Evaporative vs Steam Humidifier?
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  1. #1
    Join Date
    Nov 2002
    Posts
    25

    Evaporative vs Steam Humidifier?

    In a dry climate like Colorado - are there any downsides to a steam system (like the Honeywell model)?

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,232
    All electric humidiifers use 1 kw to evaporate 3 lbs. of water. This is usually much more expensive than using the heat of a gas furnace or heat pump by a factor of 3. First thing is to tighten up the air leaks. 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"

  3. #3
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,829
    How much humidity you need to add to your home is the first question that needs to be answered. Please know that the need for the addition of water to the indoor atmospher of your home is greatly affected by the rate that warm air escapes and fresh outdoor air enters. That's referred to as the 'leak rate' of the home. The ideal rate varies but is generally somewhere between 7 and 11 air exchanges per day. A blower door test can determine the actual leak rate of your home.

    A standard humidifier attached to a ducted heating system uses the heat of the heater to evaporate water off an evaporator pad as the most common type. Since the air passing through the humidifier pad is the same air that's in the rooms of your home, the drier the air, the faster the water evaporates. The downside to any system humidifier BTW is that it only runs when the heating equipment is on. Some systems can trigger the blower to operate when the humidity is low but the blower is circulating room temperature air during the heater 'dwell' cycles and so the amount of water that evaporates is greatly reduced. But when you have a steam humdifier, it has its own heater and therefore can put a lot more moisture into the air. So if you home is very loose or very large of if there's someone in the home who's very sensitive to driness, then a steam humidifier might be the answer. Because it has its own heater built in, it can supply the same amount of water during a heater 'dwell' cycle as it could with the heater running. As to negatives, any humidifier should be properly sized for the home and humidity levels should always be kept at a healthy level but not at a high enough level to encourage the growth of molds or mildew. For most homes that's about 45% relative humidity in the winter and about 50% in the summer.
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  4. #4
    Join Date
    Nov 2002
    Posts
    25
    Thanks for the detailed response. We're at about 3000 sq ft, and currently have a standard evaporative/passive blowby system installed on the return, ducted to the supply side. It's 15 years old, and the main problem is the unit has a water trough at the top which is supposed to distribute water evenly down to the evap pad, but it doesn't at all - it drips to one side so only part of the pad gets wet, and thus very little humidification is taking place. We've had the unit removed and reinstalled (checking for level), cleaned the trough with CLR... nothing has worked and being in Colorado without the unit functioning we're at like 19&#37; which is uncomfortable and terrible for our hardwood floors!

    I'd rather have a high-performance unit as our furnace is quite efficient and doesn't run very long to get us up to temperature (meaning the humidifier has less time to do it's job). I have been looking at the Aprilaire 700 - price is affordable ($200) and highly rated. I've probable been turned off to steam in my situation, if only because it would require removing and undoing all changes from my current system (steam unit must be mounted on supply side, and must use cold water instead of hot)

  5. #5
    Join Date
    Nov 2008
    Posts
    14
    Based on my own experience, I suggest that you get the honeywell TrueSTEAM HM512, 12 GPD.

    My house is 3200 sqft and I have the above steam humidifier with the Honeywell VP IAQ t-stat. I can set the desired indoor RH at 35%, 40% or even 45% and the system easily reaches the set point with a swing of 1% below/above the set point. Right now 45% would cause some condesation on the second floor bedroom windows (-5C outdoor night time, eastern Ontario, Canada) so I set it to 40%.

    To install the TrueSTEAM you only needs a 1.75" hole on the supply plenum, you can even buy the remote install kit to install the humidifier on the wall near the furnace and the hole required to insert the steam hose would only need to be 1" - That's my current setup as I don't have enough top/bottom clearance to put it directly on the supply plenum.

  6. #6
    Join Date
    Dec 2005
    Location
    Virginia Beach, Va.
    Posts
    250
    Evaporative or Steam Humidifier
    From working the service side of this business, I would say witch one, would you be willing to eat your lunch out of after a year or two of service. The nose is connected to the mouth & you breathe that filth. Evaporative can look real nasty inside!

