AH, Michigan in November! The cheerful grey skies, the sparlking grey slush on slick grey pavement, the bare grey trees dancing in the arctic breeze! No wonder rational people become phootball phreaks! They need the cortical stimulation of watching maize and blue and green and white battling it out on a nearly green field. Go State!
November is a good time to talk about humidifiers. I'm just about to turn mine on. I realize most people turned off the water valve when the furnace started a few weeks ago, but that is one of the main problems with central humidifiers; people run them when they don't need them. Therein lies the raison d'etre of this article.
The ideal relative humidity in a home is 50%. As the furnace runs, the house air gets appreciably dryer than this, and then bad things happen.You pick up static electricity from the carpet and deliver it to your computer; (gzz-zapp, right into the Windows registry!), your nasal mucosa dry out, leaving you vulnerable to cold viruses, and your hair starts looking like you borrowed it from Beethoven. If the air stays dry long enough, your wood furniture will start to shrink and crack, and your floor will develop even more squeaks. OK, that part is pretty much common knowledge. We have humidifiers to prevent these problems. But what happens if you get over 50%?
The air around us, and all the surfaces in our homes, are inhabited by various micro-organisms. Fungi, such as molds, plus the usual assortment of protozoans, bacteria and viruses. Molds are very common, and in low amounts are harmless to most people. But, the higher the humidity, the faster these mini-bugs reproduce, and various respiratory problems can result. A lot of what we think of as winter colds can be traced to these beasties.
Further, the excess moisture starts looking for somewhere to go. It permeates the entire house, and will condense on the first cold surface it comes to. This is often the inside surface of the roof. Open your attic hatch and look up. Do you see frost, or a droplet of water on each of those nail points? That's excess humidity. If you see black mold on the inside surface of the roof boards, you have a serious moisture problem, and a possible health hazard. If you see condensation on your window frames, you have too much humidity. (Exception: if your windows have metal frames, and the outdoor temp is lower than 25 degrees, condensation is almost unavoidable. The black gick on the window track is mold, and it can be harmful to your health!)
So the secret is to keep the humidity at 50%. Is that actually possible? In the real world, no. Remember, your house air is replaced by outdoor air from 2 to 12 times each day, depending on how tight the house is. Outdoor humidity levels vary rapidly. Indoors, the amount of water vapor your family generates by normal activites, such as bathing, laundry and cleaning also varies. Therefore, the amount of water your humidifier needs to add varies widely hour to hour, day to day. The humidistats on the equipment are very crude, and often do nothing at all. If setting your humidistat to a certain level will prevent signs of too much or too little humidity over a period of a week or more, you are lucky. For most of us, that won't work.
So, what's the answer? In my opinion, we will eventually be bailed out of this trouble by technology, maybe some really accurate little humidity detectors in each room, reporting by radio signals to a computerized climate-control system, or some such. In the mean time, the best we can hope to do is stay between the extremes. If you see signs of excess humidity, you may need to simply TURN THE DARN THING OFF!. Really off, not just at the humidistat, but at the water valve, too. Find the humidifier on the ductwork near the furnace, and trace the small copper or plastic water pipe from the humidifier back to the point where it connects to the main water supply. There should be a valve there, usually with a T-shaped handle. Twist it all the way in (clockwise) to shut it off. When you start to notice dryness, (static shocks, for example) turn it back on for a few days, then turn it off again! When things get really nasty outside, and the furnace is running several hours every day, leaving the humidifier on all the time is probably OK. That will get you from Christmas to about St. Patrick's day. Then, try turning it off again. The final turn-off will probably be around Income Tax day. (How apropos!)
If your humidifier is a drum type, don't forget cleaning out the pan and rinsing the foam sleeve. City water contains a certain load of minerals, and well water often has a lot more. As the water evaporates into your house, the minerals are left behind. A year's worth of minerals will turn that soft foam sleeve into a rock! Those tablets that some people drop into the pan simply keep the minerals from crystalizing, but they are still there. Bi-monthly cleaning is a good idea, around the same time you change the furnace filter. You do change that filter every 2 months, don't you? I thougth so! ; ) I have a basic instruction sheet on cleaning drum-style humidifiers, E-mail me if you'd like a copy.
If you don't have a furnace-mounted humidifier, you probably haven't read this far, but just in case, I have a bit of advice. Don't get one. Think 'portable humidifier'! The central type I have been talking about suffer a lot from the "out of sight, out of mind" syndrome. A portable is right there in the room with you. You clean it when its dirty, and you shut it off when it's not needed.
Questions? Comments? Friends who could use this information? Suggestions for future articles? Drop me a note at matt@inspectmichigan.com . Also, please check out the web site.
Farewell,
Matt (Sherlock) Bezanson
P.S. If you don't think naturally-occuring fungus can be harmful, try entering "stachybotrys" in any search engine, and see what comes up!