Rolf, 48%

[Tim Coates]

Rolf & Ruth,

Although South Dakota is not as far north as most people want to put it in
their minds, we do have to watch moisture in the winter.  Condensation on
the windows has always been the rule of thumb around here.  That means one
can have higher levels of humidity during warmer time periods.  Being a
weather watcher is a must.  Getting caught with the furnace humidifier set
for 40-45% and the temps dip to 40 below (can happen here in half a day)
will cause damage to the house structure (seen it happen).  Fortunately,
the weather service has been getting quite good with storm predictions.
Each house is different as to how it handles humidity, though.  The window
technique has been the best rule for my customers the last 25 years.

I also always make sure my customers know how to adjust and maintain their
furnace humidifiers.  If they don't have one I highly recommend they get
one.  Now if I could only get my university physical plant people to care
as much as my in home customers.

Tim Coates
University of South Dakota
University of Sioux Falls

Rolf von Walthausen & Nancy Larson wrote:As a guideline I have found window
condensation to be a good indicator:

> if you start to see your windows fog up or moisture condense around
> window panes then the indoor levels are probably too high for your house
> in its present condition.