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  1. #53
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    Jun 2007
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    The Twilight Zone
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    Quote Originally Posted by beenthere View Post
    Or.
    The difference between 4 CPH (96 in a 24 hour period) and 3 CPH (72 in a 24 hour period) setting on a stat, in start wattage, is equal to 12 hours of run time in a 30 day period.
    If you had a month that the A/C cycled to the stat CPH setting.

    So. By its self, a start doesn't draw as much as what most first think. But, adds up over a months time.
    Do I get an "at-a-boy" for my numbers?

  2. #54
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,104
    There aren't any atta boys tonight.

    Tonight is dude night.

    So, you got it dude.
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  3. #55
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    6,446
    Quote Originally Posted by beenthere View Post
    Ivent is not needed.

    Those houses that have a humidity propblem do get recommended a 2 stage to help control it. Not cure it. Because the humidity problem is from too much infiltration.
    The 2 stage will have the longer run cycle to keep it to a more comfortable level.

    In this area, people use their A/Cs alot more then you use yours. So you can't compare what you call no load to the rest of the people across the country.
    Around here, at 72* OD temp, A/Cs are running. And they are able to keep the humidty under 55%RH.

    If they want lower, Then I look at the house as a whole. Not just one part. If they can't tighten the house, they don't need 2 stage or a VS blower.

    If they can't tighten the house. Then its a matter of how much thet are wiling to spend on a system for improved humidty control. Weather I push to use a 2 stage, or just a VS blower.

    Improved humidity control, means improved over the old system. Not cured that it will be perfect.

    No one solution is best for every house.

    I have nothing against whole house dehumidifiers, as one of many possible aids to humidity control.
    Its just the average house already has enough infiltration, additional fresh air isn't required.
    And if those homes lowered their infiltration rate, they would have lower humidity, and still have enough fresh air, that additional ventilation is not required.

    I agree that a positive pressure home can control humidity better. But perfection isn't what the average home owner is really looking for.

    Your dehumidifiers are priced for upscale homes. Nothing wrong with that.

    A unit that is stand alone, and simply dehumidifies, no ability to bring in fresh air, would be a good line.
    So would an add on to the central air system. One that just ties into the duct system, and only dehumidifies, no fresh air intake.

    Products that tackle several task, tend to cost more then needed for many applications. And ar hard to justify to the general public.

    In the past, I had several customers interested in whole house dehumidifiers. Until they heard the price.
    Then they fell back to, never needed it before, don't think I need it now.

    Customers need to be able to see an improvment, or suffer from a condition before they will appreciate devices to minimize that condition.
    Our whole house dehus only use fresh air if the home needs fresh air. Not many homes need fresh during cold weather when homes get twice as much natural fresh air because of the stack effect. During the summer only wind provides natural infiltration and with virtially no stack effect. I have monitored several homes in the Allentown PA area with similar results as WI. After I read all your statements, dehumidification is not one of your options of controlling humidity. I feel comfortable in saying dehumidification provide a solution to moisture problems in your typical home. Price out our free standing dehus. A good dehu plus a simple high SEER a/c are competitive to 2 stage a/c and do provide a better solution to humidity problems. Let me demonstrate one for you. If the dehu does not provide humidity control, return it for no cost to you. At 72^F outside temps, while maintaining 50%RH with only a/c, you are not getting an air change of fresh air every 3-4 hours.
    Anyway, I appreciate you expressing your opposing veiws. There are many traditional a/c supporters who will not investigate dehumidifiers as a possible solution to moisture control. I do agree that the majority of customers a willing to make an investment is good dehu. Most that do make the investment agree that dehus provide better humidity control regardless of the a/c load. Next week, I will show the dehu/a/c interaction as WI finally gets some cooling load. Regards TB
    Last edited by teddy bear; 07-09-2008 at 07:36 AM. Reason: missing words
    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. #56
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
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    18,836
    Many systems can control humidity just fine in wet climates.Internal loads are more then you might think.

    We have sold hundreds of two speeds and have no humidity issues.

