Air humidifiers, what's the point?

[mistermack]

I think the way you do it makes a difference. I do what I described, I just put a pan of water on a gas ring at it's lowest setting.

In a way, some of the humidity is free, it's a bye-product of burning the methane.  None of the heat or water vapour generated is escaping up a chimney, or out through the boiler vent. And, if your windows do steam up, you're getting some energy back as heat. 

I'm sure the money involved is probably minimal. It doesn't cost much to run a gas ring on minimum. But I do prefer the feel of slightly raised humidity in winter. 

[J.C.MacSwell]

5 hours ago, swansont said:

 

9 hours ago, swansont said:

Do you have numbers to back this up?

Water's enthalpy of vaporization is 40.65 kJ/mol. 

With regard to temperature related comfort that would effect the  balance of the equation on both sides. How much less vapourization may or may not happen on your skin or clothing and how much you might lose in the air from air exchange with outdoors or from condensation on the walls (though I assume you should keep the dew point below the temperature of your perimeter)

Obviously it would depend on a number of factors. I am assuming there would be an optimum at neither extreme of the humidity scale but I do not know that. Possibly dryer but warmer might be the most economical in that regard?

[swansont]

15 hours ago, mistermack said:

I think the way you do it makes a difference. I do what I described, I just put a pan of water on a gas ring at it's lowest setting.

Water doesn't care how it's heated. The efficiency of the heating will only tell you how much to add to the energy cost.

[mistermack]

On 19/01/2018 at 10:54 AM, swansont said:

Water doesn't care how it's heated. The efficiency of the heating will only tell you how much to add to the energy cost.

Well, assuming that it's winter, and you have to put some heat on, then a lit gas ring is more efficient. If you light a gas fire, or gas boiler, a lot of the heat and water vapour from the flame goes out through the chimney, or the vent in the wall. And you also suck in cold dryer air to replace the warm more humid air that's leaving, in many systems. My boiler is pretty new, and has a fan powered feed of outside air to the boiler to avoid that.

So lighting a gas ring, even without the pan of water, is more efficient. So long as your house has a normal level of ventilation and you don't overdo it, it's safe, and it's going to cost less than lighting the boiler for the same benefit. 

Whether putting the pan of water on it is actually cost efficient would need a study to see what temperature people would choose as the optimum, at different levels of humidity. The simmering water would use some heat, but raise humidity. I'm simply guessing from my own experience that you would save. 

The other benefit in my case is that there is always an instant supply of nearly boiling water available in winter. If I set my gas boiler to the "comfort" setting, it keeps some water constantly hot, so that it can supply nearly instant hot water. That's actually quite a costly feature, as the boiler will keep cutting in and out to maintain the temperature of the reservoir 24/7. I have an instant supply nearly boiling, for washing up or cooking, which doesn't cost any extra. ( I've never liked dishwashers )