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    Default High Humidity with Heat Pump

    What would cause high humidity(~ 65%) while cooling a house to 70 degrees with a heat pump?

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    Default Re: High Humidity with Heat Pump

    The first question all HVAC contractors are going to ask is; was the system sized correctly. If the unit is over sized it does not run long enough to remove the humidity. Short cycles of on.

    The other question, and in my opinion the more common problem, is do you have a moisture barrier under the house? If you are punching in more humidity than the a/c can remove you have a problem.

    I don't know that I would call 65% all that high anyway.

    Last edited by Vern Heiler; 09-08-2009 at 06:02 AM.

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    Default Re: High Humidity with Heat Pump

    I agree with Vern.

    Does the house have 65% humidity or is that in the air stream at a register?

    How did you measure the humidity and with what?

    What is the SF of the home and what is the tonnage or BTU of the unit?

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Joe Buemi View Post
    What would cause high humidity(~ 65%) while cooling a house to 70 degrees with a heat pump?
    Some of the possibilities are:
    improperly sized unit which keeps the unit from running long enough to drop the humidity,
    uncontrolled moisture source (showers, cooking, wet exterior weather),
    clogged drain or lack of trap on a draw through system,
    improper system charge, valve function, or defective compressor which raises the evaporator temperature near or above dew point.

    I'm sure there are other things possible, but you really need more information to even begin looking.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jim Luttrall View Post
    but you really need more information to even begin looking.
    That is key, and you do not have enough information, and did not give us enough information, to form viable answers.

    Sizing would be my first guess to, then common sense would kick in and say "What else is going on?", and THAT is the likely problem, unless your system is so vastly oversized your home feels like a meat cooler.

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    Default Re: High Humidity with Heat Pump

    All good advice but the most likely problem is "coil blow back".

    A problem with the condensate drainage or a dry trap is causing the condensation to blow back all over the coil. The airhandler then sends all of this moisture right back into the house.

    Bruce King, B.A. King Home Inspections, LLC
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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Bruce King View Post
    All good advice but the most likely problem is "coil blow back".

    A problem with the condensate drainage or a dry trap is causing the condensation to blow back all over the coil. The airhandler then sends all of this moisture right back into the house.
    The air leaving the coil is at 100% humidity, how does it pick up more?


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    Default Re: High Humidity with Heat Pump

    Actually it leaves the coil at around 95 percent humidity and goes to 100 percent when condensation is incorrectly blowing all over it. It also stays at 100 percent for the time period when the fan is blowing and condensor is off such as the end of the cycle because water is blowing all over the inside.

    If blow back is not the problem, the speed of the air across the coil can be lowered to help lower the humidity (by getting the coil temperature lower).

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Bruce King View Post
    Actually it leaves the coil at around 95 percent humidity and goes to 100 percent when condensation is incorrectly blowing all over it. It also stays at 100 percent for the time period when the fan is blowing and condensor is off such as the end of the cycle because water is blowing all over the inside.

    If blow back is not the problem, the speed of the air across the coil can be lowered to help lower the humidity (by getting the coil temperature lower).
    I disagree. When the air leaves the coil surface it is at dew point and can hold no more moisture until it warms.


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    Default Re: High Humidity with Heat Pump

    95 or 100 no big deal, the 95 actually came out of a textbook.

    The main thing is experience, the guy who told me that coil blow back will put humidity back into the house owns a large hvac company and has been in the business for decades and does a lot of commercial work too.

    Some Trane gas packs are bad about doing this, since they suck air when the p-trap is dry at the start of the season.


    More on tweaking airflow:

    Humidity control can be achieved in different parts of the country with the same equipment by simply changing the speed of the air across the coil. This eliminates having to sell specific equipment based on the varying climates.

    Bruce King, B.A. King Home Inspections, LLC
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    Default Re: High Humidity with Heat Pump

    If the reference is to interior humidity levels of 65% they are way too high.

    At 70º indoor dry bulb with the outdoor relative humidity levels we have been experiencing here in KY it won't be long before moisture is condensing inside the exterior wall cavities.

    Could be a number of things contributing to this problem Joe.

    Infiltration and duct leakage come to mind off the top of my head.

    Measured Performance more than just a buzzword

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by DavidR View Post
    If the reference is to interior humidity levels of 65% they are way too high.

    At 70º indoor dry bulb with the outdoor relative humidity levels we have been experiencing here in KY it won't be long before moisture is condensing inside the exterior wall cavities.

    Could be a number of things contributing to this problem Joe.

    Infiltration and duct leakage come to mind off the top of my head.
    As Scott said, a lot depends on where the measurement was taken and how accurate the measurement was.

    All of the psychrometric comfort zone charts I have seen put the 65% humidity at 70 degrees inside the zone. I don't think it should be considered bad.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    As Scott said, a lot depends on where the measurement was taken and how accurate the measurement was.

