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  1. #1
    Join Date
    Nov 2011
    Posts
    33

    Humidity Control in Beach Home

    We have a 1300 square foot beach house (two stories) in the carolinas which is often unused. I am considering adding a dehumidifier to both lessen the load on the AC and to address times when the temperature may not require AC. I have a few questions that I would welcome feedback on:

    1. Would it be better to install a whole house dehumidifier as part of the HVAC system or as an independent unit. The advantage (as I see it) to installing indpendently is that I could have an intake in the upstairs and and supply in the downstairs and thus only need one unit for the whoel house (I have a walk in attic which would make this very easy to do). Otherwise, I have HVAC systems on both floors, so I would either have to get two dehumidifiers or just pick one floor. Are there other considerations between an independent or HVAC set up?

    2. Since this is not a primary residence, should I be concerned about fire issues or water leakage issues with a dehumidifier? A quick internet search pulls up a lot of fire recalls for dehumidifiers. I'm a little concerned with leaving one running for weeks at a time when I am not there.

    3. Any other thoughts for controlling humidity at a beach house which is often vacant?

    Thanks!

  2. #2
    Join Date
    Jul 2011
    Location
    East coast USA
    Posts
    973
    might want to just add a good programmable stat that measures temp and Humidity. set the temp and keep it in auto.. Or set the stat to run the fan a few hours a day and in auto the rest...If you ac is good no need to add anything else.

  3. #3
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,452
    Quote Originally Posted by unc99 View Post
    We have a 1300 square foot beach house (two stories) in the carolinas which is often unused. I am considering adding a dehumidifier to both lessen the load on the AC and to address times when the temperature may not require AC. I have a few questions that I would welcome feedback on:

    1. Would it be better to install a whole house dehumidifier as part of the HVAC system or as an independent unit. The advantage (as I see it) to installing indpendently is that I could have an intake in the upstairs and and supply in the downstairs and thus only need one unit for the whoel house (I have a walk in attic which would make this very easy to do). Otherwise, I have HVAC systems on both floors, so I would either have to get two dehumidifiers or just pick one floor. Are there other considerations between an independent or HVAC set up?

    2. Since this is not a primary residence, should I be concerned about fire issues or water leakage issues with a dehumidifier? A quick internet search pulls up a lot of fire recalls for dehumidifiers. I'm a little concerned with leaving one running for weeks at a time when I am not there.

    3. Any other thoughts for controlling humidity at a beach house which is often vacant?

    Thanks!
    Better late than ever? The only way to really maintain <50%RH is a small whole house dehumidifier like the Ultra-Aire 70H. I suggest that you place the unit in an area not sensitive to soise and accessible to a drain and a/c ducts. Utility rooms or attach garages work. An 8" return from an open part of the home and a supply to any of the a/c supply ducts works. By using the a/c supply, the dry air is circulated throughout the home. Also the a/c ducts get dried out while maintaining <50%RH in the home. Locate the dehumidistat near the return to the dehumidifier. A good a/c contractor will be able to install and service this simple device.
    This type of install is not noticeable in the home. Also the Ultra-Aire is the most efficient and reliable dehumidifier available.
    REgards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  4. #4
    Join Date
    Nov 2011
    Posts
    33
    Thanks for the replies.

    The Ultra Aire 70H doesn't have a port for fresh air intake, and references adding a "T" to the regular intake to have an offshoot return line for fresh air. I presume this means the wall control cannot control ventilation and you can only adjust manually by adding a twist damper in the T? Do the bigger models (such as the 90H and above) which do have a dedicated intake port for fresh air allow this port to open/closed mechanically by the wall control?

    Thanks in advance

  5. #5
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,452
    Quote Originally Posted by unc99 View Post
    Thanks for the replies.

    The Ultra Aire 70H doesn't have a port for fresh air intake, and references adding a "T" to the regular intake to have an offshoot return line for fresh air. I presume this means the wall control cannot control ventilation and you can only adjust manually by adding a twist damper in the T? Do the bigger models (such as the 90H and above) which do have a dedicated intake port for fresh air allow this port to open/closed mechanically by the wall control?