  5. #57
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    Jan 2004
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    Lancaster PA
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    Cool, I'll be waiting for the results.
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  6. #58
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    Aug 2003
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    466
    Quote Originally Posted by adrianf View Post
    Everything

    One man's high humidity is another man's design conditions. The question I have is; is the structure getting all water logged with the set back? It's not uncommon for us to go into a vacant (seasonal) home where the a/c has failed and the temps are over 90F but the RH (not absolute) is in the low/mid 40's. Is the humidity less because of the warmer air will hold more vapor? Which is the way it's taught or is the mositure in the structure? And if the RH is lower with the warmer temps where does the structure get the moisture from that it doesn't get when the humidity is higher under normal operating conditions. Or does the vapor content of the surrouinding air have nothing to do with it?

    Again back to the house as a system. Unoccupied house, no cooking, no cleaning, and no humans with a good pressure and thermal barrier in place.
    Drop the temperature of a 90 degree dwelling with low 40&#37; humidity to 72 degrees and the humidity level rises to over 70%. The rate of absorbtion as well as the rate of evaporation of moisture from different materials varies from an hour or so for paper products to up to 72 hours for wood products. A dwelling that has been allowed to warm up over a period of time is going to have moisture absorbed in all permeable materials. Even though the air in the dwelling may decrease fairly rapidly when the cooling is turned on, the moisture in the dwellings materials will take up to 72 hours to level out to the lower temperature. This is why you see people setting thermostats at 72 degrees or so to initially cool an area but within 8 hours they are setting the thermostat up a couple of degrees. As the moisture level in the area decreases, the air feels cooler at the same temperature.

  7. #59
    Join Date
    Aug 2003
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    466
    Quote Originally Posted by beenthere View Post
    I'll let you run a spread sheet on this yourself.

    Take a unit that has a 150 AMP LRA.
    And a RLA of 25.

    Now figure out how much wattage it really draws on start. Lets say it does not have a hard start kit. So lets say it starts extra slow. And go with 5 seconds of drawing LRA.
    How many watts does it really draw in those 5 seconds.
    And then use 80% of the RLA as its true amp draw when running, and see how long it takes to use the same wattage running as it does to start.

    You will be supprised how little it uses.

    When taken in the context of wattage, starting does use the most in the shortest time period.
    But the time period is small enough that its not as much as you think.
    It takes a fair amount of short cycling to increase the electric bill noticably.
    This is true, but it is only taking into consideration one factor of what increases energy usage with shorter cycles. Other considerations are how long it takes each cycle for a system to reach its potential efficiency and the cost of stress put on the compressor and motors in order to start them each time. I have seen cases where installing the same capacity higher efficiency equipment into a home actually increased the energy usage. Several factors are involved; longer time to achieve peak efficiency and consumer setting the temperature lower to account for lack of humidity removal are the major factors when a system is somewhat oversized and a disaster when a system is grossly oversized.

  8. #60
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,104
    The start amp example was only to stress that those amps aren't that much in the big pictiure.

    Low Latent ability of 14, and 15 SEER equipment, is a problem in some installs.
    But its not just the equipment in those cases. It was the contractors lack of proper coil matching that caused the problem.

    A unit may not be at full efficiency when it starts. But its not nearly as low as many thing, or say.

    Unfotunately. To prove the actual efficiency of a unit in teh first 10 minutes. Would require more measuring of operating parameters then what most have meters available to them in the field.

    Atleast I don't carry a device to measure mass refrigerant flow with me.
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  9. #61
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    Jun 2003
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    Madison, WI/Cape Coral, FL
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    Quote Originally Posted by everythingair View Post
    Drop the temperature of a 90 degree dwelling with low 40% humidity to 72 degrees and the humidity level rises to over 70%. The rate of absorbtion as well as the rate of evaporation of moisture from different materials varies from an hour or so for paper products to up to 72 hours for wood products. A dwelling that has been allowed to warm up over a period of time is going to have moisture absorbed in all permeable materials.
    .
    This statement about porus materials absorbing moisture in a 90^F, 40%RH is not correct. All the material in the home will dryout when exposed to 90^F, 40%RH. This includes duct insulation and coils. In addition moisture will not diffuse into the home as quickly at this warmer temperature compared to lower temperatures. Google wood drying for more info.