    All of the psychrometric comfort zone charts I have seen put the 65% humidity at 70 degrees inside the zone. I don't think it should be considered bad.
    Scrapping the bottom of the chart with those numbers Vern, to tell a customer that's acceptable isn't going to be in their best interest.
    Would you like the interior of your home at those conditions?

    70º outdoor dewpoint like we've had here and 70º interior dry bulb temperature with 65% interior humidity is a recipe for disaster.
    The walls are at dewpoint in those conditions.

    If you tweak those conditions a little more you can start to grow fungus on and in the walls.
    Pushing the interior humidity above 55% regardless of whatever any ASHRAE chart says is a bad idea.

    Maybe Joe will reply back and give us some specifics on the job.
    If he took his measurements in the airstream I will be really surprised.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by DavidR View Post
    Scrapping the bottom of the chart with those numbers Vern, to tell a customer that's acceptable isn't going to be in their best interest.
    Would you like the interior of your home at those conditions?

    70º outdoor dewpoint like we've had here and 70º interior dry bulb temperature with 65% interior humidity is a recipe for disaster.
    The walls are at dewpoint in those conditions.

    If you tweak those conditions a little more you can start to grow fungus on and in the walls.
    Pushing the interior humidity above 55% regardless of whatever any ASHRAE chart says is a bad idea.

    Maybe Joe will reply back and give us some specifics on the job.
    If he took his measurements in the airstream I will be really surprised.


    David, if we told Joe to raise the temperature to 78 degrees and the humidity went to 50%, would that be ok?

    Because if he were to take the air in his house now, 70 deg. and 65%, and heat it to 78 deg., it would be at 50% relative humidity.

    At 70% and 70deg. the dew point is 60 deg. so the walls would have to be cooled to 60 or lower for condensation.

    Last edited by Vern Heiler; 09-14-2009 at 05:26 AM. Reason: add wall condensation

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    David, if we told Joe to raise the temperature to 78 degrees and the humidity went to 50%, would that be ok?

    Because if he were to take the air in his house now, 70 deg. and 65%, and heat it to 78 deg., it would be at 50% relative humidity.

    At 70% and 70deg. the dew point is 60 deg. so the walls would have to be cooled to 60 or lower for condensation.
    Yes it would change conditions if the home was warmed up, would reduce the wetting potential in those walls.
    In your example if it reached 60º it would be raining from his ceiling.

    Those surface temperatures are only concerned with what the humidity is relative to them.
    If the outdoor dewpoint is 70º and the interior dry bulb is 70º that is at saturation.
    The high indoor humidity is the whole purpose they are driving the indoor temps down to begin with.

    Good discussion.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by DavidR View Post
    Yes it would change conditions if the home was warmed up, would reduce the wetting potential in those walls.
    In your example if it reached 60º it would be raining from his ceiling.

    Those surface temperatures are only concerned with what the humidity is relative to them.
    If the outdoor dewpoint is 70º and the interior dry bulb is 70º that is at saturation.
    The high indoor humidity is the whole purpose they are driving the indoor temps down to begin with.

    Good discussion.
    In my example the walls only must be droped to 60 deg. for dew point to be reached, the air temp would have to remain at 70.

    How does mixing outdoor dew point have anything to do with indoor?


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post

    How does mixing outdoor dew point have anything to do with indoor?
    Moisture drive through the wall assemblies.

    That outdoor air is constantly trying to get indoors many times with the help of various building and mechanical defects.
    When air that is already saturated hits a surface that is at the same dewpoint temperature you get condensation. Just like taking a glass of ice tea outside on a humid day or the suction line sweating back on a properly charged condenser.
    It's the whole reason why walls start to grow mold inside the wall cavities versus on the interior of the building shell.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by DavidR View Post
    It's the whole reason why walls start to grow mold inside the wall cavities versus on the interior of the building shell.
    Because the dew point has moved to someplace within that wall cavity, possibly the backside of the interior drywall, possibly the inside of the exterior sheathing, possibly even in the center of the insulation.

    Years ago I did some consulting on a hotel on the beach, the wall cavity RH was at 99.9%, and, yes, it was "raining" in the walls - the insulation was saturated with water and when the interior drywall was removed, you could pull the insulation out and water would drain out of the insulation.

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    Default Re: High Humidity with Heat Pump

    The numbers I used, 78 deg. and 50% humidity, was not a number I pulled out of my a$$. That is the bulls-eye that is painted on psychrometric charts. A cubic foot of air contains the same amount of water vapor at 70 deg. and 65% humidity as air at 78 deg and 50%.

    Years ago I did some consulting on a hotel on the beach, the wall cavity RH was at 99.9%, and, yes, it was "raining" in the walls
    Relative humidity is just that, relative to the temperature of the air.