  7. #7
    Join Date
    Nov 2002
    Posts
    25
    I'm definitely up for the Honeywell Steam units - my problem is that my house is too big for them. I've got currently 2,300 sq ft plus another 1,000 in an unfinished basement. The HM506 is only rated to a MAX of 2,000 sq ft in a very tight house, and the HM509 to 2,500. I'd guess my home is "average", so we're down to 1,500 and 1,800 sq ft respectively. I would really hate life if I spent MORE on a steam unit only to have it work less effectively than a cheaper evap unit, ya know? The Aprilaire 700 is rated to 4,000 sq ft and costs 1/3 less. (If I went with the HM512 as offered above, the price skyrockets to fully DOUBLE the cost of the Aprilaire unit!)

    So my question is - are the Honeywell Steam units under-rated, or is it pretty accurate? If it's accurate, I guess I'm going to have to stick with an evap unit and changing filters every year.

    Finally, THANK YOU for your help in this matter. It is VERY appreciated!

  8. #8
    Join Date
    Dec 2005
    Location
    Virginia Beach, Va.
    Posts
    250
    Get straight from the horses mouth

    http://www.skuttle.com/faq.html

  9. #9
    Join Date
    Nov 2008
    Posts
    14
    I'm in cold Canada and my house is 3200 plus 1500 unfinished but conditioned basement, new construction. I'm very happy with the HM512 so far like I said in my previous post. Keep in mind that, athough the house is pretty air tight, I'm running my HRV 8 hours per day (20/40 control) @ 100 - 110 CFM. Is its performance/capacity underrated? You figure it out yourself

    I had bypass humidifier in my old previous house and now I'll say that I will never go back to any manufacturer's any verion of bypass/flowthrough type of humidifiers. I paid way much more then you guys would because, not only I had to buy it on ebay and paid with weaker CDN$ at the rate of 0.84, but also had to pay UPS and Canadian customs CDN$260.00 extra.

    This is just an homeowner's experience so take it for what it deserves and good luck.

  10. #10
    Join Date
    Dec 2006
    Posts
    32

    randyl712...

    check out my responses to another thread here in the past couple of days about the Truesteam. I provided a link that might be helpful...

  11. #11
    Join Date
    Nov 2007
    Location
    Rochester, MN
    Posts
    80
    Quote Originally Posted by Kindger View Post
    I'm in cold Canada and my house is 3200 plus 1500 unfinished but conditioned basement, new construction. I'm very happy with the HM512 so far like I said in my previous post. Keep in mind that, athough the house is pretty air tight, I'm running my HRV 8 hours per day (20/40 control) @ 100 - 110 CFM. Is its performance/capacity underrated? You figure it out yourself

    I had bypass humidifier in my old previous house and now I'll say that I will never go back to any manufacturer's any verion of bypass/flowthrough type of humidifiers. I paid way much more then you guys would because, not only I had to buy it on ebay and paid with weaker CDN$ at the rate of 0.84, but also had to pay UPS and Canadian customs CDN$260.00 extra.

    This is just an homeowner's experience so take it for what it deserves and good luck.
    I have a tight 4000 sq foot 2004 construction 20/40 100-110 CFM on my air exchanger, and after having a blower door test done found out that it was way to many air exchanges per day. I expect you have the same problem and could save some energy by not running your air exchanger as much and thus not needing your humidifier as much. My plan is to scrap the wall mount that came with the air exchanger. I'm going to connect the air exchanger to my IAQ system which runs my dual zone heating and air condtioning. This will allow me to run the HRV at any number of minutes per hour that I like.
    -D in MN

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,630
    Probably just need a new trough.
    And to have your current humidifier hooked up to teh hot water, and rewired that it and the furnace blower runs anytime the humidity is low.
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  13. #13
    Join Date
    Dec 2007
    Location
    Cedar Grove, Wi-Sheboygan
    Posts
    1,582
    Yep thats the way I have my humidifer wired up with my fan since I run my fan 24/7 on low speed so when theres a need for more humidification the humidifer will run as needed since the fan is already running, which you may want to consider changing your furnace to if your not already running your furnace blower 24/7 as it helps keep the house at a more even temps thru out the home and with the humidifer wired into the blower will turn on when ever there a need for more humidity, it works really nice. Also think of this, if your not running your blower 24/7 and when theres a call for humidity, what happens to the humidity after there has been a call for it ? it's not move thru the home if the blower is not running....Try having your blower running 24/7 with the humifier wired into the blower motor and then check back here with your results as I think your going to find your able to keep the home on a more comfortable level then how you currently have things set-up. I'm not sure myself if I am sold on those Truesteam set-ups myself as I have always used a AprileAire 700 or those type of hunifiers since I have been a home owner.

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