    Quote Originally Posted by everythingair View Post
    Even though the air in the dwelling may decrease fairly rapidly when the cooling is turned on, the moisture in the dwellings materials will take up to 72 hours to level out to the lower temperature. This is why you see people setting thermostats at 72 degrees or so to initially cool an area but within 8 hours they are setting the thermostat up a couple of degrees. As the moisture level in the area decreases, the air feels cooler at the same temperature.
    After the home cools down to 75^F, the materials in the home absorb moisture from the air if the %RH is +40%RH. This helps not hurts. This is basic physics. Please be open minded about this facts. Part of our bussiness deals with structural drying wet buildings. Materials dry faster at 90^F, 40%RH than 75^F, 50%RH. Also consider electrical utilities promote t-stat save 10% electrical savings for each degree of temp set-up. If your are neverous about 90^F, set-up to 80^F or whatever when unoccupied. Or is no way we can reduce energy consumption with current a/c equipment? 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"

  10. #62
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    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
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    6,446
    Quote Originally Posted by beenthere View Post
    In this area, people use their A/Cs alot more then you use yours. So you can't compare what you call no load to the rest of the people across the country.
    Around here, at 72* OD temp, A/Cs are running. And they are able to keep the humidty under 55%RH.

    If they want lower, Then I look at the house as a whole. Not just one part. If they can't tighten the house, they don't need 2 stage or a VS blower.
    .
    Here is interesting info. I pulled up the weeks temp/dew points for Lancaster/Madison from wonderground.com. I actually have more of a sensible cooling load than you did. I see you had a hotter June than we did. I do have heavy shade, black roof, and a deep basement. Regards TB
    Attached Images Attached Images  
    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"

  11. #63
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    Jan 2004
    Location
    Lancaster PA
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    68,104
    Your temp drops are quicker then we had here, and lower.
    So our A/C load was a longer period of time in hours, per day. So an A/C would tend to be used more and of course remove humidity. Were as with your lower dew point, it wouldn't remove as much.
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  12. #64
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    Aug 2003
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    Quote Originally Posted by teddy bear View Post
    This statement about porus materials absorbing moisture in a 90^F, 40%RH is not correct. All the material in the home will dryout when exposed to 90^F, 40%RH. This includes duct insulation and coils. In addition moisture will not diffuse into the home as quickly at this warmer temperature compared to lower temperatures. Google wood drying for more info.


    After the home cools down to 75^F, the materials in the home absorb moisture from the air if the %RH is +40%RH. This helps not hurts. This is basic physics. Please be open minded about this facts. Part of our bussiness deals with structural drying wet buildings. Materials dry faster at 90^F, 40%RH than 75^F, 50%RH. Also consider electrical utilities promote t-stat save 10% electrical savings for each degree of temp set-up. If your are neverous about 90^F, set-up to 80^F or whatever when unoccupied. Or is no way we can reduce energy consumption with current a/c equipment? Regards TB
    So, may I assume that you condone allowing a home to increase in temperature? Are you saying that mold growth will not be promoted with higher temperatures due to humidity issues? Are all of the people with vacation homes in Florida and other Gulf regions who have their cooling systems being controlled with humidistats while the homes are unoccupied wrong? Are you saying that the humidity level of the air does not increase in percentage as the temperature of that air decreases in temperature?

    I don't care to get into a battle of sales hype data vs common sense and real issues. If there is humidity in the air, it is going to be absorbed into the materials that air comes in contact with. Also, the 90 degree with 40% humidity is not really a very good example of humid conditions.

  13. #65
    Join Date
    May 2007
    Location
    Naples, Fl
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    889
    There is some good info in this study. Take note these are not high end houses with dual capacity air conditioners. Please please open your minds to the three reccommended SUMMER time statigies even if what you have been taught or believe is being contradicted. Also embrace the problem of the shoulder months touched on in this text.

    And no this is not the end all to beat all but it is controlled, recorded and verified data.

    This is from the Florida Solar Energy Center and yes sometimes they can be faulted. They do not have a commercial interest, a dog in the fight, a cat in the racket or a horse in the race.

    http://www.fsec.ucf.edu/en/publicati...CR-1626-06.pdf
    Last edited by adrianf; 07-09-2008 at 03:09 PM. Reason: interst to interest

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