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Indoor Pool HVAC

Customer has a basement indoor pool - area 25x35. They currently have an R22 based system by PoolComPak. They want to take that out and possibly install a ductless system - like Fujitsu. They are spending about $800/month in electric to use that unit. I called Fujitsu and of course they don't recommend that. My question is, will a ductless unit dehumidify as needed and heat & cool?


  • Matt_67
    Matt_67 Member Posts: 266
    be careful

    Be careful - ductless mini splits have a dumidification mode but they have no ability to reheat like a pool dehumidification unit does. Pool dehumidifiers are expensive to run - but if they don't like the $800 / month to run it they surely won't like the $xxx,xxx.xx in damage not having a proper dehumidification / ventilation system can cause. Everything matters with these - pool temperature, air temperature, air pressures relative to living spaces, etc and improper systems can lead to massive mold and rot issues in the home.
  • Pipe
    Pipe Member Posts: 14

    This is going to sound crazy, how about a dual system. One set to dry mode and the other for automatic temperature control?
  • Matt_67
    Matt_67 Member Posts: 266
    i wouldn't

    That doesn't sound like a cheaper method to me - with the current unit the heat you remove from the evaporator coil ends up either in the pool water or back in the room depending on what unit you have. With the mini split you would be running two compressors to do the same work. Do you know how they are running the system right now? Are they running the room temperature higher than the pool water temperature? Do they cover the pool when not in use? Those things make a huge difference in the amount of energy used.
  • Pipe
    Pipe Member Posts: 14
    The pool

    Is heated with a gas fired pool heater. The pool com pak is a split system with outdoor condenser. They cover the pool when it's not in use. Temp of pool is kept at 86 degrees.
  • Matt_67
    Matt_67 Member Posts: 266
    room temp

    What temp do they keep the room at? What area of the country are you in?
  • Pipe
    Pipe Member Posts: 14
    They keep

    The temp inside at 76-78. Long Island.
  • Jack
    Jack Member Posts: 1,046
    "I called the manuf...

    And they don't recommend that application" the problem is they are simply not designed to operate and survive that chemical content in the air. I'd strongly suggest you heed their warnings. They won't last.
  • Matt_67
    Matt_67 Member Posts: 266
    low air temp

    That's part of the reason for the energy usage - typically dehumidifers are sized with the expectation that the air temp will be something like 2 degrees warmer than the pool water to control the evaporation rate.  I would guess the unit is running all the time.  As far as the split condenser - that is an option to provide cooling should the room be too hot.  There is also a reheat coil in the unit itself.  If the dehumidifier hasn't been serviced regularly it would be a good idea to make sure all the coils are clean and the refrigeration system is properly charged and operating correctly.  I probably can't help you much more but to say be careful - we dotted all the i's and crossed the t's and still had a very unpleasant situation with a similar residential indoor pool that was not being run as designed.
  • Techman
    Techman Member Posts: 2,144

    Can you use the self contained unit the recovers/recycles the btu's back into the air/water?
  • TonyS
    TonyS Member Posts: 849
    Daiken Quaternity

    it has the ability to dehumidify and heat simultaneously.

  • hheaddon
    hheaddon Member Posts: 10
    pool hvac

    There is plenty of info on the web in regards to indoor pool rooms and or spas.  Not keeping the temps as required will raise the operating costs, degrade the equipment's life span and more important, ruin the enclosure the pool or spa is in. I have worked on a number of systems in residential  applications, where trying to save money  or not keeping the the equipment  maintained or at design settings ruined the enclosure's.
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