Which Humidifier When No Nearby Floor Drain?

alwaysfixinJanuary 9, 2011

We want to install a whole house humidifier. However, the location at our NG furnace does not have a drain nearby, though it does have access to water line. DH said installation would be easy, no problems with location/space. I am looking at Aprilaire, mainly cause it's the name I associate when I think of humidifiers. I did a search for threads here about humidifiers, and there weren't too many, but a couple did mention Honeywell. When I looked at the Aprilaire website, the Aprilaire 400 seemed to be the only model that didn't need a drain nearby, but I am wondering if it functions as well as their other models.

Here are all the stats I could think of:

Location - suburbs of Chicago. TV weatherman said last night that weather conditions (dry and single-digits) meant inside home humidity typically about 8% in January.

Size - 2-story, 1700 s.f.

Tightness - DH just insulated all the outside walls, and it's like night and day compared to how drafty it was before. It's a '50's house, so it's still not super tight.

Water hardness - just slightly hard water, not hard enough to need water softening.

Somebody told me to get the Aprilaire 700 cause it's the one with the fan, and the fan is important, though I am not sure why. But the 700 seems to need a drain nearby. The 400 doesn't have a fan, but doesn't need a drain. DH will do the installation (he is very good, he just finished our entire kitchen himself except for the granite, so I am not worried about installation). I'm in charge of purchasing, so I am looking forward to advice from you experts as to brand and model. TIA.

Aprilaire 400 that doesn't need a drain nearby

Aprilaire 700 that has a fan

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You didn't mention anything about your current 'heating system': don't know how long it will be before you replace that.

What I'm getting at, is that whenever you do replace it, it will likely be a high efficiency unit(> 90% efficiency), which will require a condensate drain. If it is located in a basement or utility room where you do your laundry, the condensate can be drained via a wash tub or standpipe. Worst case, you may have to buy a condensate pump (probably less than $100 at a home center).

If you go this route, make sure that the pump has an overflow safety switch, which should be wired through the furnace's 24v supply. This way, if the pump fails (or stops for some reason), you will not get a flood.

Another thing to consider: Units without a fan other than a drum type (not too many of those around), utilize a bypass duct to draw hot air through the wet medium, then back into the return air stream. This amount of air is 'stolen' from the supply air. With a 1, 2, or 3 stage furnace, it's not a problem. If you are considering a modulating furnace, which runs mostly at relatively low fan speeds, it could be a problem.

You might want to hook it up to the hot water supply.

Good luck.


    Bookmark   January 9, 2011 at 4:37PM
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Thank you for your reply. The furnace was replaced about 4-5 years ago, so there won't be another replacement any time soon. It is not a modulating furnace. There doesn't seem to be a condensate drain. Our washing machine, while in the basement, is quite far from the furnace.

    Bookmark   January 9, 2011 at 4:47PM
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I know that Aprilaire's website says that it utilizes 100% of the supplied water, but the installation manual shows that the unit has a 'safety' overflow drain connection at the bottom.


Choose whichever unit you feel is best, based on its specifications and your needs. I'm not familiar with the model 400, but the idea of not having a drain makes me nervous. I seem to recall reading posts on another forum, where the PROs didn't think too highly of it.

Living in a cold winter climate, when my HE furnace was installed, I specified that the condensate be pumped laterally about 20 feet, then up about 20 feet to a first floor laundry room, to avoid freezing problems.

A little giant pump (probably closer to $50, could easily pump your waste water up to the ceiling via vinyl tubing, around the perimeter, or directly to your tub.


    Bookmark   January 9, 2011 at 5:29PM
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Oops, just spoke to DH. We DO have a pump to pump the condensate from the furnace. There is a hose that takes that water 30' (along the ceiling) to the laundry sink. The pump does not have a safety shutoff. It's just a small pump. The contractor who installed the furnace didn't even want to add the pump, but DH insisted, and the contractor gave us a basic pump for the condensate. So, are you saying we could tap into that pump and hose to add the humidifier water drainage? How do we know if it's too much water for the pump to handle? Is there a formula to size the pump? Do we need to buy a more powerful pump?

    Bookmark   January 9, 2011 at 8:40PM
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Yes, it is possible to dump the humidifier's waste to the pump.

It would be helpful if you indicated the make and model # of your furnace. Also, any information on the pump if available.

Actually,household condensate pumps are small in size. At some point, ANY condensate pump will be full and switch on.
There is a float inside the pump which activates it, when in the 'up' position. Should it become stuck by crud or whatever, the pump will eventually overflow.

Check to see if there are 2 wires on the pump that are capped or taped, with no connection. A pump without a safety switch, is an accident waiting to happen. Think about this: If your furnace is producing condensate, and your pump becomes stuck (with no humidifier adding water), it will overflow.


    Bookmark   January 10, 2011 at 7:09AM
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The AprilAire 400 I had installed a couple of weeks ago seems to be working great. It is in an attic unit, so there wasn't a possibility of a drain.

The humidity is now consistent at 40% which is where I have it set. I have bought a couple of extra "water panels" because they recommend changes twice during the heating season.

    Bookmark   January 11, 2011 at 8:35PM
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I would run both to the pump. It might be a good idea to eventually upgrade to a pump with the safety overflow switch. I would also at that time add a switch for summer and winter that would make use of the overflow protection in summer and winter or look for a unit with two switches if they exist.

    Bookmark   January 16, 2011 at 6:30PM
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I am just a dummy, but it seems to me that running a total-water-use humidifier with hard water would be difficult. Maybe Aprilaire will tell you how it does not get limed-up quickly, but I don't see how it won't. With a system that flushes itself, it will be, at least to some extent, self-cleaning. Using the hot water supply will probably work better because some of the minerals have already been precipitated.

    Bookmark   January 18, 2011 at 3:33PM
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Nice response veesubotee. I agree with it completely. Thanks!!!

    Bookmark   March 9, 2012 at 1:44AM
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