    Because the dew point has moved to someplace within that wall cavity, possibly the backside of the interior drywall, possibly the inside of the exterior sheathing, possibly even in the center of the insulation.
    I believe that is a good reason to have "insulation" don't you?


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    I believe that is a good reason to have "insulation" don't you?
    Vern,

    You are missing an important fact I included: there WAS insulation in that wall.

    The dew point had moved to somewhere near the center of the wall cavity ... within the insulation ... thus it was condensing within the insulation.

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    Default Re: High Humidity with Heat Pump

    You are missing an important fact I included: there WAS insulation in that wall.

    The dew point had moved to somewhere near the center of the wall cavity ... within the insulation ... thus it was condensing within the insulation.
    You did not give us the RH of the interior air? Was it at 100%?


    Jerry, if the insulation was functioning the warm humid exterior air would not have reached the cold interior surface, wherever it was.

    The OP situation is 70 deg. and 65%. That is considered the optimum amount of moisture contained in the volume of air.

    The exterior RH and the interior RH are not relative to each other. The only surface that RH is relative to is the surface it can come in contact with.

    Last edited by Vern Heiler; 09-14-2009 at 09:45 AM. Reason: double quotes

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    The exterior RH and the interior RH are not relative to each other.
    I know that.

    The only surface that RH is relative to is the surface it can come in contact with.
    With my point being ... THAT surface COULD BE LOCATED ANYWAY ... yes, even IN the wall.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    With my point being ... THAT surface COULD BE LOCATED ANYWAY ... yes, even IN the wall.
    Your problem was with insulation, not the RH.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Your problem was with insulation, not the RH.

    No, the problem was the location of the dew point, which caused a problem with the insulation, which made the location of the dew point worse, which caused an even worse problem with the insulation, which ... and it all goes downhill from there, but "the insulation" was not the original "cause" of the problem, "the insulation" was the first casualty of the problem.

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    Default Re: High Humidity with Heat Pump

    If it was not an insulation problem how did the dew point move to the wrong side of it?


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    Default Re: High Humidity with Heat Pump

    Vinyl wallpaper and hurricanes as a vapor and moisture driving force, among other contributing factors.

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    Default Re: High Humidity with Heat Pump

    hurricanes
    Hmmmmm, kinda forgot to mention that .

    But the only way condensation formed was for warm moist air to come in contact with a cold surface. "Insulation" seperation of one thing from another.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Hmmmmm, kinda forgot to mention that .
    You mean you kinda forgot to CONSIDER that.

    But the only way condensation formed was for warm moist air to come in contact with a cold surface. "Insulation" seperation of one thing from another.
    "But the only way condensation formed was for warm moist air to come in contact with a cold surface."

    And there WAS insulation in those walls. THE INSULATION ... WAS NOT ... THE PROBLEM. Which is what you were saying it was.

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    Default Re: High Humidity with Heat Pump

    If hurricanes are an important factor, and the air was condensing inside the wall, then the insulation was not doing its job due to getting wet from hurricanes, not that the indoor air was above 50% humidity.

    The moisture condensed from the outdoor air not the indoor. To be from the indoor air, the indoor surface of the wall would have to be warmer than the exterior wall or center of the insulation. You would have to blow cold air into the wall cavity for this to happen. Still sounds like insulation failure to me.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    If hurricanes are an important factor, and the air was condensing inside the wall, then the insulation was not doing its job due to getting wet from hurricanes, not that the indoor air was above 50% humidity.
    And NOT a fault of the insulation.

    Which you kept trying to say was the problem.

    The moisture condensed from the outdoor air not the indoor.
    No kidding.

    And that condensation was caused by DEW POINT LOCATION ... which is what I have been telling you.

    The dew point moved as the vapor changes affected the temperature and RH inside the wall cavity, and the dew point IS WHAT CAUSES the condensation.

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    Default Re: High Humidity with Heat Pump

    The dew point moved as the vapor changes affected the temperature and RH inside the wall cavity, and the dew point IS WHAT CAUSES the condensation.
    No the dew point is the temperature that air, with a given amount of moisture content, will begin to condense. The dew point never moved! The cold surface is what moved. It moved to a location beyond the interior surface of the wall which is what insulation is supposed to prevent.


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    Default Re: High Humidity with Heat Pump

    Since the interior of the wall cavity is normally/usually "connected" to the outside it is affected by the water vapor pressure of the exterior air. The vapor pressure is related to the dew point directly whereas RH varies in relation to the exterior dry bulb temperature. If some point within the wall cavity is cooler than the outside dew point then the air in contact with that point will be cooled below the dew point and condensation will occur. Cooling the interior of a structure below the dew point of the exterior air will always cause this problem. The forgoing assumes a reasonable barier to vapour travel on the inside of the building envelope.


