If you’ve experienced at least one year living in the Triangle, you know that high humidity makes heat much harder to cope with. You can expect to run your home’s air conditioning system longer and harder to overcome the additional heat.
Well … the feeling of additional heat. High humidity doesn’t raise the temperature of the air: an 85°F day is still an 85°F day no matter if the relative humidity is 15% or 90%. What happens when humidity levels are too high (over 60%) is that more heat becomes trapped inside your body. The increased moisture in the air slows down your ability to release heat through perspiration, so you end up feeling hotter than if you were able to shed most of that internal heat.
Basic science lesson over. What does this have to do with your air conditioner? Plenty. If you feel your air conditioner isn’t doing much to combat the high humidity in your house each summer, that’s because it wasn’t designed to.
Humidity and heat during the summer can combine to make what might otherwise be a pleasantly warm North Carolina day into it a tough slog for almost anybody. The reason for this is that the increased moisture in the air is something like putting on an extra layer of clothing: it traps more heat inside the body, making temperatures feel warmer. So an 80°F day will feel like it’s actually 90°F. When relative humidity rises above 60%—a common event around here—the discomfort kicks in. 
