Window replacement costs in Honolulu

For windows, the number Honolulu's energy code cares about is solar heat gain, the fraction of solar warmth a window lets indoors.

Under the city's amended code, a replacement that includes new sash and glass has to meet the same solar heat gain limit as a new house, and you can average it across all the windows you replace. Swapping only the glass in an existing window carries no requirement. On the code's Tropical Zone path, open to homes that are no more than half air-conditioned, unheated and below 2,400 feet, the limit is 0.25 for a window without much overhang above it. A window under a deep enough overhang can go to 0.40, and past a projection factor of 0.50 there's no limit at all. Jalousie windows are exempt on that path. So the eave above your window is part of the math.

Permits are lighter than you might expect. The Department of Planning and Permitting lists replacement of windows or doors among common jobs that may not need a building permit, though the work still has to follow city law.

The housing leans on one era. About one home in four in the Honolulu metro was built in the 1970s, the biggest decade in the Census count.