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    Default Re: High Humidity with Heat Pump

    Cooling the interior of a structure below the dew point of the exterior air will always cause this problem.
    Really! I guess we better tell everyone south of Minnesota to turn there thermostats up to somewhere above 80. Give me a break!


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Really! I guess we better tell everyone south of Minnesota to turn there thermostats up to somewhere above 80. Give me a break!
    Just need to move the vapor barrier to the outside wall instead of the inside.
    See the BSC article and there is one which Dr. Joe lists as one of the top ten dumb things to do when building in the south... something about Yankees not being allowed
    BSI-015: Top Ten Dumb Things To Do In the South —

    Jim Luttrall
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    Default Re: High Humidity with Heat Pump

    Thanks Jim. I think Vern missed the point. Climate is the determining factor in where a vapor barrier is placed or even if there should be one. North Dakota buildings don't work well in Florida and visa versa but Boyles laws are inviolate.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    No the dew point is the temperature that air, with a given amount of moisture content, will begin to condense. The dew point never moved! The cold surface is what moved. It moved to a location beyond the interior surface of the wall which is what insulation is supposed to prevent.
    Vern,

    Not sure you you've been drinking today, but ... the wall has not moved.

    The DEW POINT has moved.

    Not referring to moving in degrees, which it also has moved, but referring to its location in the wall.

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    Default Re: High Humidity with Heat Pump

    [quote]
    I think Vern missed the point. Climate is the determining factor in where a vapor barrier is placed or even if there should be one./QUOTE]

    Can you explain the code requirement of having the vapor barrier on the conditioned side of the insulation? North, South, East or West.

    And Boyle's law deals with temperature/pressure relationship in a closed container. It has no relationship to this discussion.

    Last edited by Vern Heiler; 09-14-2009 at 05:26 PM. Reason: add Boyle's

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Vern,

    Not sure you you've been drinking today, but ... the wall has not moved.

    The DEW POINT has moved.

    Not referring to moving in degrees, which it also has moved, but referring to its location in the wall.
    Jerry,

    The normal location of the coldest surface of the exterior wall is the paint on the interior side of the wall. If the insulation becomes wet the location of the coldest surface, relative to the exterior wall, moves toward the exterior surface of the wall. The dew point does not move unless you remove or add moisture to the air.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    The dew point does not move unless you remove or add moisture to the air.
    Vern, Vern, Vern,

    What have you been sipping on?

    THAT'S WHAT I SAID HAPPENED ... the dew point moved ... and you've been arguing against the dew moving, insisting that it does not move.

    The dew point moves all during the day, and night, and changes by the day, and the week, and the month ... the dew point is not fixed as nothing else is fixed either.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Vern, Vern, Vern,

    What have you been sipping on?

    THAT'S WHAT I SAID HAPPENED ... the dew point moved ... and you've been arguing against the dew moving, insisting that it does not move.

    The dew point moves all during the day, and night, and changes by the day, and the week, and the month ... the dew point is not fixed as nothing else is fixed either.
    Jerry, If you are going to be an authority on the subject you need to look up some definitions. Here's one to start with:

    Dew Point Temperature
    The temperature of moist air saturated at the same pressure and humidity ratio. Or more simply the temperature at which water vapor will begin to condense from a sample of air.



    The sample of air could be a milk jug with a cap on it. The moisture content is constant, therefore the dew point is constant for that sample.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Jerry, If you are going to be an authority on the subject you need to look up some definitions. Here's one to start with:

    Dew Point Temperature
    The temperature of moist air saturated at the same pressure and humidity ratio. Or more simply the temperature at which water vapor will begin to condense from a sample of air.


    The sample of air could be a milk jug with a cap on it. The moisture content is constant, therefore the dew point is constant for that sample.
    Vern,

    Still not admitting you were wrong so you are trying to confuse and misdirect the discussion.

    Not absolutely sure here, but to my knowledge we HAVE NOT been talking about a sample in a capped MILK JUG, but we have been talking about a structure's wall.

    Please DO correct me if I am wrong and we have been talking about a capped milk jug.

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    Default Re: High Humidity with Heat Pump

    If we have 78 deg. air that contains 50% RH it has 10,299 ppm water. If we take a closed container of that air, its dew point is 57.979 degrees at the same pressure. The only way to change that dew point temperature is to add or remove moisture from that sample of air.

    In your example where moist air condenses on anything other than the paint on the interior wall surface, where it should if that surface is at or below DP, moisture was not added or removed from the air. The first cold surface the air reached did move.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    If we have 78 deg. air that contains 50% RH it has 10,299 ppm water. If we take a closed container of that air, its dew point is 57.979 degrees at the same pressure. The only way to change that dew point temperature is to add or remove moisture from that sample of air.

