Wood stove + whole house humidifier

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kolyur

Member
Nov 30, 2009
24
Northeast Ohio
I've decided I need to add humidification to my HVAC system. The house gets very dry during the winter months, in part due to wood burning I suppose. My primary heat is a high efficiency Amana gas furnace and I use a PE Super insert for supplemental heat. I might have the stove going for days or weeks at a time depending on the weather.

After doing some research I see there are several options for whole house humidification:
1. Evaporative (bypass style)
2. Evaporative (powered fan)
3. Steam

The evaporative units seem to be the most common and are certainly the cheapest. They mount right to the ductwork and require heat to evaporate the water--normally this comes from the heated air in the supply side of the furnace. The problem I anticipate is that my furnace does not run when I'm burning. I can force the blower to run but since there's no heat in the airstream, I won't get any evaporation. I have read that you can plumb hot water to the humidifier to make up for this (which I could easily do--hot water heater is right next to furnace). But I've heard mixed reports about how effective this is.

The steam units are newer technology and seem to be the better choice for my situation. Since they boil water to generate steam, moving air is all that's required in the plenum. The drawbacks are mainly cost-related: higher install cost, more maintenance, more $$$ to operate. Everything I've read indicates that a $40-60/month spike in your electric bill is typical. Plus I'd have to run a new circuit over to the furnace since they pull 10+ amps.

Any opinions from those who have installed either of these units in my situation (supplemental wood burning)? I'd really like to know if I could get by with an evaporative unit, since the up-front and ongoing costs are so much cheaper. I'm thinking it would be OK since (1) my insert won't burn all night, so there are always times when the furnace kicks on and the humidifier would work, and (2) I would plumb hot water to it so I might get at least marginal efficiency the rest of the time. The specific units I'm looking at are Aprilaire 600/700 (evaporative) and Honeywell Truesteam (steam).
 

Jackfre

Member
Oct 3, 2011
106
N CA
The units that require hot water need to be quite close to thewater heater. Otherwise, the heat loss from transmission, even if insulated, kinda reduce the efficiency. I think you are better with a stand alone console unit to co-ordinate operation with a wood stove. Your run cycles are to intermittent with the furnace to give the humidification you seek and you could end up with a wet pad sitting in the dark in the plenum that may get a tad moldy. I like UV lights with a humidifier so they can kill any bacteria growth that might pop up due to the humidifier. Not worth the chance or expense in my book, but then I tore all the duct out of my house :)
 

realstihl

Minister of Fire
Dec 4, 2007
525
eastern kansas
I have an evaporative setup. Aprilaire 600 on a 3.5 ton heatpump. Hopefully your water heater is close as I'd suggest hot water. I do have the same problem but it takes care of itself during daytime hours when noone is there.
 
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