When air leaks around windows, energy is wasted. Energy is also transferred through the centers, edges, and frames of windows. Eliminating or reducing these paths of heat flow can greatly improve the energy efficiency of windows and, ultimately, of homes. Before applying new caulk, old caulk or paint residue remaining round a window should be removed using a putty knife, stiff brush, or special solvent. After old caulk is removed, new caulk can then be applied to all joints in the window frame and the joint between the frame and the joint between the frame and the wall.
Low humidity is important during application to prevent cracks from swelling with moisture.
Warm temperatures are also necessary so the caulk will set properly and adhere to the surface. Weather stripping is a narrow piece of metal, vinyl, rubber, felt, or foam that seals the contact area between the fixed and movable sections of a window joint. It should be applied between the sash and the frame, but should not interfere with the operation of the window. The statements contained herein are based on information known to EREC and NREL at the time of printing. Hopper Awning Frame types can affect the energy efficiency of a window.