Humidity Is No Sweat

(or at least solving it is doable!)
 

by George Porter

Winter  is almost here  once  again  and  we  are  confronted with  the  problem of  having colder  outside weather meeting the warm heated air inside a manufactured home, resulting in condensation.  

Site preparation is a factor in humidity in factory built homes, however, not the only thing that can affect condensation. Even if it is the only thing  we  can  do  about  it  as  installers.  Perhaps  part  of  our  job  as  installers  is  to  educate  the consumer that all his problems may not lie with someone else. With that in mind, and because it’s winter, I thought it would be good to talk about the problem.

First,  a little background. Water comes in three stages. There’s liquid like  the  water  you  drink, there’s ice like you  put  in the water  you  drink and water can also occur as a gas. It’s  invisible, you can’t  smell it,  but  you  can feel it.  It’s  known as humidity. 

As our friends in the South can tell you, warm air holds a lot more humidity than cold air. The  driest  place on the face of the earth is the South Pole and the wettest places on the  face of the earth are jungles and such along the Equator.

Consequently, if you would take some of the air out of the jungle and put it at the South Pole, the water would have to go, because it could not hold it as the temperature changed.

As the  humidity leaves the air in the form of a gas, it turns into liquid, and if it’s cold enough, that  liquid  will  then  turn  to ice.  That’s  what  happened  to  all  the  water  at  the  South  Pole.

Whenever they do happen to get some in the air it winds up on the ground in the form of snow.

It  doesn’t take these  kinds of extremes to  produce  a  similar  reaction  in  HUD Code manufactured  housing.

Humidity and condensation are natural occurrences and have nothing to  do with the  structure  of the  house,  manufactured or  otherwise.  Air  can  only  hold  a  limited  amount  of  water  vapor depending on its temperature. When air is holding half as much water as it could possibly  hold at a certain temperature, it is said to have 50% humidity. When air is holding 100% of all the water it could  possibly  hold  at  a  certain  temperature,  it  is  said  to  be  at  100%  humidity.  When the moisture in the air tries to  exceed 100% humidity, it changes back into a  liquid  and  appears  as steam or condensation.

There are two  ways  to  change this  relative humidity. Starting with it’s ability to  hold water is relative  to  its temperature hence the term relative humidity. You can increase the  relative humidity  by  simply increasing the water in the air or by lowering the temperature. When you exhale on a cold day, the warm moist air in your  lungs leaves your  mouth and  forms  a little  cloud.  Because  the  cold  air your  breath  is  entering  will  not  hold  so  much  water,  the  excess  moisture  is transformed  into vapor in front of your face. This same moisture can form on any  cold surface. If you  have a cold glass of water in a warm house, it will begin to sweat and drip as a result of moist air touching the colder layer of air very close to the glass.

All of these will happen inside any home. The sweating and water  running down the windows is actually a safety gauge. It’s telling you that there is an excessive amount of moisture in the  home and that you must lower the humidity. The same thing that’s happening on your windows can be happening inside your walls and roof and every other part of your  house. It  can cause warp,  rot, mildew, paint failure in general, in short, do significant damage to the home.

There  was  a  time  when  our  industry  was  not  bothered  by  this  problem.  Some  of  the  early examples of our industry always seemed to have a little breeze blowing through them, summer or winter.  When  you  had  large  amounts  of  outside air  infiltrating  throughout  the  home,  it  was virtually  impossible  to  trap  any  moisture  laden  air  within  the  home. Since those  early  years, however, our industry  has  done  a  fantastic  job  in  thoroughly  weatherproofing  and  sealing our housing.  Our  homes  are  extremely  tight  as  evidenced  by  the  mandatory  air  exchange  systems found in many homes today. We were the first type of housing that was required to have outside air going into the fireplace so that it wouldn’t suffocate the people in the house by  burning up  all the oxygen.
 

All  of  this  produces  very  low  heat  bills,  but  it  also  allows  us  to  develop  our  own  mini environment  inside  the house  and  it  is  that  environment  that  must  be  controlled.  Only  the homeowner can do it because it is his lifestyle and habits that will determine the  humidity within the  home. Listed below are some activities and the amount of water they  put
in the air in your home if you do not use an exhaust fan or vent the home in any way:

Other sources of water could be house plants,  aquariums and anything else that  allows water to evaporate. If we keep adding water  from these  sources on a daily basis and never remove it, the home will be destroyed. In fact, the average family of four can easily add a 150 lbs. or more than 18 gallons of water per week to the air in the home. All of this moisture must eventually escape.

The  safety  gauge would be how much water  you  see condensate on  your  windows.  A  better gauge would be a humidity gauge easily purchased at most  hardware or department  stores.  DO NOT USE a portable kerosene heater to warm the home. The expense of the  problems caused by the  excessive  humidity  (4-1/2  pints  per  gallon)  far  exceed  whatever  savings, if any,  can  be obtained over running the heater that came with the home. 

Put lids on pans  when water is boiling in them. Use the exhaust fan in the kitchen when cooking. Always  use the exhaust fan when you are taking a shower, or open the bathroom window. Open a few windows in the  house every  day for a minute or two, even if the air outside is very cold. If you  air out  your  home in this manner, it will not only bring fresh air in the home, but it will also quickly lower the  humidity inside the house. If all else fails, the customer will have to  purchase and use a dehumidifier. If the installer has placed the  6 mm of polyethylene  on the  ground beneath the  home as  recommended  by the manufacturer of the  home and has properly  vented the  skirting, he  has  done  everything  he  can possibly do to  help alleviate this  problem. The  rest  has to  be left up  to the customer. The  best thing we can do as installers is be absolutely sure that  the customer is aware of this and hopefully before he gets the problem. 

Many companies and manufacturers of windows  publish  pamphlets on condensation. If you  live in an area prone to the problem,  please  be  sure  that  one  of  these brochures is lying in the house or presented to the customer at settlement. If he says he never had this problem in any other house he ever had, tell him that he may never have had a house built as tightly and  installed  as  precisely  as  the  one  he  now  owns.  And  the  fact  that  we  have  these problems is the proof. # #