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  1. #1
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    Daikon VS Mitsubishi City Multi

    I am a general contractor and am building a 5-6 zone 2900 sq ft residence in NC. Under consideration is a 4 ton Daikon with factory start up versus a 4 ton City Multi S series. There is a FROG which will have its own separate system.

    1) Is one brand clearly better?
    2) Is one system better at addressing the make up fresh air as I have a sealed crawlspace?
    3) Is one system better at addressing allergy concerns?

    NO ONE HAS A SUBSTANTIVE ANSWER.

    LET ME ADD MORE INFORMATION:
    The house is shaped like a U with the bedrooms on one side and living room covering the entire other side. In the middle is the kitchen. And in front of the kitchen with a southern exposure is a sunroom. From the living room a set of stairs go up to a landing with an office that overlooks the living room. At the second stair landing is a catwalk that goes into the master bedroom. The master is above the kitchen.

    Ducts to the bedrooms and possibly to the kitchen zone. Concealed ceiling unit in the sunroom and living room. Two floor mounted hidden units at office: one blowing out over dining room bellow and the other ventilated the office which has a 17' ceiling that slope down to 13' on the other side of the living room. The other side of the living room is 40 feet away. In the master, a hidden concealed fan will blow into the master and some flow will be directed back to the bathroom. The Daikon contractor preferred to drop the ceiling here and intall a fan coil with venting to the bedroom and to the bathroom.


    Thank you in advance
    Last edited by gonzoactive; 06-09-2009 at 09:36 PM. Reason: I had some responders who say more info needed.

  2. #2
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    Just go with the cheaper one , why stop now?
    You sure are cocky for a starving pilgrim.

  3. #3
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    Quote Originally Posted by zachhvac View Post
    Just go with the cheaper one , why stop now?
    I was shocked when I first read this reply....on the second read through I realized that it is justified.

  4. #4
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    These are mini-splits... if IAQ is an issue, you should be usign a conventional split system.

    Minisplits make sense in urban apartment building and palces where space si a premium for ductwork, or retrofits where ductwork isn't psosible.

    Why would you want to use a mini-split for new construction??? Installing a properly dsigen split system with zone control can achieve the same function, with better IAQ since you can add proper whole home ventilation.

    Honestly, I'm not sure why a 2900 sq. ft residence really needs 5-6 zones. If they are that particual about IAQ and comfort, why would they want mini-splits? Maybe 3 or 4. But the sky's the limit with zone control.


    Don't get me wrong minisplits ahve their place in certain applications. But new construction on a single family residential building???

  5. #5
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    Quote Originally Posted by zachhvac View Post
    Just go with the cheaper one , why stop now?

    I was thinking a PTAC in each zone... maybe some baseboard heaters as well for those really cold NC winter nights.

    OTOH... to be fair, the concept isn't bad. I like the picture Dainkin shows. It's a interesting installation. and paritally ducted. I suppose you could still add a independant central ventilation system of some sort that removes air from the bathrooms and kitchen and supplies it to the a common space. You could probably even use it together with a whole house HEPA unit.

    But ultimately if I was the HO... if I'm dropping $300k+ for a new 2900 sqft home, I'd want a conventional HVAC system. The extra $X,XXX will be worth it. Shave off 200 sq-ft if their budget is tight.

  6. #6
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    Quote Originally Posted by tech45 View Post
    I was shocked when I first read this reply....on the second read through I realized that it is justified.
    rotflmao
    You sure are cocky for a starving pilgrim.

  7. #7
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    Quote Originally Posted by motoguy128 View Post
    These are mini-splits... if IAQ is an issue, you should be usign a conventional split system.

    Minisplits make sense in urban apartment building and palces where space si a premium for ductwork, or retrofits where ductwork isn't psosible.

    Why would you want to use a mini-split for new construction??? Installing a properly dsigen split system with zone control can achieve the same function, with better IAQ since you can add proper whole home ventilation.

    Honestly, I'm not sure why a 2900 sq. ft residence really needs 5-6 zones. If they are that particual about IAQ and comfort, why would they want mini-splits? Maybe 3 or 4. But the sky's the limit with zone control.


    Don't get me wrong minisplits ahve their place in certain applications. But new construction on a single family residential building???

    These systems can be ductless or ducted depending on the model. He doesn't give us enough information to say for sure what he is doing, but it will probably come down to which is cheaper..