    Thanks in advance
    The DEH 3000 controls the %RH and fresh air ventilation. The control works with all of the Ultra-Aire dehumidifiers. Yes the fresh air damper is connected to a shared tee. When the damper opens fresh air enters the duct routed into the dehu. Works well. When closed all of the air comes from the home. The UA 70H is large enough to handle homes upto 2,500 sqft.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  6. #6
    Join Date
    Nov 2011
    Posts
    33
    Just to follow up on this...just about ready to move forward. Is there a difference between the XT models and the regular models. Am considering either the 90H model or the XT105H model. Is the only difference the energy efficiency benefit of the XT or are there other benefits to the XT model? Also, does the positive pressure created by these devices run the risk of pushing moisture in the walls? Thanks!

  7. #7
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,452
    Quote Originally Posted by unc99 View Post
    Just to follow up on this...just about ready to move forward. Is there a difference between the XT models and the regular models. Am considering either the 90H model or the XT105H model. Is the only difference the energy efficiency benefit of the XT or are there other benefits to the XT model? Also, does the positive pressure created by these devices run the risk of pushing moisture in the walls? Thanks!
    The Ultra-Aire XT is the highest eff. dehu known to man @ +7-8 lbs./pints per KWH. 90H is a 10 year old design with +5 lbs. per KWH. In high load conditions, I favor the XT 105 unit.
    Thanks for the support. Keep us posted.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  8. #8
    Join Date
    Nov 2011
    Posts
    33
    Thanks very much...this is very helpful. Sorry but I have a couple more questions:

    1. I can either link up the dehumidifier with the upstairs or downstairs HVACs (but not both), or run an independent duct system where it draws from the upstairs and supplies to downstairs (have a walk in storage place where I could easily do this). I'm leaning towards the latter as my impression is that this will create a loop through the whole house, but any thoughts welcome. The home is 900 square feet first floor, 600 square feet second floor, and the second floor seems to have higher humidity. I would place the return on the second floor at the top of the stairs.

    2. Is there such thing as too much dehumidifier? I'm thinking of spending extra for the XT105 since this is a long term purchase and the humidity is an issue year round (home is a few hundred yards from the ocean). The UA website says the XT105 is for 2500 square feet homes...Overkill in a 1600 square feet home?

    3. Does Ultra Aire offer a remote access thermostat like some other companies?

    Thanks very much!

  9. #9
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,452
    Quote Originally Posted by unc99 View Post
    Thanks very much...this is very helpful. Sorry but I have a couple more questions:

    1. I can either link up the dehumidifier with the upstairs or downstairs HVACs (but not both), or run an independent duct system where it draws from the upstairs and supplies to downstairs (have a walk in storage place where I could easily do this). I'm leaning towards the latter as my impression is that this will create a loop through the whole house, but any thoughts welcome. The home is 900 square feet first floor, 600 square feet second floor, and the second floor seems to have higher humidity. I would place the return on the second floor at the top of the stairs.

    2. Is there such thing as too much dehumidifier? I'm thinking of spending extra for the XT105 since this is a long term purchase and the humidity is an issue year round (home is a few hundred yards from the ocean). The UA website says the XT105 is for 2500 square feet homes...Overkill in a 1600 square feet home?

    3. Does Ultra Aire offer a remote access thermostat like some other companies?

    Thanks very much!
    Over-sizing a dehumidifier is similar to over-sizing the a/c. It means more short cycling not a lack of %RH control. Number of occupants, the amount of fresh air ventilation/infiltration, and your %RH settings determine the run time.
    If you do mined a few hours of +50%RH occasionally, a smaller unit will do the job. The UA XT105H is +30% more capacity and 40% more efficiency.

    The Ultra-Aire DEH 3000 R has a remote sensor which is located away of from the low voltage control. Of course the low voltage control is usually remoted from the dehumidifier.
    Hope this helps.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

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