    In your example where moist air condenses on anything other than the paint on the interior wall surface, where it should if that surface is at or below DP, moisture was not added or removed from the air. The first cold surface the air reached did move.
    Vern,

    You need to quick sucking out that sample of moisture laden air from that jug and put the cap back on it: 1) you are changing the air in the jug; 2) you need to clear your head and go back and read, and understand, what has been posted.

    I thought you might have been sipping something, but now I suspect you are just sucking air ... stale, moist air at that..

    Jerry Peck, Construction / Litigation Consultant
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    Wink Re: High Humidity with Heat Pump

    Vern

    When looking at a cross section of the building envelop there is a change of temperature from the paint on the inside that is at the interior temperature of the building to the exterior finish of the wall that is at the outside air temperature (or higher if the sun is beating down on it). The air encapsulated within the wall that for this argument sake, we can consider as being exposed to the outside air and isolated from the inside air by a vapour (air) barrier, will have the same partial pressure conditions as the outside air. The important partial pressure is that of the water vapour in the outside air which will be in equilibrium with the air encapsulated within the wall structure. As we move through the wall from outside to inside, and the inside surface is colder than the point of condensation (dew point), we will eventually come to a point where the air is cooled below the point at which it can hold all the water disolved in it. I never said this is the way a wall should be built south of the 49th parallel. Indeed, many in the south seem to have the idea that the walls north of 49 are made of water in another state (sic).


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Vern,

    You need to quick sucking out that sample of moisture laden air from that jug and put the cap back on it: 1) you are changing the air in the jug; 2) you need to clear your head and go back and read, and understand, what has been posted.

    I thought you might have been sipping something, but now I suspect you are just sucking air ... stale, moist air at that..
    Wow Jerry, you gave up easy! Reverting to diatribe when facts get in the way.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Wow Jerry, you gave up easy! Reverting to diatribe when facts get in the way.

    Vern,

    (sigh)

    So far, you have not presented ANY FACTS which say other than I have been saying.

    Then you tried to misdirect to your sample in a capped milk jug, which has no relevance to what we are discussing.

    Now you are trying to redirect from you to me and saying that *I* have changed and you have not.

    Please, stick to the facts and to the discussion ... don't bother trying to misdirect or redirect ... simply follow the discussion as it progresses along.

    THE STRUCTURE (and its wall) NEVER MOVED.

    THE DEW POINT ... MOVED.

    BOTH in relation to its location in the wall and to the temperature and RH in the environment around the dew point. The dew point is neither stationary in time or in physical location, it it totally dependent on what is going on around it.

    Your first mistake, I shall point out AGAIN, was in NOT CONSIDERING the environmental effects, such as hurricanes.

    Here is an example:
    - outside temperature is 95 degree and the inside temperature is 70 degrees (I don't know what the RH was for either)
    - along comes a hurricane
    - along comes NO POWER ... did I just hear another drop of your jaw ... along with a 'Oh, I did NOT CONSIDER that either.'

    Do you really think the indoor temperature is now lower than the exterior temperature?

    Where is the dew point now? Is it still where it was before?

    Are you waking up yet?

    I'm not into diatribe mode, I just cannot understand a smart person like you insisting on what you are insisting on without actually thinking about what may be going on, instead of trying to prop up your original position with some "capped milk jug" thing.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Vern,

    (sigh)

    So far, you have not presented ANY FACTS which say other than I have been saying.

    Then you tried to misdirect to your sample in a capped milk jug, which has no relevance to what we are discussing.

    Now you are trying to redirect from you to me and saying that *I* have changed and you have not.

    Please, stick to the facts and to the discussion ... don't bother trying to misdirect or redirect ... simply follow the discussion as it progresses along.

    THE STRUCTURE (and its wall) NEVER MOVED.

    THE DEW POINT ... MOVED.

    BOTH in relation to its location in the wall and to the temperature and RH in the environment around the dew point. The dew point is neither stationary in time or in physical location, it it totally dependent on what is going on around it.

    Your first mistake, I shall point out AGAIN, was in NOT CONSIDERING the environmental effects, such as hurricanes.

    Here is an example:
    - outside temperature is 95 degree and the inside temperature is 70 degrees (I don't know what the RH was for either)
    - along comes a hurricane
    - along comes NO POWER ... did I just hear another drop of your jaw ... along with a 'Oh, I did NOT CONSIDER that either.'

    Do you really think the indoor temperature is now lower than the exterior temperature?

    Where is the dew point now? Is it still where it was before?

    Are you waking up yet?

    I'm not into diatribe mode, I just cannot understand a smart person like you insisting on what you are insisting on without actually thinking about what may be going on, instead of trying to prop up your original position with some "capped milk jug" thing.
    You really don't have a clue do you!

