One of the best energy-efficient features a home can have is insulated windows. They help keep the temperature indoors comfortable, but it’s not uncommon to see these windows sweating during temperature extremes. If condensation forms on the outside of a window, that’s good. It means the window is doing its job. But condensation inside is a problem. It usually means outside air is somehow migrating inside or humidity levels inside are too high. To help combat this moisture, seal any gaps and cracks surrounding the insulated window unit using a good quality acrylic latex caulk. Be sure to use ventilation fans in bathrooms and kitchens any time you bathe or cook to remove excess moisture from those rooms and, if needed, use a de-humidifier to lower indoor humidity. The ideal range you want inside is between 35%-50%.