humidifier steeling heat

[steeltowninwv]

i put a large humidifier in the same room as my insert and now its hell trying to heat my house....?????????????????

 

[pen]

The draft it produces w/ the moist air may make it uncomfortable feeling, but it can't "steal" heat.

pen

 

[woodgeek]

Water evaporation absorbs ~1000 BTU/lb. If you had a 'cool mist' or wick/drum/disk type humidifier running 3 gal/day, that is about 1000 BTU/h, or less than 5% of a typical insert output. If the humidified air is going up the flue it IS a waste of energy. OTOH, if you need the humidity in your house, you need to supply the heat somehow--no free lunch--a 'warm mist' or steamer humidifier will just add the energy to your elec bill rather than your wood 'bill'.

IF the effect is dramatic as you suggest--it is likely a cool air/fan blowing on you dealy. I would move the humidifier to a central space you do not usually spend time in--e.g a foyer or hallway.

 

[Battenkiller]

Water evaporation absorbs ~1000 BTU/lb. If you had a 'cool mist' or wick/drum/disk type humidifier running 3 gal/day, that is about 1000 BTU/h, or less than 5% of a typical insert output.

I've often wondered how much heat I lose by drying my wood indoors. If I use the black birch I just brought in as an example, I have 1/2 cord of wood that is 36% water by weight (a figure that I just determined using the oven-dry method) that I will get down to 20% MC in about a month. Figuring the SG of black birch at 0.71, that 1/2 cord oven-dried would weigh just about a ton. That means that the same 1/2 cord now contains about 1150 pounds of water. Losing 55% of that water to evaporation while getting it down to 20% MC means that I will be losing the heat from 630 pounds of water, or 630,000 BTUs, or 1,230,000 BTU/cord! That's 840 BTUs/hr lost during that month, almost 4% of my estimated average stove output.*

In the beginning, a lot of that water will condense again as it turns into liquid form as it is absorbed into the dry surroundings, but I'm just borrowing that heat for a while because the structure of my home will lose it all again as the RH drops inside after the wood has finished drying.

Is it worth it? You betcha. Number one, I need all the humidity I can get in this place, and as Woodgeek wisely points out, there is no free ride. Number two, I will gain more heat than I lost because of increased burn efficiency from the drier wood.

I have to be careful when and how I bring the wood in. Not only is it using heat as it dries, the whole mass of 3200 pounds of wood fiber and water is at outside temps. I brought this stuff in the other day after several nice days in a row raised the wood temp up a bit and lowered my heating requirements at the same time. Still, you can definitely feel the effect of this wood in the home even after it warms up. With the fan blowing against one face, the air coming through the other side is basically air conditioned air. To make matters worse, most of the evaporation occurs early on, so most of the heat loss occurs in a short time period. Usually in January and February, when drying is fastest, but when I need the heat the most. The net effect, however, is that the place gets real warm, humidity is raised just like I was using a humidifier... and its free.


FWIW I believe the moving air from the humidifier is creating a bigger sensation of heat loss than the actual amount lost, just like a breeze outside cools you off as it robs the heat from your body (just like the humidifier robs the water of its heat when it evaporates). I've always felt that is why folks with convective heaters and blowers seems to want higher house temps than us radiant types. Except for Backwoods Savage, who uses his radiant heater to keep his home in the 80s just to see the women take their clothes off. %-P


*It's morning and I haven't gotten the cobwebs out yet and I may have made a mistake somewhere, but I know no one will check out my calculations anyway, so I'm golden.