In the winter, my house (~2500 sqft) becomes unbearably dry. Last winter, my wife and I used a tiny humidifier for the master bedroom to keep us from completely drying out, but since then I have been exploring a whole-house solution, complete with humidistat. It seems well within my ability to install it.
The trouble is, everywhere I've read that a whole house humidifier should not be needed. Normal humidity, they say, should be maintained simply by normal activity (showering, cooking, etc.). If the house is dry, it's far more likely to be that I have leaks (say, around my recessed lighting), and then adding a humidifier would risk mold issues.
So this is my dilemma: in order to find air leaks, everything I've read is that I'd need to have an HVAC guy come out with a blower door, which is very not DIY. So, expensive. Or, I could go boldly forth and just install the humidifier, in spite of the fact that I might not need it.
So, what should I do? Any guidance would be most helpful here.
Best Answer
I went though a similar debate last year and ended up getting a whole house humidifier. I never remember reading that you should be able to get the humidity level to normal levels though normal means (shower, cooking, etc). In a big house, that is most likely not possible. Do you have a humidistat now, or does your stand alone unit give you a reading? I would recommend you getting one of those first to see how bad it truly is. If I remember correctly, if your humidity is below 30%, you could actually be causing harm to yourself and your home.
Our house approached 25%, which is dangerously low. Some of the driest deserts in the world don't get that low. For example, Las Vegas ranges from 21%-39%. You may be living in conditions that are way too dry.
All that being said, I knew we needed to do something. You mentioned worrying about mold, sure this could happen if you raise your humidity very high, but think about it, in the summer your home probably approaches 80%-90%. With humidity that hight, and the warm temperatures, that natural condition is more likely to produce mold than your 70 degree house in the winter. Plus, you will find just increasing your humidity to like 35%-40% with your whole house humidifier makes it very comfortable. AT that level, mold is unlikely an issue. The added bonus us that the more humid the house is, the warmer it feels. Again, just like in the summer, a humid 90 degrees is much warmer than a dry 90 degrees. We found we were able to decrease the temp of the house simply by adding a little humidity. Used to be 72 degrees at about 25-30% humidity, we now keep it at 70 and 35-40%. So we save heating costs there.
Ok, so what kind to buy? I researched the various types of whole house humidifiers, and it comes down to three types.
I opted for the steam model, mainly because of the low maintenance and ability to control the desired humidity more easily. I installed it in an afternoon, it was easy to do. Most of them come with high end humidistat / thermostat, that would replace your existing house thermostat. Then the system knows how to control the furnace to optimize the output. I went with the Honeywell TrueSTEAM series and it has worked great. Good Luck!
Here are a few other descriptions:
http://www.just-humidifiers.com/works.php
http://www.guide4home.com/care-hf/whole-house.htm