  8. #8
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    Quote Originally Posted by tech45 View Post
    I was shocked when I first read this reply....on the second read through I realized that it is justified.
    took me two reads too

  9. #9
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    Where does the OP say he is looking cheap? Doesn't seem to me that either one would be. If he wanted cheap, a single zone forced air would be the choice. Does anybody have a comment to Daikin vs Mitsu?

  10. #10
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    Quote Originally Posted by BaldLoonie View Post
    Where does the OP say he is looking cheap? Doesn't seem to me that either one would be. If he wanted cheap, a single zone forced air would be the choice. Does anybody have a comment to Daikin vs Mitsu?
    I have a single 4 ton Daikin VRV system with four ducted zones (and no, motoguy128, these are not mini-splits). I am quite happy with the system and the support Daikin provided during the design and installation phases.

    To the OP - you should make sure they both have similar levels of heat output at design conditions. The cooling and heat output will be determined by the number and size of indoor units that are connected to the one outdoor unit. If you have not had each manufacturer run your proposed system through their software you may want to do that. Daikin can tell you exactly what it will cost to operate your system in an average year. Since November, when my system was installed, my energy usage has been very, very close to what they projected it would be.

    Everything I heard about Mitsu has been positive - the system just may not be as energy efficient as the Daikin. Depending on when the install will actually done, Daikin's new VRV-S III may be available. It is more energy efficient than the current model.

    They both can handle HRVs and I would suggest using third party media filters for the ducted units. The air filter is to protect the equipment not the occupants of the home.

  11. #11
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    Quote Originally Posted by BaldLoonie View Post
    Where does the OP say he is looking cheap? Doesn't seem to me that either one would be. If he wanted cheap, a single zone forced air would be the choice. Does anybody have a comment to Daikin vs Mitsu?
    Heeeees aaaaaa General Contractor?
    You sure are cocky for a starving pilgrim.

  12. #12
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    I saw that they were ducted... but for IAQ, it doens't look like you cold have a central air handler with a media filter, humidifier, dehumidifier, or HRV/ERV. the "ducted" from the picture i saw amounted to 1 indoor coil unit, being used to heat/cool two rooms. I still woudn't call that a central duct systme or sonsider it equivalent.

    But like some commerical systems, I suppose the VRV's could be used in a central air handling system. that would give you the benefit of IAQ accessories as well as having maximum air circulation at all times no matter the call for heat or cool.

    So I may stand corrected. The examples on the website didn't illustrate very well the diffrent applications.

  13. #13
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    Quote Originally Posted by motoguy128 View Post
    I saw that they were ducted... but for IAQ, it doens't look like you cold have a central air handler with a media filter, humidifier, dehumidifier, or HRV/ERV. the "ducted" from the picture i saw amounted to 1 indoor coil unit, being used to heat/cool two rooms. I still woudn't call that a central duct systme or sonsider it equivalent.

    But like some commerical systems, I suppose the VRV's could be used in a central air handling system. that would give you the benefit of IAQ accessories as well as having maximum air circulation at all times no matter the call for heat or cool.

    So I may stand corrected. The examples on the website didn't illustrate very well the diffrent applications.
    Ducted units range from 6,000 BTU to 4 tons. If you wanted a single air handler that is an option. But, the fact that up to eight indoor units (ducted, ductless or a combination of both) can be connected to a single outdoor unit allows for you to create zones that pretty much stand on their own. Individual indoor units can be set to their own temps and set back schedules (I don't think set backs are a good idea with heat pumps) separate from the rest or even turned off. Very hard to do that with a conventional ducted zone system.

    Each indoor has a 2,000 step electronic expansion valve that will allow it to operate as low as 10% of its nominally rated output. The ducted units do allow for connection of an HRV, humidifier, and installing media filters is no different than with conventional A/Hs - bigger is always better. Two of my units have media filters installed at the A/H and two have media filters at the return grills. Because of the broad modulation capability of both the indoor units and the outdoor unit, stand alone de-humidification is not really needed because of extend run times.

    Here is a real world benefit of zoning in this way. My first floor faces east/west and the zones are set that way too. The back part that faces west gets a heavy load during summer afternoons while the east part of the first floor almost never gets warm enough to call for cooling. I set west zone to maintain temp and the east zone in the Dry mode to keep that area from getting a little muggy. With my old conventional system the east part was way over cooled during the summer. Another real world is the heat output. My 4 ton system produces over 40,000 BTUs at 10* - show me a conventional HP that will come anywhere close to that.

    I hope this has helped.

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