60% humidity sounds wrong, what kind of humidistat do you have . Was it
calibrated, Taylor sells them up to 25% out of calibration, Menards, Ace
all had the same junk. I had to find a large display analog and
calibrate it. 60% rh at 10f or less and your exterior walls would be
literaly wet and your windows would have puddles under them. A little
condensation as you describe happens, but depending on window type may
not be a concern.
Do you have dual pane argon, what brand . What temp do you keep the
house in, farenheit. Dehumidifiers can frost some as high as 67f and
not work. What are winter temp ranges in, farenheit.
First you need a good humidistat.