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  1. #1
    Join Date
    Jan 2008
    Location
    Lehighton, Pa.
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    178

    Bypass humidifier question

    My dealer will be installing a bypass humidifier on my Infinity furnace. Is it better to use hot or cold water for the supply, and why?

  2. #2
    Join Date
    Aug 2001
    Location
    Pavilion, NY
    Posts
    2,153
    Hot water. The evaporation rate is higher.
    ...

  3. #3
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    Oct 2010
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    Anderson, South Carolina, United States
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    7,102
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  4. #4
    Join Date
    Dec 2010
    Location
    The Quad-Cities area (midwest).
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    2,702
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  5. #5
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    Feb 2010
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    In a boiler room
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  6. #6
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,470
    Humidifiers use 3-4 gals. of water per hour. Three gals of hot water cost $.07 at $.10 per kw. Could easily be $1-2 per day. A heater set at 130^F with a 20 ft of copper tube will deliver water 20-30^F below the supply temp. Assuming 100^F water into the humidifier, evaporating 1 lb. of water uses 1050 btus. Most homes may use 4 lbs. of moisture per hour. This is 4,000 btus per hour. 3 gals. of water at 100^F down to 70^F is only 700 btus. and cost $.70. The other 3200 btus must come from the furnace with much cheaper heat source, usually less than half the cost. Possibily with natural gas water heater, the hot water supply is more reasonable.
    I suggest using cold water and increasing the air flow of the by-pass humidifier by adding a 200 cfm duct fan to increase the evaporation rate of slow furnace.
    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"

  7. #7
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420
    Hot water because the heat pump's supply temperature isn't what a gas furnaces is. It will work either way though.
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  8. #8
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,171
    Hot.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  9. #9
    Join Date
    Nov 2006
    Location
    Athens, Ohio
    Posts
    1,834
    Several years ago at a seminar hosted by Skuttle, the rep said cold water is better. He was a technical rep, not a sales rep. His presentation and answers were very knowledgeable.

  10. #10
    Join Date
    Apr 2003
    Location
    Maple Grove, MN
    Posts
    1,304
    In theory, hot water will evaporate better and you will use less water, but in reality it won't matter much, since either one will be at about room temperature by the time it makes it from your plumbing, through the little 1/8" tubing, and into your humidifier to be evaporated.

    If it isn't too late, I would check into having a fan powered humidifier installed instead. They work a lot better and use less water, and are usually easier to install.

  11. #11
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,470
    Quote Originally Posted by ammoniadog View Post
    In theory, hot water will evaporate better and you will use less water, but in reality it won't matter much, since either one will be at about room temperature by the time it makes it from your plumbing, through the little 1/8" tubing, and into your humidifier to be evaporated.

    If it isn't too late, I would check into having a fan powered humidifier installed instead. They work a lot better and use less water, and are usually easier to install.
    Refreshing! Also the little bit of heat left is nothing compared to the amount of heat to evaporate water. It's all about air velocity through the pad. VS fans do not get enough air through a by pass humidifier. A 6" duct fan in the bypass duct also does a great job.
    3 gals per hour of hot water counts up and cost a lot of $.
    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"

  12. #12
    Join Date
    May 2008
    Location
    Missouri
    Posts
    3,543
    Totally agree with bear. Use cold water as hot is simply too expensive for the minimal increase in humidity. If your unit is variable, just add the booster to the bypass pipe. We seldom sell powered humidifiers as they are more complex and fail more often. Non-powered bypass are simple and work fine, and have for years and years!!! Just make sure and change the pad yearly!!

  13. #13
    Join Date
    Jan 2008
    Location
    Lehighton, Pa.
    Posts
    178
    OK, 6 votes for hot and 4 for cold. Now I'm really baffled. While everyone has opinions, who should I, being the novice listen to?

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