Click here to Find a Contractor in your area.
Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit

Unico or Spacepak?

Adding AC soon to a hydronic-ly heated house.

If we go the hi-velocity route versus conventional...what are my deciding factors Unico versus SpacePak?


  • Steve Minnich
    Steve Minnich Member Posts: 2,662
    You can’t go wrong with either. They’re both very good and I’ve installed many of each over the years. I’d suggest going with the one your contractor is most comfortable with.
    Steve Minnich
    Minnich Hydronic Consulting & Design, LLC
    [email protected]
  • mikeg2015
    mikeg2015 Member Posts: 1,183
    edited November 2019
    Property design and installation is EVERYTHING on these. They are not very forgiving like conventional ducted system. Done wrong, they are noisy, leaky power hogs. Hydronic will be a little more forgiving, but need to make sure water temps, design flow rates, airflow rates are all checked so you’ll have enough capacity.

    Most of these have water/air temp limits since the coil is before the blower motor.

    I had a Unico installed at my house poorly before I was in the trades. There’s leaks, it’s noisy and power use is only a little better than when I was running 4 window units upstairs. 3 ton outdoor unit and delivered capacity is probably not better than a 2 ton conventional... though it dehumidifies better, but not that much better since all the air leaks push humidity from the attic into the house anyway.

    Bottom line for me, old houses are quiet with thick walls, and my conventional system downstairs is silent, and my Unico upstairs is only silent below 60% of high stage cooling airflow speed. They already extended the take offs which quieted it down some. It just needed a LOT more outlets.

    Spacepack seem more common and easier to get parts. Took over a week to get a failed TXV replaced right after it was installed.

    1) Use all metal ductwork for the plenum, and lots of mastic, R8 insulation sealed completely.
    2) err toward using more outlets to reduce noise.
    3) Verify actual heating capacity using mfg charts.
  • clammy
    clammy Member Posts: 2,661
    Unico perimeter loop 8 outlets per ton and use spiral duct and fittings all joints sealed and externally wrapped w r 8 fiberglass insulation . Seperate returns for 2 story homes and always a space guard hepa filter just a few basics to look for including a getting better then the builders grade Outdoor unit .they are not a inexpensive system but in any case I ve used them i there was no other ways aside from massive renovation work . I come across a lot which are installed below sub par they work there loud ,I would say I see more bad spakepak system then unico and more space pack then unico installs who knows why there both handled locally .peace and good luck clammy
    R.A. Calmbacher L.L.C. HVAC
    NJ Master HVAC Lic.
    Mahwah, NJ
    Specializing in steam and hydronic heating
  • John Mills_5
    John Mills_5 Member Posts: 935
    Unico support is amazing. I've called Space Pak and they didn't answer. Probably not a biggie for the homeowner but something to know.
  • clutterbug
    clutterbug Member Posts: 14
    I'm very late to this discussion, but I have had a unico hi velocity system in my house for approximately 10 to 12 years, maybe more I have to look it up.
    The supply lines completely rotted and Unico's response was "it's your fault you had moisture"
    That's utter fabrication on their part. No one came out to look at it. So I would have to say based on my direct experience with their customer service (neither did they answer any emails of mine) ... they customer service and standing behind their products is not good at all!
  • unclejohn
    unclejohn Member Posts: 1,736
    Not only did I get right through to space pac, the rep said he would be in DC in a few days and meet me on the job. That was a while ago. So it is what it is.
  • GW
    GW Member Posts: 4,248
    I did Unico wayyyy back when it was 5 outlets per ton. Yep you could hear it 😀
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • mikeg2015
    mikeg2015 Member Posts: 1,183
    I find it has to be running under 20CFM/outlet to be as silent like my conventionally ducted downstairs system. Heck, it’s still louder even then. :)