    You enter the thread backing up a claim that RH above 50% will travel through the wall and condense in the insulation. You have a story to verify your position, but forget to mention the moisture in the wall might be due to a hurricane. Hurricanes are not normally in a load calculation or any other calculation I know of. Then you incest that dew points change without changing the vapor content of the air. You will not concede that wet insulation may be colder than dry and its surface may be at DP. Then you grab hold of an explanation using a known container (milk bottle) to try to discredit.

    Looking a little republican here Jerry


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    but forget to mention the moisture in the wall might be due to a hurricane. Hurricanes are not normally in a load calculation or any other calculation I know of.
    Vern,

    The only one without a clue here is you.

    You have your mind preset NOT TO INCLUDE ANY FACTORS OTHER THAN those in your head.

    *I* should not be the one needing to tell you (if you are aware of what is going on) about outside conditions affecting what is going on in and with the walls.

    *YOU* should have been opened minded and thinking about the conditions which COULD cause things other than what was in your little chart.

    *MY* entire point was that you were too focused on your chart to really think about what was going on.

    *YOU* proved that out all by yourself.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    *MY* entire point was that you were too focused on your chart to really think about what was going on.
    Lets talk about what was going on.

    (1) The original post questioned why he had 65% at 70 deg.

    I responded with a possible way to reduce the RH (vapor barrier) and stated that the RH was not that bad. This flew in the face of the chicken littles of the board.

    (2) You jump in with story of moisture condensing in the wall and the insulation was not the problem but that a moving dew point was. I tried to explain that a dew point is a temperature not a place and only changes with the addition or removal of moisture. (that escapes you still)

    (3) You divulge a minor detail, HURRICANE! My god man when was that normal! I deduce that if the hurricane wet the insulation the insulation would conduct the cold from the inside wall to a position somewhere in the wall ( the position of the condensing surface moved toward the exterior wall) That escapes you also.

    (4) With a chart I found that the 70 deg. 65% air has the exact same vapor content as the widely accepted 78 deg, 50% target temp and humidity. 65% is not a high humidity at 70% temp! Also flew in the face of the chicken littles.


  50. #50
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    Red face Re: High Humidity with Heat Pump

    The first item you have to do is to put a set of gauges on the system to determine if it is charged properly, that the superheat and subcooling are at the right size. An overly large sized unit could be the culprit as well as a low charge which is allowing the coils to ice up. Simply lowering the fan speed is not the correct way to go due to the fact that it will allow the coil to maybe start to freeze or be too saturated with condensation thus blowing out wet or fully saturated air in the 100% rh range. Unless you have an airflow meter to determine how many CFM of air the unit is moving in comparsion to the square feet the building is, how many windows,how much insulation,what exposure to the sun and so on. This is why you have a trained HVAC mechanic with an EPA certification to service the equipment to determine the problem.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Lets talk about what was going on.

    (4) With a chart I found ...
    And that is what is still going on ... you have not gotten your head out of that chart to consider the real world and its real effects on what has been stated.

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    And that is what is still going on ... you have not gotten your head out of that chart to consider the real world and its real effects on what has been stated.
    I know Jerry, the facts be damned.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    I know Jerry, the facts be damned.
    Vern,

    No, the facts are the facts, and those FACTS ... INCLUDE ... the fact that the environment around a building affects the building ... AND THE DEW POINT's location.

    Which is something you do not seem to either understand or be willing to acknowledge or admit.

    Your table and chart works fine with your capped milk jug, but as soon as real world occurrences happen you are not allowing yourself to adapt to the changes, which affect your table and chart as the temperature and humidity you are reading from change, meaning your chart is not static, but dynamic with those changes. THAT is what you are not getting or not following.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    AND THE DEW POINT's location.
    Do you have the same problem with light years being a measure of distance not time?


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    Do you have the same problem with light years being a measure of distance not time?
    Huh?

    First you don't understand what is being discussed, or at least it appears that way, and now you are trying to say we need to measure in light-years?

    What do you not understand about "changing" temperatures and humidities?

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Huh?

    First you don't understand what is being discussed, or at least it appears that way, and now you are trying to say we need to measure in light-years?

    What do you not understand about "changing" temperatures and humidities?
    And why do you avoid items 1,2, and 3 of post #49? Or for that matter the rest of 4?

    It is good to know that you have accepted that you do have a diatribe mode. Thats a step in the right direction to your cure .


  57. #57
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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    It is good to know that you have accepted that you do have a diatribe mode. Thats a step in the right direction to your cure .
    And once you accept the error of your posts above you will be in the right direction to your cure.

    Do you, or do you not, agree that the psychometric chart is a static graphical representation of dynamic readings taken as representing one point in time?

    And that, because it is representing dynamic readings the static graphical representation will change when recalculated for each no dynamically changing set of readings?

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    Let’s summarize.

