Where a pane of glass separates a warm, humid indoor environment from a cool outdoor environment, condensation forms on the window. The moisture can contribute to mold growth and even damage wall materials as water seeps into them. Puget Sound Energy provides utilities to the famously drizzly northwest corner of Washington state and offers these defenses against condensation:
- Take steps to lower indoor humidity to below 60 percent, like fixing chronic leaks and increasing air movement by fans and central heating.
- Use double-pane windows or apply storm windows over the top of single panes to increase insulation between the indoor and outdoor atmospheres.
- Replace aluminum frames — which quickly conduct household heat to the outdoors and provide a cold surface to collect moisture from indoor air — with vinyl frames (or insulated aluminum ones), or cover the aluminum arrangements with storm windows, like you would a single-pane window.
If you install storm windows, make sure both the storm window and the original inner window are well-sealed to prevent moist air leaking into the space from the indoors or cool air from leaking into the space from outside. Condensation can result from either problem.
Reference: Puget Sound Energy is Washington state’s largest and oldest energy utility, serving nearly 1 million electric customers and more than 650,000 natural gas customers, primarily in the Puget Sound region.