Humidifier Question

[usernametaken]

In my last house, I had a whole house steam humidifier on the the gas furnace that worked nicely. However, it had blower activation which wouldn't be compatible with my Max Caddy wood furnace since it's an uncontrolled heat source. So, I was thinking of dumbing it down some and just getting a manual Aprilaire 700M. It would only come on when the blower runs. I talked with PSG about it and they didn't recommend a humidifier on the plenum (the only area of my ductwork that is large enough to accommodate the 700M) since moisture could rust the heat exchangers thus ending my warranty. However, a call to Aprilaire's tech line got me different info. They said that unless the unit failed, it would not add any moisture to the plenum/heat exchangers unless the blower was running and therefor carrying the moist air away from the exchangers.

Has anyone here ever added a whole house humidifier to their wood furnace? Any perspective or experiences would be appreciated...

 

[Bad LP]

Can't you use the ultrasonic model with the remote hose? It goes into the main supply duct anyway that is after the furnace. It knows when it's OK to start up by using an air switch.
Smart move on Aprilaire. Give a wide wide berth to Honeywell. Damn did they put out crap steam units that I bought 8 of for a large house plus one for my own. What garbage.

 

[usernametaken]

I ended up with the Aprilaire 700m. Install was easy since the Max Caddy had a HUM out that triggers the humidifier whenever there is a call for heat and the blower is activated. I haven't had a chance to run it yet as my house is still setting at 50% humidity early in the heating season but I'm confident it will do what I want...

 

[usernametaken]

Since we are getting a little further into heating season, it was finally time to try out the humidifier. The house was dry enough that I got my first static shock so on it went. I was surprised and impressed at how quickly the Aprilaire brought the humidity level in the house back up. It is rated to work with either a hot or cold supply and having it plumbed to the hot side enables it to pull more humidity from the same amount of water allowing it to meet the humidity call more quickly. I think this is going to be the perfect solution during winter months. The only time I might end up a little dry is during the spring shoulder season as when my wood is exhausted and the temps are above 40, I switch to my LP furnace. This spring will tell the tale and if I need added humidity then, I may install another humidifier on the LP furnace side of the ductwork. If I do, I'll go with the automatic version of the 700 since the 700a has blower activation which is helpful on a traditional fuel furnace... but we'll cross that bridge if/when we come to it...

 

[JRHAWK9]

Has anyone here ever added a whole house humidifier to their wood furnace? Any perspective or experiences would be appreciated...

I have one installed, however I don't really use it at all anymore. I have a humidistat upstairs as well which has a temp probe ran outside to keep the house at the recommended humidity level for whatever the outside temp is. The humidifier is wired up so the only time it runs is when the wood furnace's blower circuit is energized and the humidistat is calling for humidity.

I don't use it much as it cools the supply air a noticeable amount, resulting in burning more wood. Plus now that my blower is speed controlled based on supply temp, it also messed with that. In real cold temps it didn't do much anyway for keeping humidity in the house, so we were still dry AND were not heating the house as well. We just live with the low humidity in the dead of winter. I tried a few years ago to get humidity levels up where they should be and was pumping like 20+ gallons of water into the house with TWO of those portable whole house humidifier consoles. It didn't take long for me to realize where all the warm/moist air was leaving the house. As the next warmer day, the house started raining from the very peak (we have 20'+ peak, seeing it's a log cabin style). The warm/moist air was leaving the heated space at the peak and freezing in place. Then the next warmer day it melted and it was literally raining all along the peak. I have not ran a humidifier since.

Here it is installed:


This is the outside view of the house peak only hours after it stopped snowing:


This is the unheated garage taken at the same time:

 

[usernametaken]

I remember seeing your pics when I was considering adding the 700M to my system. It does sound like your combo didn't work out well. It's funny how many variables effect whether the exact same product can work in one situation and not in another. So far so good here but as you pointed out, it isn't full blown, dried out winter conditions yet. I've started with it triggered off the HUM output on the appliance. However, if I find I'm not getting enough humidity mid winter, I can always use the supplied transformer that I have on the shelf to trigger it whenever the blower activates. Since mine comes on frequently even at idle once I reach the KIP in the plenum, that should about double the humidifier's runtime. I'm at the wait and see point right now though. I'm thinking it's going to work as is with my home being new construction and fairly tight... but only time will tell...

 

[JRHAWK9]

I'm sure yours is going to work out for you. We just lose too much heat/air out the peak , that's all. Using hot water will also work in your benefit, as I have mine tied into cold. Does yours have a fan which takes in the supply air from the plenum and blows it through some sort of media which has water running down through it? I guess some take in outside air and some take in air from inside the plenum.

Can you add a humidistat? That way you can adjust the humidity level and have it adjust accordingly from outside temps.

Remember, the heat of vaporization states it takes ~8,100BTU's to evaporate one gallon of water. In my case, when I was adding, say, 15 gallons of water a day....it was using up 121,500 BTU's a day, or almost 5,100BTU's per hour over the course of a day.

BTW, I re-thought what I was adding for water back then based on the size of the jugs and how often I used to refill them, and it wasn't 20+ gallons a day....it was about 12-15 gallons a day. Still a lot though.

 

[usernametaken]

Mine is the 700M and has a humidistat mounted in the return trunk that feeds the furnace. It's a manual one as opposed to the nicer digital one with outside air sensor that comes with the 700A. However, I'm down in the basement all winter filling the furnace so it's easy for me to make the adjustments manually. As to the air it's pulling, it's the type that has a fan that pulls air from the plenum, sends it through the media, and then back into the plenum. Here are a few pics of my setup...