Short Answer
Sometimes. Replacing both can make it easier to properly integrate flashing, weather-resistive barriers, trim, siding, and sealants. But they do not necessarily have to be replaced simultaneously.
Detailed Explanation
When siding is being replaced, the contractor has full access to the wall assembly, including the area around windows. This makes it an ideal time to also replace windows if they need it, because the flashing and weather-resistive barrier can be properly integrated with the new windows. If windows are in good condition, they don't need to be replaced — but the flashing around them should be evaluated and corrected if needed during the siding project. If windows are nearing end of life, replacing them during the siding project can save money compared to doing them separately later, because the scaffolding, tear-off, and wall access are already in place. The decision depends on the condition of the windows and the homeowner's budget.
Why It Matters
Coordinating window and siding replacement can improve installation quality and save money, but forcing window replacement when it's not needed wastes budget.
Questions to Ask Your Contractor
- ?Are my windows in good enough condition to keep during siding replacement?
- ?Should the flashing around my existing windows be replaced during the siding project?
- ?What's the cost savings of doing windows and siding together vs. separately?