    POST #

    13. DavidR States that if the outdoor DP is 70° and the indoor DB temp is 70°, the outdoor air is at saturation. Well that would be true if the outdoor air was indoors, but its not. That’s why we use something called “INSULATION”. David goes on to say that if the indoor RH goes above 55% then DISASTER AWAITS US ALL! (Ya gotta love the chicken littles of the board!)

    14. I explain that 70° air with a RH of 65% is the same RH as 78° and 50%. I mistakenly assume David knows the indoor air is separate from the outdoor air and state that the DP is 60° for the OP’s condition, 10° below the DB temp.

    15. ??? Still doesn’t know indoor is separate from outdoor! David says if the temp gets to 60° it will rain from the ceilings. ??? What I had stated was that if a surface was at 60° in that 70° 65% air there would be condensation. (How do you get the ceilings to 60° without lowering the air temp?)

    16. David does a little left turn here and does not address the question asked. “How does ID DP relate to OD DP?” States that it is the outdoor air that might get to the interior wall due to faulty insulation. OK, I’ll buy that.

    18. Jerry enters the fray. States that the DP has physically moved, even though a DP is not a physical thing or place (but I understand the confusion). Then backs the idea that high RH will cause walls to sop with moisture. Uses story of motel wall that was saturated with water. (We latter learn the water may have come from a HURRICANE!)

    19. I question the motel story regarding insulation.

    20. Jerry swears there was insulation but somehow the DP had moved (physically) in the wall, and all the moisture was due to condensation. (we still don’t know about the HURRICANE)

    20. Still don’t acknowledge the HURRICANE. Just a little bully tatics.

    21 – 24 Getting a little closer to the HURRICANE. (still thinks DP is a physical location)

    25. I play along with DP being physical. Question, “how did it move?”

    26. Ahh, the HURRICANE. What relevance does a wall damaged by a HURRICANE, have with this discussion?

    27. I state that good insulation (not damaged by a HURRICANE) would prevent warm moist air from contacting the cold surface. (seems like it works pretty well for millions of structures)

    28. I should have known there was a HURRICANE from the beginning? Jerry says the wet insulation was not the problem.

    29. (Hmmm I thought wet insulation was always a problem?) Back to OP question I try dig from Jerry what is the relation of the ID RH?

    30. Nope, insulation was fine (forget the HURRICANE) the DP moved and wet the insulation. Huh?

    31. I try to explain what dew point is. (what a waste of good ink!) Make another point for good insulation.

    32. Steve Z. says if you cool your house to below the OD DP, you will have big problems.

    33. Gonna have a lot of problems in the humid south!

    34 - 35. JL tries to help but doesn’t really want to get in the line of fire.

    36. Jerry gets flustered and starts into diatribe.

    37. Boyle’s Law, come on!

    38. Try again in vain to get Jerry to understand DP and RH.

    39 - 43. In vain verified! Jerry going deep into diatribe mode.

    44. Steve Z. Tries to make Boyle’s Law work. (air pressures are in equilibrium so I don’t see the point he is trying to make) Minimal at best.

    45. Jerry’s diatribe sets in and his shell game starts.

    46 – 48 We turn into kids fighting in the playground. Shame on us!

    49. Short summary.

    50. Cobra, that ground has already been plowed and I’m tired. Been writing two townhouse reports in between post and I hope I haven’t given the wrong one a porcelain sink or something!

    -56. Just more diatribe.

    57. Of course DP’s change, but they change because of the addition or removal of moisture. The OP point was that 65% was too high and condensation will ruin whole cities at this RH. Well it is too high in 78° air, but not in 70° air.










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    Default Re: High Humidity with Heat Pump

    Let's summarize:

    A simple question.

    A single simple question.

    A simply 'yes' or 'no' question.

    Quote Originally Posted by Jerry Peck View Post
    Do you, or do you not, agree that the psychometric chart is a static graphical representation of dynamic readings taken as representing one point in time?

    And that, because it is representing dynamic readings the static graphical representation will change when recalculated for each no dynamically changing set of readings?
    Vern,

    What is it?

    A simple 'yes'?

    A simple 'no'?

    You are going on tangents instead of answering a simple question.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Let's summarize:

    A simple question.

    A single simple question.

    A simply 'yes' or 'no' question.



    Vern,

    What is it?

    A simple 'yes'?

    A simple 'no'?

    You are going on tangents instead of answering a simple question.

    I answered the best I could to a poorly written question at the end of the summary.


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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Vern Heiler View Post
    I answered the best I could to a poorly written question at the end of the summary.
    If that was your lame attempt at an answer to a very simply written question, your answer is only partially correct, meaning that you are still not correct.

    Go back and re-read your poorly written attempt at an answer and see if you can figure out why you are only partially correct.

    Jerry Peck, Construction / Litigation Consultant
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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    If that was your lame attempt at an answer to a very simply written question, your answer is only partially correct, meaning that you are still not correct.

