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minisplit ductless heat pump

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

  1. Highbeam

    Highbeam Minister of Fire

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    Turns out that my utility company will give me a 1200$ rebate for installing one of these. They are ugly but I can see no cheaper way to heat my home when wood heat is unavailable.

    So in general, how low from a flat ceiling must the indoor unit set? Higher is better since I want to put something under it like a piece of furniture to try and minimize the visual impact. Is there also a limit to how close something like furniure can be to the bottom?

    The indoor unit will be on an interior 2x4 wall. Does the lineset fit/fold up inside the 3.5" cavity or must it poke into the room behind? Do you drill holes into the top of the wall and pass the lineset into the attic? Finally, does the lineset exit the indoor unit from the left or right and is this switchable?

    I'll be installing a single 2 ton unit for whole house heating since buying a handful of smaller units seems significantly more complicated and expensive. The smaller units are typically more efficient but only slightly. I am finding that the Fujitsu units (my preference) are rated for heat down to 0 degrees which means that I won't need a backup to this "primary" heat and I can remove some of those wall heaters.

    They are ugly like a blaze king but the minisplits are superior performers.

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  2. begreen

    begreen Mooderator Staff Member

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    The Fujitsu 2 ton unit is a good one. Mitsubishi Hyper Heat H2i inverter units are rated to work below 0. They're worth researching also. You can mount the head units high enough to clear furniture. Most of the units I have seen are at about the 5-6' level. In warmer climates they are often put at just below ceiling level for better cooling performance. Mitsubishi also makes a floor cabinet head unit if that is preferable.

    One head unit is rarely enough for even house heat. I would plan on at least 2 head units. Get multiple estimates from experienced professional installers that knows these units and have installed many. You might be surprised at the range in quotes. Get references and take the time to look at a couple of each bidder's installations. Workmanship can vary a lot from company to company.
  3. Highbeam

    Highbeam Minister of Fire

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    I don't intend to hire this out. That never works as well as doing it myself and since this tech is so new, there are no experienced techs anyway. The professional will come to do the final charge and hookup though and to check for mistakes. I have a woodstove that heats the whole home very well so a mini in the same room should perform similarly.

    There are a few alternative indoor units but the price gets very high very fast so a standard wall unit is the best way to go currently.

    A simple single unit on an interior wall. I can always add another. They are significantly cheaper purchased separately than as a multihead system.
  4. begreen

    begreen Mooderator Staff Member

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    Will PSE cover a self install? As far as experience, I would ask. Locally we have a fellow that has installed at least a dozen of these units a year since about 2008, even more recently. It doesn't cost anything to get an estimate and could be a learning experience. After a few estimates you should have a better idea of whether your plan will work, or not. Ask how long they have been installing these systems. The outdoor unit should be designed for multihead from the beginning. Do it right the first time and you won't need to add another complete second system. If you do self install be extra careful about keeping the lines clean, dry and kink free. I would not run them in a wall for risk of condensation drips causing rot. They make finishing covers to neaten the insulated lines.
  5. velvetfoot

    velvetfoot Minister of Fire

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    Is there an upstairs? Having A/C as well as heat would be nice.
  6. Highbeam

    Highbeam Minister of Fire

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    Yes, PSE covers self install. They actually identify how to get the refund if you self install. I was surprised at this since they seem to like to have some professional verfication that you actually installed the equipment. No mention of a permit either.

    The multiheads are very non-cost-effective. It is cheaper to install several single heads and when done this way, if there is a failure of one of the units the other ones will remain in service. Even if the price is the same it is wise to install several small systems. Efficiency is higher as well. I'll look into the Mitsubishi units too, haven't researched them yet.

    I do like your idea of getting some quotes. Nothing to lose. I am too particular about things being done properly and cleanly to have a tech do it unless I can be certain of their skill.

    Single story house that has never had or really needed A/C but all of these minisplits that provide heat will also provide cooling.

    I would only run the lines within the wall between the unit and the crawlspace or the attic and then exposed all the way to the outdoor unit. Do the lines exit from the left or right side of the indoor unit?
  7. velvetfoot

    velvetfoot Minister of Fire

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    I'll be interested in how your project turns out.
  8. Retired Guy

    Retired Guy Feeling the Heat

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  9. Highbeam

    Highbeam Minister of Fire

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    After reading a few installation manuals I am finding that these things are really meant to be installed on exterior walls with the linesets immediately pushed to the exterior. What an ugly concept to have the lines scabbed onto the outside of your home even if they are "covered" with plastic gutter looking channels. The indoor units can be mounted within 3-4" of the ceiling and only 8" from the sidewall so you can tuck these into tight spots. It also looks like the standard lineset from the indoor unit exits to the right when you are standing in front of it but with effort can be moved to other locations.

    Goes to show you, this technology is very green, and young. Almost nobody on this site has even seen one installed.

    Best thing for me now is to have a contractor come out for an estimate which is really when I pick his brain about these things.
  10. Retired Guy

    Retired Guy Feeling the Heat

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    Neighbor put one in to an unheated room addition that he used to close off in the winter. Installer said he was ok for heat down to 5 degrees F.
  11. woodgeek

    woodgeek Minister of Fire

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    Highbeam, did you calculate how low a temp a 2-ton unit will carry you?
  12. RustyShackleford

    RustyShackleford Minister of Fire

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    I agree with you about the manuals, but my guy says interior wall is fine and yes the lineset easily fits in a 2x4 stud wall (we're midway through installation). You also need a condensate drain and the (for my unit, at least) stranded 4-conductor plus ground to connect the indoor unit (which is powered and controlled from the outdoor unit).

