Hygro refers to water, and thermal refers to heat. In buildings, you really can’t manage heat without also managing moisture. For example, if you increase how much insulation is in a wall, you may also be increasing the risk of moisture and mold problems.
There are four ways that buildings can get wet:
- bulk water leaks (rain dripping through a hole in your roof)
- wicking (groundwater being pulled up through a concrete foundation)
- air leaks (condensation inside a wall assembly)
- vapor diffusion (high interior relative humidity in the winter; high exterior relative humidity in the summer)
And there are just three ways they can dry when they get wet:
- drainage (intentional spaces between building components)
- air flow (convective drying, like your hair dryer)
- evaporation (low relative humidity and adding the sun for drying)
Frankly, four against three can add up to less than the greatest odds for drying.