Whole House Humidifier

Discussion in 'HVAC Heating & Cooling' started by jdoll42, Mar 4, 2008.

  1. jdoll42

    jdoll42 Computer Systems Engineer

    Messages:
    68
    Location:
    In Illinois near St. Louis, MO
    We've got really low humidity in our house. It's been bad all winter. We purchased a cheap humidifier and have been running it at night in the bedroom while we sleep. It seems to be helping. However, I'd like to "fix" the low humidity throughout the entire 3000 sqft house. (I can't count how many times I've shocked the bejesus out of myself this winter, not to mention the dry eyes, bloody noses, etc...)

    Anyway, I'm thinking about putting a whole house humidifier on our heat pump. Anybody got any suggestions on brand or model? Any pros/cons for doing it this way? I feel comfortable installing one myself, but why do it at all if you aren't going to do it right? This seems like a good idea to me, but I want to make sure I'm not making a mistake I'll regret down the road.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    I thought someone else would chime in...

    I put in an April Aire whole house humidifier. They make numerous versions based on the size of the house. Mine is fairly small.

    One (sometimes optional) feature is the outdoor sensor that modulates the total house humidity based on the outside temperature. It also turns it off automatically if the temperature rises above 50-degrees. As the outside temperarture drops, you are more likely to get condensation on windows or walls where there is low circulation, and if you always maintain the same relative humidity, you could start to get mildew on the walls. Having the outside sensor means you rarely have to adjust the control once you've found your ideal setting.

    The things require periodic maintenance - changing the evaporation panel, cleaning out scale, and dust/dirt that may accumulate and let things grow. Depending on the type, this may only be an annual thing, but may require more frequent attension.

    Lots of companies make these things...April Aire has been around for awhile, and mine has been reliable. I have no experience with others...so can't steer you to alternatives.
  3. v10rick

    v10rick New Member

    Messages:
    11
    Installed a humidifier recently on our heat pump, with a propane furnace backup, and had problems.

    The solenoid that supplies water to the humidifier is 24V and there is no terminal in our HVAC system that will power this valve in both the heat pump and backup modes.

    Installed a sail switch in the return duct and used the power supply that is supplied with the humidifier as a fix. As long as there is air flow in the return duct the solenoid will operate.

    The down side of the HVAC humidifiers...unless the fan is running continuously it is difficult to control the humidity in your home. If the call for heat is infrequent the humidifier will not be effective.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    True...you need air movement. I have a variable speed air handler, and leave it running virturally all the time summer and winter. I was able to tap off the 24vac circuit in the air handler to power it without problems, but you may have to wire in a transformer. There may be some that use 110vac...never looked that far to find out. Unless it is calling for conditioning, my fan runs on speed 1 of 16...enough to stir things up, but the power requirement is low and, hopefully, life isn't too affected (it's something like 15-years old now).
  5. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT


    Install a steam humidifier..
  6. SteveW

    SteveW DIY Senior Member

    Messages:
    1,052
    Location:
    Omaha, NE
    I have a heat pump and it runs fairly often - certainly often enough to keep the RH reasonable.

    I switched from a General humidifier (similar in concept to Aprilaire - uses a pad that water runs over) to a Desert Spring unit I got at one of the big boxes.

    Main reason I switched was I got tired of
    1) buying a new media pad every year and
    2) watching all the wasted water (from flushing the pad) run down the drain.

    The Desert Spring does at least as good a job humidifying, wastes much less water, and nothing to replace.
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    Replacing a pad once a year is easier than soaking the thing in vinegar to clean IMHO, but that's your choice. The pads can be found for mine for about $5 each (more if you want an "official" pad). By running some of the water down the drain, it flushes the concentrated minerals, which extends the life of the pad.
  8. jdoll42

    jdoll42 Computer Systems Engineer

    Messages:
    68
    Location:
    In Illinois near St. Louis, MO
    Thanks for all the replies. I run my blower 24-7, so I'm not worried about kicking the humidifer on and off again. It is interesting to hear about the outside sensor. I'll have to see that the system I get has something like that. No sense in having condensation inside. I'd rather it be dry than grow mold.

    Also, I'm curious to learn more about the differences between the units with the replacable pads vs. the units with no consumable media. Would either setup be more or less prone to mold/mildew growth? We also have a lot of dissolved minerals in our water, so I'm concerned about buildup on the unit. Which way do you think I'd be better off?

    Regarding the water quality, is there some sort of filter I should use before the humidifier that would hlep protect against buildup? I don't have any water quality tests, but I'm guessing I might be able to get those from the water company if needed. I know our water isn't all that great just based off what our showerhead and sinks look like.
  9. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,824
    Location:
    New England
    Whether you use a steam unit, or an evaporation unit, the water in vapor form leaves all of the minerals behind, so a water softener might help...other than a reverse osmosis unit, filters won't remove them.

    A steam unit uses a fair amount of energy (relatively) to heat the water to boiling. Picture a tea kettle, eventually, the bottom gets full of minerals. On a pad, you throw it away and replace it. On the rotating disks, you have to clean it off, as you do with the steam units.

    A steam unit may end up being more sanitary since few things will live in boiling water. In the pour and drain pad units (like I have), the pad will gum up with dust if the air filter isn't kept clean, but that doesn't happen too often. You have no standing water, since anything that doesn't evaporate, runs down the drain (a possible drawback to some). those that keep a reservoir full can grow things.

    I'm not sure how many brands use an outside sensor, but it does work, and on the unit I got, it was standard. Some installers don't think much of them, but I think they just don't care for the additional time required to route the wire outside (the sensor is just a thermocouple - a little bump on the end of the wire).
  10. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT
    Honeywell makes a humidistat with an outdoor sensor...
    http://www.ontimemall.com/h1008a1008-humidistat.html
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