What drives the decision
Film fits best when existing glazing is serviceable and the goal is optical, solar or surface-related.
What changes the budget
Window replacement costs much more but can solve failed seals, deteriorated frames and other problems film cannot.
Operations and lifecycle
Compare expected service life with any planned façade replacement.
Planning boundary
Serious air, water or structural façade problems need building-envelope professionals.
Educational planning only. Actual construction, code compliance, regulated systems, hazardous materials and safety-critical work require qualified professionals and current local requirements.