house heater and humidifier question
 

Every question I ask here gets answered magically, and there seems to be an expert or 3 here for just about everything so I'll try it once again. :)

I want to have humidifier installed for the house. I will hire someone to do that. I'm not handy enough.

The house is a newly built 2 floor 3000 square foot house with 2 zones. And we have one forced-air heater in the basement heating the first floor and another in the attic heating the upstairs.

One contractor that we spoke with said that it is not possible to put the humidifier upstairs because the water pipe may freeze. Furthermore, he said that I do not need it upstairs, since the humidifier connected to the downstairs system will humidify the entire house.

So my questions are:

What is a healthy humidity level? (The contractor said the humidifier can do 40%. Is that high enough?)

Will having the humidifier downstairs only be sufficient for the entire house? (The contractor said that the heat will carry the moisture rich air up. I am not clear on how that will work. I'm afraid that the humidity downstairs will end up being higher than upstairs.)

Thanks for your input.

-alkaloid

It sounds like we have opposite problems. I just bought another de-humidifier for our basement and it's default setting is 40% which is comfortable for us. If I turn it down to 35% we start to get static buildup from walking around on the carpet. If you turn it down to 30% it runs continuosly, which sounds like the level of humidity that you have.
Hopefully someone else can answer your second question.

Usually the target "relative humidity" level is considered to be 45-55%. As "relative humidity" increases, the amount of "latent heat" in the air increases causing us (humanoids) to feel warmer. Heat tape added to water lines would prevent any freezing of the pipes. However, not enough information is provided to truly analyze your diliema. What type of heating is provided (gas, strip electric, heat pump, etc.) and how much air exchange is provided between the upper and lower systems.

Also...are we talking about adding "latent heat" putting moisture in the air.....or about (de-humifying) removing moisture from the air????

Thanks for your help offrapel and vogad.

I want to increase relative humidity of the house in wintertime. The heat is gas furnace that heats air and forces it throughout the house. The heating people can install those moisture injector to the duct.

About the level of air exchange, middle 1/3 of the house is open between the first and second level, but the air ducts are not connected between floors. I don't know what kind of air exchange occur there. There is no active exchange but there is a large connected area.

I've heard 40% percent quoted everywhere, but I prefer a slightly higher level (at least 50%) and I can deal with the occasionally wet window

If your attic is cold - insulation in floor not roof - then the unit or water supply or drain tube would freeze. Try the regular unit in basement one and it will probably work fine. If it doesn't then perhaps you might consider ditching (getting rid of) the entire unit in the attic. Your furnace and AC unit could very well supply your upstairs if you made it a third zone. If you can get a supply duct up there to feed the existing duct work then you might consider it. Depending on your exact situation, I might be wrong - but I have seen these setups, mostly down south and I don't like those attic units. Zones can easily multiply the effective sq. ft. coverage of one system. FYI I don't bother with measuring RHumidity. My house if well insulated and I figure that the furnace doesn't come on enough to get over 40% or get to dangerous levels. If you are getting condensation and too much moisture then turn it down. Most humidistats that come with the units are rudimentary anyway. You would have to pay extra for a good one to tell you exact hum levels. Besides, the target rhum. level changes by the minute depending on outside temp and hum levels. Don't get too caught up in exactly what % you are at. My humidifier makes an incredible difference in comfort in the winter. No dry hands or throat, etc. etc.