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High Velocity Systems (The Youngster)

Find an installer who has been to Unico's Advanced Certified Product training course. The training shows you the right way to install hi velocity systems ie. more runs equals less noise. Call Unico and they will help find someone 800-527-0896.


  • Josh M.
    Josh M. Member Posts: 360

    Our AC contractor tells me we need to install a high velocity system in a $10+ Million house were doing. Gulp! Are these systems noisy? Have heard all the arguments from the reps, but I want opinions! Even though I'm only doing the Hydronics, I'm still responsible for the AC..
  • Jim Pompetti
    Jim Pompetti Member Posts: 552

    Just follow the direction to the T Add a few extra outlet you'll be find .They do not make any more noise the a conventional system
  • Jed_2
    Jed_2 Member Posts: 781

    No, Josh, they are not noisy, IF, you follow the design rules for HV systems. If this is H/C HV, I suggest a 4-pipe chilled water system, with load diversity strategy. This can be accomplished with a detailed Manual J analysis and careful zoning. System (each air handler zone) air flow balance to the outlets is critical for even distribution. Chilled water systems are "hydronic freindly" and require minimum invasion to the structure, no line sets to calculate charge, and utilize zone valves. Cooling solution does require Glycol(no gas here, it's all in the the chiller) at a minimum of 10%, depending on geographical location.

    Check out Multi Aqua; quality equipment.

    Space Pak is another very good product.

    good luck

  • tim smith
    tim smith Member Posts: 2,752
    High V system

    Josh, I don't install them but over the years have seen quite a few poorly installed ones with many short comings due to that. I would be very careful w/ who is proposing this and that they have done several. Then check w/ the sites that they have installed and see how happy the clients are with the systems. I think their is a place for these systems in remodels and tight construction areas but watch carefully. Tim
  • Boilerpro_5
    Boilerpro_5 Member Posts: 407
    I've been looking closely at these systems....

    because I plan on starting in the High Efficiency A/C field. They are not any noisier than conventional forced air systems (which to me are rather noisy).
    I would look closely at the Energy Saving Products line at hi-velocity.com. Then take a look at the ari directory to see thier efficiencies when matched up to your choice of outdoor coils. I made a very interesting discovery here. While Unico and Space Pak were fighting against the new higher SEER standard because thier products could not meet the new standard (and they recieved an exemption), ESP appeared to be absent from that argument. A look at the SEER ratings of thier products will tell you why. Typically, thier units, when tied to a manufacturer's outdoor unit, will meet or exceed the efficiency rating of the manufacturer's most efficient combination. This appears to occur completely up and down the product line. So while Unico and Space Pak can bearly get over 10 SEER with any outdoor matchup, the ESP units hit over 21 SEER at the top end and typically run near 14 SEER on a 13 SEER outdoor unit. I suspect that alot has to do with the fact that ESP uses an ECM type blower, while the others still appear to use old fashioned energy hogs.

    SEER isn't everything and certainly does not tell the whole story, but I find the huge diffences in SEER ratings eye opening.
    I will probably be installing ESP units for my first installs. It appears they require a little more custom work than the others, but a likely 30% to 100% improvement in efficiency is significant in my eyes as we enter a period of rapdily rising energy costs. Just what to see what happens when the CO2 emission regulations begin to kick in.....YIKES!

    I may be missing something here since I'm a newbie to the field, so I would definitely take that inot consideration.

    BTW have you looked at Ductless Split units? They may work out well for you.


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  • tom_49
    tom_49 Member Posts: 269


    We have installed a bunch of Unico systems. They are a little louder than a conventional system w/ standard blower motor. To make them the quietest they can be, you need to use all 12' of sound attenuator tubing, dont cut them in half to save $$. Also add a couple extra outlets to reduce velocity ( and noise ).

    If you really want a quiet system, go with the Carrier Infinity. We installed one this week( and have about 200 more installed). While standing with the HO in the attic ( 2' from a/h )going over everything,
    she asked " when does it sound like when its running", I said " it is running". She was very happy to say the least. No other a/c system compares to these things.

    Good luck, Tom

  • Designed and installed properly, noise is not an issue.

    Key things to remember:

    A "standard" run is 10 feet. These count as one outlet. The longer the run, the more restriction and the less air--thus you compute them as a portion of a "standard" outlet--say 0.8 Unico in particular has exceptional instructions.

    At least 3' of "sound attenuating" duct must be used at the end of each run. "Standard" 10' runs are usually run using only the "sound attenuating" duct.

    Be truly obsessive regarding duct sealing! At the velocities involved, little leaks can make obnoxious noises. Follow installation instruction to the letter! The "sound attenuating" duct has a scrim core that is somewhat air permeable. Seal any "accidents" in the outer foil covering with good aluminum "duct tape".

    If at all possible use a "loop system" for the supply plenum. A few feet after the air handler (NO outlets here), you install a full-sized tee and then install the plenum in a loop. This ensures equal pressure at all branch connections. "Straight" or "branched" plenums require very careful engineering.
  • Couple of things

    They are quiet as long as you follow the instructions. Use the advanced control board so the blower will have a slow start. We always use all 12' of the attenuator tubing and add extra outlets where we can
  • John Koll_3
    John Koll_3 Member Posts: 9
    Hi-V mix/match SEER

    Boilerpro, can you supply an ARI reference number as an example?
  • Josh M.
    Josh M. Member Posts: 360

    Thanks all! I will heed your advice!

    That is a big weight off!

  • Tombig_2
    Tombig_2 Member Posts: 231

    One more thing. Have your guy design a return duct system besides the recommended ten ft. or so to a central return. Oversize the return ducts and grilles. Insulate the inside of return ducts (if rectangular) to minimize sound transmission. When designing returns lineal distance from the air handler is your friend.

    Place the supplies where they'll have a clear shot to the floor if possible (Unico recommended). An obstruction (try it with your hand) will create an air movement noise in a quiet room.

    Check into Unico's chiller unit and pneumatic zoning package. I haven't installed one yet but the technology is impressive.

    Tom Goebig
  • Josh M.
    Josh M. Member Posts: 360

    Thanks! I will!
This discussion has been closed.