Maybe you or someone you know has a basement rather than a crawl space. Basements can also be affected by moisture and humidity. If moisture enters your basement through leaking pipes or a crack in the basement walls, this can certainly cause humidity to rise in your home. Just like with a crawl space, the warm air will rise into the other areas of your house. Your HVAC will do its best to maintain temperature and will have to work harder as the warm air travels.