humidifier

mel rowe

I had a steam unit installed and almost had a heart attack when I saw the effect on my electric bill. It was costing me about $95 per month in electricity due to the high power requirement, running 24/7. In addition it was a constant problem to keep clean, and flooded twice in 2 1/2 years due to the float hanging up on lime buildup. I finally got fed up and ripped it out and installed an Aprilaire, which I heard about here, and it will evaporate about the same amount of water, even using room temperature air, since it uses a flow of hot water to help evaporation. FWIW.

humidifer

humidifier

looking for good humidifier.well water,. have to put on return. looking for the maintenece free one ,unlikely . had drum type other house .let me know

Ken D.

Rick

I like Aprilaire. Readily available parts, good performance, easy to service, verstile. Do not get the model (445) with the reservior. This goes for any brand. The water stagnates and gets moldy. You end up breathing the spores. The one time trickle through type is best. Several different models to chose from. Considerations are size of house, duct sizes and clearances. If there is no drain close by, you may need a seperate condensate pump. Be sure to put a damper in the crossover to the supply duct.

humidifer

thanks I installed a replacement furnace with humidifer and was april aire with big filter and piped to condensate pump .

Dave L_4

The best type of humdifiers on the market are steam Injection such as Nortec resdlux any flow through type are a distant second place.

Dave

Dave L_4

you didn't have a Nortec, you probably had a tray type one with a element that sits in stagnent water. The type Im talking about injects steam into the duct & will run you thousands of dollars installed (but it works).

Dave

mel rowe

That's correct, I did have a tray type steam humidifier and it's capacity was about 13 gal. of water per day, which was costing me about $95 per month. I would think that the power required to vaporize the same amount of water by electricity is not dependent upon the type of unit and therefore is very costly regardless. My Aprilaire 600 only cost me about $140 and I installed it myself. It vaporizes the same amount of water as the old steam unit and costs less than $10 per month to operate. FWIW

carol_3

Here in Colorado, where the air's really dry, a flow-through by-pass humidifier (April Aire type) usually can't really provide enough humidification. Besides the air being so dry, we have enough solar heat gain that the furnace oftendoesn't run much during the day, even this time of year. One of the drawbacks of that type humidifier is that it works only when there's hot air coming out of the furnace. Humidifier gallons per day (gpd) are based on the assumption of 140 degree air, which only an old furance will do. Lower air temps pick up even less humidity.

I've had a steam unit for more than five years and it works great. It's a Honeywell, heating element in a reservoir, self flushes every 12 hours to remove minerals. Costs $10-20 a month to run. If yours was running 24 hours a day and you didn't have a waterfall running down your windows, something was wrong.

Constantin

Is it perhaps a control problem?

I'm surprised the humidifier had to run 24/7... my installer put in a simple horse-hair humidistat for the humidifier (Nortec) and it seemed to work well enough... but not great. Sometimes, windows in the house would be covered in condensate.

This summer, I made the switch to an electronic humidistat from invensys (private-labeled under the brand name "Signaturestat" for Lennox) to run one zone of the AC and the humidifier from one thermostat/humidistat. I opted for the model that can accept temperature input from the outdoors and installed a external temp. sensor also.

While getting the right setting took a while (the dewpoint adjustment function is incredibly badly documented) I am now happy with the results and the Nortec runs very little. I imagine the run-time also has to do with other factors, i.e. the infiltration rate, the external RH, you desired indoor RH, etc.

Overall, I am very happy with the Nortec unit and like how it can be drained for cleaning, etc. For a project at work, I picked up a cheap "18 Gal/day whole-house" humidifier at HD and was amazed at just how much of the water was bypassing the filter element. More than 2/3 of the water literally went down the drain instead of being vaporized.

Never mind that the unit could not even come close to keeping up with the stated capacity. Perhaps under ideal conditions (i.e. very hot plenum air) it can...

Mike Lampkin_2

Residential Steam Humidifier

I have just installed the new "Elite" model from Generalaire and it is performing quite nicely.

mel rowe

Just curious. How many watts of power do these steam injection units require?

Mike Lampkin_2

Power Useage

The Elite model DS15 uses 1.86kw @ 110v.

