Offered as a low-cost and quick alternative to window replacement, early interior storm windows were unattractive, prone to damage and had short service lives. Today, manufacturers offer interior storm windows that have better aesthetics, good performance and an improved service life.
Windows can be mounted permanently or they can be mounted in a way that allows removal for natural ventilation. Glazings are available in both acrylic and tempered glass for applications where impact resistance is a factor. Glazings are also available with low-E coatings to further improve energy efficiency.
If facility executives need to replace windows but lack sufficient funds for the project, interior storm windows can defer the project until funding is available. The interior storm windows will improve the energy efficiency of the windows at a much lower cost. However, if the existing windows and frames are deteriorated to the point where they are allowing water to enter, interior storm windows may not provide adequate protection.
Interior storm windows also can solve problems with particular applications that affect a limited area of a facility. Since they are installed inside and do not change the exterior appearance of the facility, they can be applied to individual windows as needed. 
James Piper, PhD, PE, is a writer and consultant who has more than 30 years of experience in facilities management. He is a contributing editor for Building Operating Management.
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