Replacing Old Windows – Replacement vs. Retrofitting

Once you have made the decision to replace your old windows, you need to determine if you will need a full window replacement, a retrofitting (inserting windows into the existing frames) or sash replacement. Based on your home’s window and wall conditions, you can determine the best option by consulting with your replacement contractor or energy auditor. This Weather Shield video presents an overview of each of these options for window replacement:

Full Window Replacement: This process involves removal of the existing frame with the new window placed into the position occupied by the old window. This is a great time to fix air or water leakage problems that may have occurred around the old frame.

Retrofitting: The original frame is left in place but the side jambs, trim and old sash are removed. The opening is filled by the new window. It’s possible to accommodate slightly out-of-square conditions of the existing frame, but if these problems are significant, full window replacement is the better option.

Sash Replacement: Replacement sash kits which include jamb liners are offered by many manufacturers. This is a relatively easy installation, but to ensure air and water tightness, the existing frame must be in good shape.

No matter which window replacement option you choose, you will be able to find energy-efficient products for your project. Be aware that while sash kits may have NFRC energy ratings, the Energy Star Program only applies to whole windows and not to retrofit sash kits.

Windows perform well only if they are properly installed. Follow the manufacturers’ recommendations regarding installation (whether DIY is an option or trained professionals are required). Manufacturers may also recommend installation certification programs or in-house or third-party installers. To ensure an airtight fit and continuous water barrier to prevent condensation, drafts and water damage, quality installation is critical.