Regards, Mike Lampkin

mel rowe

Just to clear up a few things about prior posts. The Aprilaire humidifier doesn't require hot air to work. It works just fine with room temperature air, because it uses a flow of hot water over the pad to provide the energy to evaporate the 12 gals. of water/day, comparable to the steam unit. The steam unit required 1500 watts of power to operate. At approx.$.11/Khr., this is $.165/operating hour just for the electricity. My old house requires about 12 gal. of water evaporation/day to keep the humidity at 29-35%, dependent upon the outside temp.. I have found this to be the same with three different humidifier systems I have used, without any condensing on my thermal windows. It just takes this much water vapor. With this operating cost per hour, you can see why I stated that the steam unit was so much more expensive to operate. And that does not even include the cost of filter replacement (requires a regular type filter plus a reverse osmosis type filter), at a cost of about $160 for two years usage. By comparison the Aprilaire unit costs me about $.04/hr. to operate, including the water flow and the cost to heat the water. And the filter pad costs about $15/year to replace. I think you'll find all this to be fairly accurate and you can see why I said the steam unit cost so much more to operate, not to mention the maintenance costs and problems I've had. FWIW

Ken D.

Steam Humidifiers

I admittedly have seen only a few steam injection humidifiers. The units I have seen all had severe calcium problems and customer complaints. Maintenance is an issue. As we usually see in this business. In our area, Aprilaire is the preferred type and brand. I have had no problems. They are not as effective with heat pumps.

Ken D.

Humidifiers

And There you have it. Good job Mel.

Ken D.

Constantin

I throttle the water supply valve to keep the wasted water to a minumum. Agreed, though it can be a drawback.

Ken D.

Hello Carol

If you didn't have a Honeywell, I'd wonder why. Good points.

Brad White

Steam Humidifiers

The kind I specify such as Nortec, Armstrong and Dri-Steem use resistance plates in a disposable cartridge. The water is boiled and what leaves to the airstream is practically pure vapor. What minerals are left behind are deposited on the resistance plates and/or settle to the bottom of the canister.

As mentioned, the canister is disposable and is a cost to be factored in with how hard your water is.

Agreed that without the disposable cartridge, (the straight electric boiler type) prime elements would be an unacceptable loss if limed-over.

John Ketterman

By my calculations, a 1500watt heating device would have to run all the time to provide the latent heat to evaporate 12 gallons per day. So your steam humidifier numbers are pretty good.

But if the Aprilaire uses only 25% of the energy, how can it make 12 gal evaporate? Well, a blower-driven humidifier is in every way the same as a desert cooler: it evaporates the water by stealing heat from the dry air. The humidified air is colder than the dry air. This is good for summer, but not good for winter. Your furnace or boiler has to run longer to compensate for the desert cooler you are running in your house. In other words your boiler provides the other 75% (1100 watts, which is about 1 therm per day).

On the other hand, the steam humidifier ADDS electric heat to the house because the steam is at 212F and must cool to 70F. So your steam humidifier reduces the load on the furnace by about 0.1 therm/day.

You didn't account for any of that, did you? Of course, gas heat is cheaper than electric heat, but it's not free!

Calculation notes:
Latent heat of water=22.6*10^5 Joules/kg.
1kg=~2.2lb.
1 gal=~10 lb.
1BTU=~1000J.
1 therm = 10^5 BTU.
Heat capacity of water vapor=~2000J/kg/oC.

Mike Lampkin_2

Aprilaire specs

Hi Mel,

The Aprilaire model 600 shows an evaporation rate of .7gph and a water feed flow of 3gph through the pad, but the specs don't show what the actual air and water temperatures should be to give that .7gph evaporation rate. Can you let me know what these values are.Thanks.

carol_3

yes, essential info.

mel rowe

My house has a large air handler in the attic and related ductwork that was previously installed to provide for air conditioning. I added a small air handler (about 650 cu.ft./min.) in the basement and for the humidification season, the air flow is reversed. To answer questions, the air temp. is just room temp., which is about 70F. The temp. of the 3 gph water flowing to the Aprilaire is about 140F, which I learned on the Wall is the right level to maintain in a water heater. The reason I bought the Aprilaire 600 humidifier is it was the only Company that would assure me that I could get the amount of vaporization I needed with room temp. air, since the energy required was provided by the flow of hot water across the evaporation pad. In my prior calculations I accounted for the water cost as well as the gas required to heat the water from 50F to 140F. Of course my big savings are because of the operating cost differential of $.12/hr., running basically 24/7. If only an 8/7 operation was required, of course the total savings would not be huge. But then why would you need such a large capacity steam unit? And by the way, I forgot to mention the large difference in initial cost of the two systems. The least cost steam steam I know of (reservoir type) costs over $500 for the hardware alone. My Aprilaire costs about $140, so as soon as I confirmed it would do the job, it was an easy decision to changeover, and cost was recovered in just a couple of months. As you can tell I am pleased with the results and the anticipation of much less problems/maintenance, so I thought I would try to provide some actual results, in return for all the great help I have gotten here. Cheers.