    Go back and re-read your poorly written attempt at an answer and see if you can figure out why you are only partially correct.
    And why would I do that? You have not answered any of my questions and I am not on the stand and you are not Perry Mason.


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    Default Re: High Humidity with Heat Pump

    Vern,

    Quote Originally Posted by Vern Heiler View Post
    You have not answered any of my questions and I am not on the stand and you are not Perry Mason.
    I am addressing these in order: You whipped your little chart out at post #12, ... LONG BEFORE my post with the the dew point moving - post #18.

    Post #12:
    Quote Originally Posted by Vern Heiler View Post
    As Scott said, a lot depends on where the measurement was taken and how accurate the measurement was.

    All of the psychrometric comfort zone charts I have seen put the 65% humidity at 70 degrees inside the zone. I don't think it should be considered bad.
    And you have not answered any questions about your chart, dew point, etc.

    You say that:
    Quote Originally Posted by Vern Heiler
    57. Of course DP’s change, but they change because of the addition or removal of moisture.
    So I am presuming, because you have not explained yourself well at all or answer the other questions, that your statement that dew points change but ONLY because of the addition or removal of moisture ... THAT IS what YOU said.

    I am giving you a chance to further state what causes dew points to move and change.

    Name the thing(s) which affect dew point:
    -
    -
    -
    -
    - (however many there are)

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    Default Re: High Humidity with Heat Pump

    Quote Originally Posted by Jerry Peck View Post
    Vern,



    I am addressing these in order: You whipped your little chart out at post #12, ... LONG BEFORE my post with the the dew point moving - post #18.

    Post #12:


    And you have not answered any questions about your chart, dew point, etc.

    You say that:


    So I am presuming, because you have not explained yourself well at all or answer the other questions, that your statement that dew points change but ONLY because of the addition or removal of moisture ... THAT IS what YOU said.

    I am giving you a chance to further state what causes dew points to move and change.

    Name the thing(s) which affect dew point:
    -
    - The amount of moisture contained in a volume of air.

    also see:Observed Dew Point Temperature: indicates the amount of moisture in the air
    -
    - Read the first line of the second paragraph.
    - (however many there are)

    - The amount of moisture contained in a volume of air.

    also see:
    - The amount of moisture contained in a volume of air.

    also see:Observed Dew Point Temperature: indicates the amount of moisture in the air
    -
    - Read the first line of the second paragraph.
    - (however many there are)[/quote]
    -
    - Read the first line of the second paragraph.
    - (however many there are)[/quote]

    Last edited by Vern Heiler; 09-15-2009 at 06:40 PM. Reason: Link didn't take

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    Default Re: High Humidity with Heat Pump

    Vern, Vern, Vern,

    When are you ever going to learn?

    Now that you have progressed from crayons to reading THE FIRST LINE ... let's see if I can help you progress EVEN FURTHER in your endeavor of learning to read, so, with that being the intent, ...

    I am sure that you are good at drawing pictures and understanding them too, so, let us now READ ON TO THE FIRST LINE BELOW THE PICTURE.

    In fact, let us address the first paragraph below the picture one line at a time.

    Dew points indicate the amount moisture in the air. The higher the dew points, the higher the moisture content of the air at a given temperature. Dew point temperature is defined as the temperature to which the air would have to cool (at constant pressure and constant water vapor content) in order to reach saturation. A state of saturation exists when the air is holding the maximum amount of water vapor possible at the existing temperature and pressure.
    "Dew points indicate the amount moisture in the air."

    Okay, you have that down pretty good.

    "The higher the dew points, the higher the moisture content of the air at a given temperature."

    However, Vern, you did not read far enough " ... at a given temperature."

    Oh, wait, there IS another factor in dew point, isn't there? Dang, well I'll be! There it is, there is that thing called "temperature".

    "Dew point temperature is defined as the temperature to which the air would have to cool (at constant pressure and constant water vapor content) in order to reach saturation."

    Holy crap! There is that "temperature" word again: " ... the temperature to which the air would have to cool ... ", in fact, a CHANGE in "temperature".

    "A state of saturation exists when the air is holding the maximum amount of water vapor possible at the existing temperature and pressure."

    Dang! We just cannot get away from that "temperature" word, can we?: " ... at the existing temperature ... "

    Oh, lookee, there is also ANOTHER FACTOR ... "pressure".

    Now, Vern, keep reading and in the next paragraph down you will see "Therefore, if the air cools, ... "

    Dang! So not only does the "amount of moisture in the air" affect dew point, but the "temperature" also affects due point, as does "pressure".

    Now, Vern, please explain to me how ONLY "the amount of moisture in the air" affect the dew point?

    Jerry Peck, Construction / Litigation Consultant
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