Klingspor's Woodworking Shop (Festool) Ad #2

Special Events in the next 30 days

Page 1 of 2 1 2 LastLast
Results 1 to 15 of 21
  1. #1
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    419
    Visit Freq
    5.62 visits/week
    Threads
    98
    Classifieds
    0

    Mini-Split, Dehumidifier ??

    Just got a digital temp and humidity gauge for the shop. My Pioneer Mini-Split unit has a 'DRY' setting to dehumidify, but when I run it on that mode it will drop the temp into the low 60's! I haven't tried it often, once this winter and then again last week when the humidity seemed really high inside. I went out the next morning and the walk thru door was condensing water everywhere on the outside because it had cooled so much inside.

    Is that normal for the dry setting? Does the temp gauge setting not generally work when on the dry mode?

    Just curious. Humidity is running in the high 60's inside the shop. Building is very well insulated. I might go in/out 1-2x's a day, so shouldn't be letting in a lot of humidity.

    Just curious how others work. I know mini splits aren't known for their humidity control.
    Last edited by DSWalker; 06-03-2018 at 07:25 PM.

  2. #2
    Senior User
    DQ
    redknife's Avatar
    Nickname
    Chris
    Join Date
    May 2013
    Location
    Mocksville, NC
    Posts
    997
    Visit Freq
    6.73 visits/week
    Threads
    83
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    My shop mini-split didn’t “over-cool” on the dehumidify mode. The temp stayed as set. In theory it slowed down the cooling to extract more moisture (per hvac guys). That said, dehumidify didn’t seem to make a practical difference in RH vs cooling mode. I ran a separate dehumidifier.

  3. #3
    User
    Nickname
    Bruce
    Join Date
    Nov 2005
    Location
    Apex, NC
    Posts
    6,008
    Visit Freq
    5.77 visits/week
    Threads
    994
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    In the early AM, dew point was most likely higher than shop temperature, thus condensation. Several days this past week, dew points have been over 70. As soon as sun comes up, temp rises and dew point lowers, thus no condensation during the day. Condensation is why you can't paint bridges at night.

  4. #4
    Senior User
    Nickname
    George
    Join Date
    Jan 2017
    Location
    Tellico Plains, TN
    Posts
    155
    Visit Freq
    6.96 visits/week
    Threads
    1
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    What they are attempting to do is lower the air temp below the dew point.
    True dehumidification will actually use both heat and refrigeration.
    Industry standard for comfort and humidity is generally 72 degrees and 40-60 percent relative humidity.

  5. #5
    Board of Directors
    Treasurer
    Corporate Member
    DQ
    KenOfCary's Avatar
    Nickname
    Ken
    Join Date
    Mar 2010
    Location
    Floyd, VA
    Posts
    7,798
    Visit Freq
    6.81 visits/week
    Threads
    520
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    I don't have a mini split (but would like to install one eventually for the heat) but my basement shop has a separate dehumidifier. It has started coming on the last month or so - I keep it set at 50 and it does a good job keeping the humidity at or close to that. If I have to open the garage doors for any length of time it works a lot harder.
    I don't believe in Astrology. I'm a Sagittarius and we're skeptical.

    "May the grain be with you" - Roy Underhill

  6. #6
    Corporate Member
    DQ
    Tarhead's Avatar
    Nickname
    Mark
    Join Date
    Nov 2005
    Location
    Concord, NC
    Posts
    3,865
    Visit Freq
    6.38 visits/week
    Threads
    348
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    Dehumidifiers work by blowing room air over cold coils. Water vapor condenses into liquid water and it drips to a collector or in your case a drain. Most inside/portable units produce more net heat to compress the refrigerant and operate the fan than they produce cold air. With a mini split or regular permanent A/C units most of the heat produced is vented to the outside and the resulting cold dry air is blown inside.

  7. #7
    Senior User
    DQ
    redknife's Avatar
    Nickname
    Chris
    Join Date
    May 2013
    Location
    Mocksville, NC
    Posts
    997
    Visit Freq
    6.73 visits/week
    Threads
    83
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    David, are you able to get your eyes on the manal? I will say that the American Standard customer manual was shorter than light switch instructions. Installer? (Doesn’t sound right to go that far off temp setting)

  8. #8
    Senior User
    Nickname
    Jeff
    Join Date
    Mar 2008
    Location
    Rougemont, NC
    Posts
    7,369
    Visit Freq
    6.92 visits/week
    Threads
    635
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    No specific answers to your questions but this calculator may help. Play around with any 2 of the 3 sliders to see the effect on the 3rd one.

    We've had dew points in the 70-74 degree range over the last 2 weeks so it's been really soggy.

    http://www.dpcalc.org

    What does the mini-split do in just the AC mode instead of DRY?

  9. #9
    User
    Nickname
    Michael
    Join Date
    Nov 2005
    Location
    Winterville, NC
    Posts
    354
    Visit Freq
    2.08 visits/week
    Threads
    18
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    I only have a window AC unit in my shop. I just run it while in the shop; maybe start an hour before to cool down the interior before working inside. My humidity gauge shows a noticeable drop in % after running for a while. I am thinking it is just the AC function that is
    moving the humidity down.