    My guy also believes Fujitsu (which I'm using) and one other (which I can't recall, Mitsubishi maybe) are the best. I'm adding a 1-ton (aka. 12Kbtu/hr) one for a small addition, in lieu of extending the ductwork from my old inefficient dual-fuel heat-pump system. I consider it a down payment on replacing the whole house's HVAC, and in mild weather I'm hoping it can mostly handle the whole house, with a transfer duct to cycle air from the rest of the house through the addition room. My data says the single units are a LOT more efficient than the multi-zoners, so I'll be tempted to go with a couple of singles when the time comes. But who knows what the HVAC landscape will look like then.
  13. tbuff

    tbuff Feeling the Heat

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    There are evap unit options out that aren't as "box on the wall" type. Also, if doing the install yourself, and if not experienced HVAC tech, I'd recommend trying to find out which manufacturers use a pre-charged compression fitting lineset. May be a little more money, but saves some labor. What SEER are they telling you that you need to install to meet the rebate?
  14. RustyShackleford

    RustyShackleford Minister of Fire

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    My Fujitsu (12 RLS2 series) comes with the outdoor unit precharged, so when you connect the lineset, it breaks some sort of seal and charges the whole system. At least I think that's what my guy said. If the lineset is over a certain length, you have to add refrigerant (but it's more than 30ft IIRC).
  15. tbuff

    tbuff Feeling the Heat

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    Is it R-22 or R-410a?
  16. velvetfoot

    velvetfoot Minister of Fire

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    What's the diff?
  17. tbuff

    tbuff Feeling the Heat

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    Different refrigerant or as most call it "freon" used. There was a big push for 410a a few years ago to the point where they stopped producing 22 equipment. Then companies kind of found a loop hole, if you make the equipment but just don't ship it or sell it with the refrigerant in it, its ok. I personally like R22, easier to work with a little more forgiving so to speak when it comes to pressures and oils used etc...
  18. Highbeam

    Highbeam Minister of Fire

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    The required seer was so easy to meet that any mainstream brand would do it, reminds me of the woodstove efficiency requirements. It does have to be an inverter unit. The power company also has a sizing guide on their site so you can enter your home's information and it spits out the required tonnage. It said I need a 2 ton unit to carry the house into the low teens. The better brands of mini split claim "full" output well into the single digits.I haven't seen any of these newer units using anything but r410a which is fine with me.

    Rusty, please post up a thread with installation photos for us all.
  19. tbuff

    tbuff Feeling the Heat

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    Does the calculations on their site account for window quality/quantity, insulation, basement/crawl/slab, etc? If so, it definitely something you can handle with patience and a little bit of guidance. Be very careful with anything with 410a, were talking a normal operating hp line of around 500 as opposed to 22 with it around 200. Good luck and feel free to pm me if you are stumped.
  20. Highbeam

    Highbeam Minister of Fire

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    Thanks tom. I'm a ways from buying right now. The calc required me to input all the things you list. If anything I'd say a bit more btu would be needed but that is fine.
  21. Highbeam

    Highbeam Minister of Fire

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    Piece of cake to put these things on a 2x4 wall. This is an LG on an exterior wall but he wanted to hide the lineset within the 2x4 wall. Condensate drainage will always be an issue and a pump will be needed for my interior wall locations.

    Stupid system won't let me upload the photo. I'll try some other methods. Apparently, Hearth doesn't like bmp files. Anyway....

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  22. pen

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

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    Started using the Mitsu Hyperheat unit in the beginning of July and love the thing. Sips electric and was cranking out heat like crazy when I tested it below 0 a few weeks back. Unit is rated to keep putting out 80% of it's heat down to -13F. Mine is rated 18k btu cooling, and about 22k heating. I believe this is the same thing http://www.homeenergyproducts.net/files/18k_hyper_heat.pdf

    Really impressed so far with one exception. The automatic fan doesn't run fast enough and temps drop below the set level for heating, and above the set level for cooling, if I keep it in auto.

    pen
  23. begreen

    begreen Mooderator Staff Member

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    Our 3 ton system is R410. Not a big deal according to our installer. It's a full split American Standard system that has been running fine for 6 yrs. now. I wanted to install a mini-split system back then but they were too new to our area and hard to get. However I did get my installer investigating them and he started installing them a couple years later. Now that is almost all he installs.

    Pen, our installer started using the Mitusbishi HyperHeat units about a year ago locally. They are awesome in our climate. Good to hear that yours is working out well for you. Mitsubishi, Fujitsu and Daikin are the most common mini-split units installed here.
    pen likes this.
  24. peakbagger

    peakbagger Minister of Fire

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    There are systems that are represented to be self installable but good luck if they ever stop running and you need waranty service. Most sets ship with the outside unit precharged so when you hook up the line set and open a valve they will usually work as long as the line set length isnt longer than their specs. Unfortunately this gets some moisture into the refrigerant unless you first pump down the line set with a vacuum pump. The other reason for pumping the line set down is that you can find slow leaks. The unit may run for a short time with a slow leak but not for long.
    pen likes this.
  25. Highbeam

    Highbeam Minister of Fire

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    Either way, a monkey will install it and an experienced monkey will check and charge.
    Dave A. likes this.

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