John Ketterman

> In my prior calculations I

> accounted for the water cost as well as the gas

> required to heat the water from 50F to 140F.


This is actually a rather small cost (the latent heat of water is much larger than its specific heat).

The big missing factor is the hidden cost (extra load on your heating system when using fan-forced humidifier aka desert cooler), as I explained in my previous post.

Also, as others are pointing out, you don't actually know how much humidification you are getting. Manufacturers' claims are often wildly inflated, especially when they cannot be easily tested.

mel rowe

You're right that I haven't accounted for that factor, although I seriously doubt that it will affect my conclusions. However, I will check the air temp before and after the humidifier as soon as I can get an appropriate measure and post the data for you. You are also right that I cannot give you a precise no. of gallons of water actually being evaporated per day by the Aprilaire; however I do know empirically that it is providing the same level of humidity as the previous steam unit, so it's close enough to the Mfgr.'s claim that I am satisfied.

Mike Lampkin_2

Evaporation rates

Hi Carol,

Do you know of any companies that publish charts or graphs of air temperature versus water temperature to determine the evaporation rate of water through a flow-thru humidifier,such as the Aprilaire model? When I checked with Tech support at Aprilaire, I was told that 140°F water feed temperature to the flow-thru pad should be able to humidify 70°F room air through the air handler. The only way that I know of to verify the evaporation rate would be to measure the incoming water against the water heading out to the drain.
Regards.

Dave_23

Add on to Spacepak

Would it be practical to add a steam injection humidifer to an attic-mounted Spacepak air conditioning system? I'd like to humidify my home, which is heated with steam rads/boiler. I have central air via a spacepak. Thoughts?

Constantin

I'd contact the mfgr...

I see no reason why not, but presumably the OEM has a preferred way of doing things. Our house is heated via RFH, so the humidifier needs to trigger the AC systems' air handler's ECM motor into action. IIRC, humidistats have 2 contacts for that very purpose, one to trigger the fan, the other to trigger the humidifier.

Our humidification system has 2 interlocks, one to prevent the humidifier from running if there is no air flow through the AH (pressure switch), a second one to stop the humidifier if the RH in the duct work exceeds a certain set point. Considering how cool the air in our ductwork typically is during the winter (~70°F) condensation is definitely a concern. So far, everything seems to be working fine.

mel rowe

There have been some very good questions raised about my Aprilaire 600 humidifier recommendation over the reservoir type steam unit I ripped out and replaced. I have gathered some more info and will do my best to clarify further why I think the Aprilaire was a better choice for me. Please understand that I have no axe to grind either way, I'm only providing data and observations from my personal experience to date. A good question was raised regarding whether my operating cost comparison was overlooking costs related to the boiler heat required to compensate for the lowered air temperature as a result of giving up the energy necessary to vaporize the .5 gal. of water per hour, with the Aprilaire. I had assumed .5 gal. in order to be conservative and to make it comparable to my old steam unit. Although the necessary evaporative energy is provided by the flow of hot water through the evap. pad , and was included in my calculation of costs, reevaluation confirmed that I had underestimated that element. By collecting the water from the drain, I found that I had misunderstood the amount of water flow. Instead of 3 gal/hr., it is more like 4.5 gal. The net effect of this would be to increase the operating costs for the Aprilaire to $.06 per hour, compared to my calculation of $.165 per hour for the steam unit I previously had. I also did some testing that confirmed that the energy required to evaporate .5 gal/hr. is adequately provided by the hot water flow, because I checked air temp. before and after the humidifier. Results were 69F before and slightly more than 70F downstream. In addition, the temperature of the overflow water at the drain was approximately 65 degrees, so most all the heat energy from the hot water is being provided to the air flowing through the pad. Feel free to potshot any of this, as there's always room for error or misunderstanding; however, I feel that with the order of magnitude difference in operating costs, the overall conclusion is unlikely to change. This is especially true if you also consider the initial hardware cost difference of $500+ vs. $140, and the annual maintenance costs for filters, which is approx. $80 vs. $15. Cheers.

Eric_25

We have done this

We have added a steam injection humidifier to a SpacePak system. The difference to yours was (i am ASSuming)we had installed a hot water coil to provide heat to the space as well. The down side to your application would be that without warming the discharge air the home would be very drafty with the HV system running moving room temperature air. If this system is in the attic in an area that sees freezing temps you would also run the risk of freezing the unit or condensing the water vapors in the ductwork and freezing them.

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