  10. #10
    Senior User
    DQ
    Skymaster's Avatar
    Nickname
    Jack (78)
    Join Date
    Aug 2009
    Location
    Zebulon, NC
    Posts
    1,847
    Visit Freq
    6.73 visits/week
    Threads
    43
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    A/c in normal function cool and DE HUMIDIFYS drier air feels cooler at room temp than humid. every a/c has a drain because of that function

  11. #11
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    419
    Visit Freq
    5.62 visits/week
    Threads
    98
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    Quote Originally Posted by Jeff View Post

    What does the mini-split do in just the AC mode instead of DRY?
    It is cooling w/o any issue. Just had a high humidity level. When I use the DRY function is will freeze you out!

    I found my owners manual this morning and am going to reread, and then possibly reach out the MFG. I really don't think it should be dropping the temp so low when in the dry mode.

    Thanks for all the comments and information.

  12. #12
    Senior User
    Nickname
    Jeff
    Join Date
    Mar 2008
    Location
    Rougemont, NC
    Posts
    7,369
    Visit Freq
    6.92 visits/week
    Threads
    635
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    It is cooling w/o any issue. Just had a high humidity level. When I use the DRY function is will freeze you out!
    Did you measure the humidity level while it was just in the cooling mode? I think that several responses here suggest that the cooling mode should be adequate to lower the humidity as well as cool. What were you expecting as drastically reduced humidity levels?
    Last edited by Jeff; 06-13-2018 at 11:26 AM.

  13. #13
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    419
    Visit Freq
    5.62 visits/week
    Threads
    98
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    Quote Originally Posted by Jeff View Post
    Did you measure the humidity level while it was just in the cooling mode? I think that several responses here suggest that the cooling mode should be adequate to lower the humidity as well as cool. What were you expecting as drastically reduced humidity levels?
    Just running the AC humidity will be in the high 60's to low 70's at times with the temp set on 73-75.

    I just called the MFG and they said DRY mode will drop the temp into the low 60's, so that does match what I'm seeing. Although in the owners manual it clearly says you can set the Temp when in the dry mode. I pointed this out and he said it must be a printing error.

    Most literature on mini splits does say they are not the best dehumidifiers, and several members here say they run a separate dehumidifier with their Mini-splits. I guess I just have to determine what is an acceptable level for humidity for me. The unit has barely moved my electric bill... maybe $15-20 a month. Really don't want to run the electric bill up with another unit running all the time.

  14. #14
    Corporate Member
    DQ
    Tarhead's Avatar
    Nickname
    Mark
    Join Date
    Nov 2005
    Location
    Concord, NC
    Posts
    3,865
    Visit Freq
    6.38 visits/week
    Threads
    348
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    Could the mini split unit be oversized for the space? That would explain the high humidity because it is not running long enough to circulate the air. If you can control the fan speed I would run it on the lowest setting. Keeping the humidity level where you have it will definitely create a mold/mildew problem.

  15. #15
    Senior User
    Nickname
    David
    Join Date
    Jul 2016
    Location
    Four Oaks, NC
    Posts
    419
    Visit Freq
    5.62 visits/week
    Threads
    98
    Classifieds
    0

    Re: Mini-Split, Dehumidifier ??

    Quote Originally Posted by Tarhead View Post
    Could the mini split unit be oversized for the space? That would explain the high humidity because it is not running long enough to circulate the air. If you can control the fan speed I would run it on the lowest setting. Keeping the humidity level where you have it will definitely create a mold/mildew problem.
    Hmmm... I have a 17 SEER 18,000 BTU unit. Was looking at the 12,000 BTU and got up sold by the MFG when I bought it. They said the 12k would work, but the 18k would work much better and cost difference was less than $200, so I went for it. I'm sure there is an on-line calculator out there somewhere I could try. I have 576 sq ft. 24'x24' with 9.5' ceiling height. R-30 in walls and ceiling + the thin insulation wrap directly behind the metal siding and roof to prevent moisture. So it is well insulated.

    Not sure if the temp gauge on the unit is off, but I had it set on 75 last night and it was 70 degrees inside this morning. Trying to get this regulated is frustrating. Maybe getting a separate dehumidifier is going to be the best option. With the building being well insulated and climate controlled, maybe it won't run up the electric bill.

Similar Threads

  1. Mini-Split, What do you have?
    By DSWalker in forum Workshop Discussion
    Replies: 9
    Last Post: 09-05-2017, 03:30 PM
  2. Mini Split Permit Woes
    By Jeremy Scuteri in forum Workshop Discussion
    Replies: 27
    Last Post: 08-31-2017, 08:43 AM
  3. Anyone using a Mini-Split System?
    By JackLeg in forum Workshop Discussion
    Replies: 13
    Last Post: 07-29-2015, 11:18 AM
  4. Air Conditioning ... Split, Mini-Split, Ice Bucket w/ Fan
    By WoodWrangler in forum Workshop Discussion
    Replies: 19
    Last Post: 04-29-2014, 02:39 PM
  5. Ductless Mini Split - Hut oh, what have I done?
    By Rhythm House Drums in forum Where Can I Find, Buy or Sell
    Replies: 8
    Last Post: 10-28-2011, 07:44 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •