Whole house humidifier not through HVAC system?


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Old 10-11-15, 08:29 PM
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Whole house humidifier not through HVAC system?

Hi All,

We have baseboard/hot water heat and two central a/c units (upstairs and downstairs), and we are thinking of installing a whole house humidifier. The only problem is we have no idea if the type we would need is even made. Are there any units that don't need to be attached to a duct system? I seem to remember some sort of humidifier that you just place in a central area and moisture somehow gets to all areas of the house. Alternatively, are there any units that can be used with a central A/C unit only? If so, can it attach to both my a/c systems so that I can humidify both upstairs and downstairs at the same time?

One of the systems was installed before we moved in, so I don't know much about it. However, we installed the downstairs unit, which is a Carrier dual speed condensing unit and a Carrier indoor variable speed fan coil, with a Carrier "Edge" dual stage digital thermostat and an Aprilaire model 2210 "Hepa-style" high-efficiency purifier. I'm not quite sure what any of this means, but hopefully it means something to someone! However, I do know that it measures humidity and I can set the target/desired humidity level, and the unit can achieve it (down to 46%, I think) separately from achieving any desired temperature.

Any thoughts, ideas or advice would be great appreciated. Thanks!
 
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Old 10-11-15, 08:55 PM
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I read your other post about running the fans in the winter to circulate the warm air. You would need to run them if you are considering central humidification. There are two problems here.

1- You would need two units, one for each system, to humidify the whole house.
2- Central humidifiers don't add much humidity to cool air. They work best with warm/hot air like from a furnace.

You may want to consider a free standing humidifier to humidify the lower level. They are not without some routine maintenance. They require the water reservoir to be refilled and kept clean.

amazon/Whole-House-Console-Style-Evaporative-Humidifier
 
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Old 10-11-15, 09:13 PM
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Thanks for the info. I've never seen "portable" whole house humidifiers, so that might be the way to go. At ~$150 each, wouldn't break the bank to get 2 of them.

Thanks again!
 
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Old 10-11-15, 09:29 PM
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When you go to that link..... look directly above the product description and you'll see "whole house humidifiers." If you click on that you'll see there are many to choose from. Home improvement stores also carry them.
 
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Old 10-11-15, 09:37 PM
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The pros will have to educate me as well, but I'm not sure what that unit is when you can set the low humidity level at "down to 46%". That sounds like a dehumidification setting for an air conditioner, not heat. Education welcome.

However, my reason for posting is to explain why you might be experiencing dry air during the winter. Cold outside air is very dry once it is heated to the desired 70°. Since all home have air leaks we are constantly having to heat the infiltration and the result is dry air. The moisture generated by human activity which should be more than enough has leaked out. The typical air leakage rate is rather high with all of the air in a home being replaced every 2 to 3 hours. That's where a humidifier system has to work hard to keep up as all of the moisture it introduces keeps escaping.

Solution, seal the air leaks and the humidity levels will go up naturally. And the heating bills will go down along with a more comfortable home.

More details if you are interested.

Bud
 
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Old 10-11-15, 10:03 PM
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Just to interject..... the OP's system can be set to dehumidify by setting a humidity set point. That won't be of help in the winter. Also.... you won't to need add as much humidity to the house with baseboard heat. It's typically a furnace that dries the air out excessively.
 
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Old 10-18-15, 07:35 PM
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Thanks for the advice, everyone.

Bud - we had an energy audit a few years ago, which resulted in us doing lots of air leak improvements (low air flow high hats, a cap on the attic door, lots of caulking, etc.). Blower door test before and after showed a huge improvement. With a very high efficiency boiler, I now pay about the same in utilities each month for my ~3200 sq. foot house as my father-in-law in a very nearby town does for his ~2200 sq. foot house. Also, 46% RH setting is on the a/c system, not on the heating system; sorry for any confusion.

Thanks again.
 
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Old 10-19-15, 06:52 AM
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If you don't mind me asking, what was their after air sealing blower number and did the work/testing result in an air exchange system, an HRV, ERV, or bathroom fan on a timer?

Most project like that only hit the obvious spots. The real world test, no instruments needed, is the condensation on your windows on the coldest nights. It often appears on windows when the curtains are closed. If you are not seeing that, then more air sealing. The other real world observation is, low humidity in the winter.

If the air sealing was very good and you are still experiencing low humidity, then there is a reason other than not adding enough moisture. Forced air ducts often leak or are not balanced properly causing pressure differences that increase the air exchange.

I have worked on several tight homes that have to run a dehumidifier during the winter.

Bud
 
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Old 10-24-15, 09:14 PM
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We had the energy audit and work done a few years ago, so I don't remember the numbers. But it was through NJ's state energy division, and my level of rebate was based on the overall improvement in efficiency - I was granted the highest level of rebate. We ended up installing a high efficiency boiler (Triangle Tube, 96.0 AFUE) with an indirect fired hot water tank, along with all the air sealing and low air flow light canisters. Also put a covering on the attic door to stop air flow up. No air exchange system of any kind from that, although a friend and I installed a whole house fan a year later (QuietCool CL-6400, which we love) - but I don't think that's what you meant (right?).

When temperatures outside are really, really cold, I do remember seeing condensation on our skylights; not sure about the windows themselves, I'll have to remember to check in a month or two when temps really drop around here. I understand about forced air ducts leaking, but would that be a problem for me if our heat is baseboard-only, and I close the a/c grates in each room (and also cover them with an insulating bubble-wrap type of thing)?

Thanks again.
 
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Old 10-25-15, 03:23 AM
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The target number they often try to hit is 0.35 air changes per hour (ACH). At that level they don't have to install an air change function. Unfortunately, they will overlook much of the lesser more difficult air leakage and meet that number by addressing only the easy work. The skylight showing some condensation would be correct as they usually are not as high performance.

So, what does this mean for needing/wanting to add a humidifier? When inside air leaks out it must be replaced by outside air leaking back in. When that outside air is warmed up to the desired temp, its RH level drops significantly. Since NJ is not noted for extremely cold temps or dry air, have you monitored the RH during the cold season? Or are you relying on general comfort indications? Having actual RH numbers and the accompanying temperature would help.

Pick up an inexpensive RH meter and collect some numbers (remember to record the temp as well). If comfort is your concern, with most of the potential air sealing having been done, then a free standing humidifier may be necessary.

Bud
 
 

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