If you raise the attic temperature the rh in both places would be the same.
Remove humidity from attic.
As the moisture migrates upwards to the colder attic areas during the winter months the relative humidity is increased to the point that condensation can occur on cold surfaces.
So the first step is to seal the air leaks.
Use a wet vacuum to remove any excess water from this space before you start the mold removal process.
Here is a link to an article that describes the work.
By adding moisture to the lower floor you increase the partial pressure of the water vapor which pushes it to areas of lower vapor pressure like the attic.
However you ll need to drain it frequently in order for it to function properly.
Look for energy star qualified models which consume less energy than conventional dehumidifiers.
During winter months humidity from this escaping air can condense on cold attic surfaces leading to mold.
Placing a dehumidifier inside the attic will help to draw out moisture from the surrounding environment.
This can result in mold rust and deterioration of wood and structural fasteners.
A dehumidifier can remove it.
Put a dehumidifier up there plug it in set it between 50 and 60 rh and forget about it.
So they equalize pretty quickly.
All of these areas when added up can lead to a large amount of heat loss that will creep past your insulation and get into your attic often carrying higher humidity levels along with it.
If your humidity level consistently rises above 70 percent consider installing a.
Once the dehumidifier s storage tank is full it won t be able to remove any more moisture.
In warmer weather an air conditioner cools indoor temperatures and helps remove humidity from your home.
They re effective in laundry rooms basements bathrooms and any room that isn t air conditioned or has poor air circulation.
Caulk and expanding foam are two common products used for air sealing.
High humidity in an attic is usually caused by air leaks in the ceiling of the top floor of your house.
If high humidity is a problem you can t overcome by other methods remove moisture from the air with a dehumidifier.
The difference in the two spaces is the dry bulb temperature.