Humidifier Games

[HoosierBuddy]

So....Not an issue...just a story and feel free to post if you have any thoughts on this.

Years ago, I put an Aprilaire 400 humidifier on my NG furnace. This is the "water saving" model which I bought after a lot of thought. The way it works is kind of unique. When there is a heat call and the humidistat is not satisfied then the water valve kicks open and water flows through a 1/4" line into a water diverter that creates a waterfall over a pad. The water runs down the pad into a sump. The sump has float switches that will eventually turn off the water when the sump is full. At that point, the hot air bypassed through the pad rapidly dries the pad and water is supposed to wick back up into the pad from the sump to keep it moist. Eventually the sump water level drops down, the float switch reports this and the water valve reopens.

Does it work? No not really. The pad doesn't wick water up out of the sump worth a darn. The sump remains full. The float switch is satisfied. The valve never opens to put more water on the pad.

Does it save water? Absolutely! It doesn't use a pint a day probably. But that's not a feature really, more of a design flaw.

So, I didn't worry about it until the wife started having repeated nose bleeds. Humidity in our bedroom in recent cold snaps hovered around 20%.

I bought the manual version of the Aprilaire 600 a couple of weeks ago. It installed right in the same hole that I took the 400 out of. The 600 is the traditional water guzzling unit. It doesn't have a sump. It doesn't have float switches. I wired it up so if there is a fan call, and the manual humidistat is not satisfied, it energizes the valve and runs water into the top of the humidifier pad until the fan call ends.

During the current cold snap humidity in our bedroom is hovering around 30% and no nosebleeds.

BUT....when you look at the clear tube leaving the humidifier during operation, it has a steady stream of water heading to the drain. The water/sewer rates in my town are horrendous. Our water/sewer is well over $100 every month.

So...I bought a 1/4" Control Needle valve off Amazon for $9 and have been "tuning" it so that I get some flow during a heat call into the drain, but maybe about 1/3 as much as I did with no control valve.

It seems to work. I'm not 100% sure yet...

I can report for sure that replacing the "water saver" humidifier with the standard type works a whole lot better. Probably not a surprise to anyone.

Phil

 

[PoorUB]

I used to sell HVAC equipment and that water saving 400 was a joke, even worse in hard water areas as the bottom part of the pad would just calcify from the hard water and do nothing. If they had added a small pump, or made the humidifier short and wide perhaps it would work, but the top 2/3rds of the pad never sees water until the pan needs a refill.

The 600 will do a much better job as you have found out, but a lot of water goes down the drain. You probably could have just used the 400 and ripped out the water level controls ant let it "over flow" down the drain and been happy with it.

The other answer is a steam humidifier. They don't use as much water as a bypass, but they use a fair amount of electricity and replacing the tank every year or two is a $100 deal. What *** comes down to is there is no free meal, they all have a cost to operate. A simple bypass like the 600 is probably the least money overall.

If it makes you feel better I have a 600 in my home.

 

[HoosierBuddy]

I used to sell HVAC equipment and that water saving 400 was a joke, even worse in hard water areas as the bottom part of the pad would just calcify from the hard water and do nothing. If they had added a small pump, or made the humidifier short and wide perhaps it would work, but the top 2/3rds of the pad never sees water until the pan needs a refill.

Great minds think alike. I considered using a condensate pump to pull from the sump and rewet the pad during heat calls....but then I saw the 600 was only about $150...so I just went that route.

Question: I have 2 of the Aprilaire 400 specific pads still (new in box). They are the same size as the 600 pads, but made out of a lighter material. I assume to make it wick better. Do you think I can use those in the 600?

 

[larry4406]

I have a cast iron pot that sits on the wood stove. It simmers all day that the wood stove runs. I fill it in the morning and in the evening. We run the wood stove 24/7 during the heating season.

We boil about 1.5 gallons a day. House humidity is in the 28-33% range during operation.

 

[PoorUB]

Great minds think alike. I considered using a condensate pump to pull from the sump and rewet the pad during heat calls....but then I saw the 600 was only about $150...so I just went that route.

Question: I have 2 of the Aprilaire 400 specific pads still (new in box). They are the same size as the 600 pads, but made out of a lighter material. I assume to make it wick better. Do you think I can use those in the 600?

Use them, I can not think of one reason not to.

 

[HoosierBuddy]

I have a cast iron pot that sits on the wood stove. It simmers all day that the wood stove runs. I fill it in the morning and in the evening. We run the wood stove 24/7 during the heating season.

We boil about 1.5 gallons a day. House humidity is in the 28-33% range during operation.

With my old (crappy) humidifier I was seeing 35% humidity in our kitchen when we had 20% upstairs. All that water boiling on the stove for dinner, coffee brewing, and steam coming off the dishwasher does make a tremendous difference.

As a data point, the Aprilaire 600 spec says it has a "Capacity of 17 gallons per day".

It'd be cool to know if that's what they say the pad can transfer to the air blowing into the house OR if they are saying if you let the valve run full blast for 24 hours, that's how much water it would use....because there is a tremendous difference.

Math time...relatively humid air at room temperature has about 10 grams of water per cubic meter or .0006 pounds per cubic foot. So, a 2500 square foot house with 8 feet ceilings would have about 1.5 gallons of water vapor at any one time. AHRAE says acceptable air quality should have .35 air changes per hour. Say is 32 outside with 50% humidity. That air is going to have about 1/3 the amount of water in it that you want in it. So, you need to add 1 gallon of water every time the air changes or .35 gallons per hour....which would be 8.4 gallons per day.

That's if it's 32 outside, 50% outdoor humidity, house the size shown, and your air turn over is at the ASHRAE standard. None of those are true, I'm sure....but kind of gives a feel for the size of the task.

PHil

 

[fitter30]

Any pad type humidifier that just runs water through it is self cleaning and pad replacement is once a year. Steam humidifiers sound good but when the furnace fan shuts off any water vapor condenses falls to bottom of duct rust the duct. The tihter the house the less evaporator water is needed to get to set point. Loose house never will get setpoin. RH goes from warmer area to cold. No vapor barrier in walls rh goes right through them. Chech with your electric company see if they offer a energy audit that include a blower door test.

 

[Sumboodie]

Sounds like an HRV is what you're needing.

 

[PoorUB]

Sounds like an HRV is what you're needing.

An HRV in the winter will lower the humidity in a home.