Friday, December 12, 2014


it seems that complaints about high humidity are usually about warm places. steamy tropical jungles. new jersey in summer. hawaii. here in humboldt county the air is quite damp. at 12:30 pm december 11 the relative humidity was 82%, and it wasn’t raining. we live in a house that was built at least 55 years ago. no insulation. even the newer double pane windows get condensation.

there is a gas-fired wall heater that keeps the house warm enough. except for the room where we sleep, an addition down a long hall from the heater. we fixed that fairly well with a fan on the floor sucking low, cold air from our room, causing the higher warm air close to the furnace flow back into our room. so we went along for a month into colder, wetter weather keeping warm using the fan to evaporate any visible condensation, thinking we were keeping ahead of the damp.

well, there was the discovery that my only leather shoes, in a closet next to an exterior wall, had some green mold. hmmmmm. i moved them out of the closet and now we leave the door open.

but the damp is like rust: it never sleeps. it just creeps on in.

we keep a printer, a file cabinet, and a modem/router in a spare bedroom. we call it the office. there is a stapler, tape, printer paper, envelopes, and a stack of unfiled papers. robin went to get an envelope and found that all of them in the box were sealed shut. and the printer paper felt damp.

we wanted to know how humid is it in our house. we resorted to science. i recalled the drybulb/wetbulb method of determining relative humidity. we only have one thermometer so i recorded the dry temp (22 C) and then wrapped the thermometer in a wet sock and set it in front of a fan. after a decent interval i recorded the wet temp(18 C). a check with a handy weather calculator in the intertubes gave us a relative humidity of 68%. a bit of research indicated that a healthy level of humidity in a house would be below 50%, maybe best at 35%. we are all wet.

                  dry bulb                                        wet bulb
we decided that we needed a dehumidifier. we ordered one. it arrived. will report.


  1. When we have rented beach houses in Oregon, they often have dehumidifying devices. I think it goes with the territory but not sure how far south before it ceases being an issue.

  2. Yep. A humidifier will made a big difference!

    During the part of the year when I can have my windows open, the indoor humidity very occasionally drops to 50% here in Bellingham. It also drops, of course, when we have freezing weather. For the most part, though, my belongings stay dry with an indoor humidity of 60-65%. The towels in the bathroom dry out by themselves at that humidity.

    My home is a second floor condominium. The people who live in the ground floor condominiums here at this complex all have humidifiers to keep the damp at bay. A great invention! They not only dry out the rooms but keep them warm as well.

  3. Pretty clever to do the wet-bulb test.

    We have high humidity in the summer, but not in the winter, aside from the humidity we generate in the house with showers and whatnot. Even when we get humidity from the Gulf or the Atlantic in the winter, the indoor relative humidity is usually pretty low once the air is heated up. That doesn't stop our self-generated humidity from condensing on the windows in cold weather.

  4. rain... the damp is definitely an issue this far south.

    am.... we did open all the doors and windows when the outside humidity was lower than inside.

    mark p... i have all sorts of odd stuff in my memory. sometimes something is actually useful.

  5. Well aren't you clever. I would have never thought of that. I was glad to see your last sentence. It really will make a difference.

  6. ac... that was the fourth time i emptied that much water. each time was about 15 pints.

  7. we definitely had humidity problems when we lived in japan -- shoes would rot in the closet. not as bad in the main part of the house, because we mostly used a kerosene space heater, which did dry things out.

    there were these dehumidifying things you could put in the closet -- some kind of crystals in a lidded bowl with vents on the top -- and they would fill up with water.

    but i just found this amusing post about eco ways to deal with moisture:

  8. japan in winter -- there were torrential rains, and steady rains, and we had no insulation to speak of. this was in 1988-9. no central heating; no a/c for the also humid summer.

    when we set up a small safe electric heater in the kids' room, our landlady worried that there was an electric leak because it took so much more power than usual. (obviously, also before computers and all kinds of other electric devices, such as those newfangled dehumidifiers.)

  9. Roger -you crack me up you are such a smart all-around jack of all trades. I had never even thought about how to measure humidity in house. I just figured that was something I had no control over except via A/C or the furnace!