  20. Dave A.

    Dave A. Minister of Fire

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    I thought you were referring to the compressor outside, you said "roof". I'm talking about the inside unit. I realize there are recessed ceiling units, but I didn't think they were available with the higher efficiency hyperheat units that go down to 5F at full output (at least that's how it appeared to me in the brochure). I haven't seen any recessed wall units for inside, but that sounds possibly interesting (would assume mounted in a 16" stud bay)
  21. flyingcow

    flyingcow Minister of Fire

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    I think my big unit is on a 20 amp feed and the 12k unit is a 15 amp. If i was to do it again i would go with a split head unit. saves a little money on install. 5/600 bucks?
  22. RustyShackleford

    RustyShackleford Minister of Fire

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    Fujitsu is sold online as well - google some prices - but the parent company hates it and gives all sorts of dire warnings about the lack of warranty coverage for units bought online. Here's the amazing thing though: My installer, not really a pro, but a guy who does it on the side (he does much more high-powered but related work for his real job) checked with his local HVAC supplier, and the price they gave was almost identical to the online price. So obviously that's the way we went.
    You could just feed a couple of fused disconnects, or maybe a sub-panel.

    Believe it or not, I've basically not used the install we did about a year ago. The "encapsulation" of my crawlspace has made such a huge difference in my house's tightness that the BK is easily keeping me warm, without heroic effort. Seriously.

    For the Fujitsus at least, and for reasons I don't understand, the split head units do not have as good performance ratings (SEER and HSPF) as the single-head units like the RLS2 series.
    Last edited: Nov 30, 2013
  23. Soundchasm

    Soundchasm Minister of Fire

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    I got a Panasonic one ton unit installed in a "new construction" sunroom (very good r-factors in insulation and window glass packs). The old sunroom was damaged by falling firewood that thought it was a tree. The outside unit is really quiet. The air handler is quiet enough for me, too. I never stumbled across anything that lead me to believe there would be single digit heat, so I told my wife not to run it below 32 degrees, but maybe now I'll try that.

    You guys are all well-informed on details I only suspected. All I can add is that the copper flare seal for our unit was not done properly and everything leaked out. We'd find out in the spring that it wasn't cooling. The second year that happened a company replaced the Schrader(?) valve as a culprit. We'll see what happens this spring.

    I guess the 410 stuff is VERY high pressure for copper flare, and a "small" problem isn't possible.

    One technician told me there was no good way to measure the pressure to top it off. Said mine was designed to be empty and then weigh-in the coolant.

    Dayton Power and Light's rebate was only if a licensed company installed it. I think the installer was supposed to give the buyer a credit, but then DP&L issued a reimbursement and a 1099-misc to the installer. And the federal rebate for energy efficiency has a lifetime cap, and I went through that several years ago.

    There was a post earlier on about the HVAC air to air heat pumps kicking into auxiliary heat mode to make up a small differential. Mine does that and it's infuriating. It's really NOT an emergency to kick up one or two degrees. I have four daily time zones seven days a week, but that thing freaking out probably costs more than it saves...
  24. woodgeek

    woodgeek Minister of Fire

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    A different explanation....a Schraeder valve is just like the little valve stems you have on bike or car tires, right down to the little plastic cap. They are there to allow the tech to hook up gauges or pumps to test and refill the system (just like your tires). If the tech replaced that, it has nothing to do with the flare connections leaking (and they can handle much higher pressures than required for 410). I lost the whole 410 fill on my system but my tech admitted that he zapped the Schraeder when he soldered my lines. In your case, maybe your first tech did something stupid to get some dirt/grime in there during install (common, sadly), or its a manufacturing defect. ??
  25. RustyShackleford

    RustyShackleford Minister of Fire

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    Lordy, I am SO lucky. The guy who helps me with HVAC does it as a sideline to his main job - maintaining cryogenic systems at a major research university.

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