Many older Hawaii homes save energy through passive design, according to Kiersten Faulkner, executive director of Historic Hawai‘i Foundation, whose mission is to preserve Hawaii’s historic buildings and sites. For instance, older homes are often oriented to let in maximum daylight while minimizing heat from the sun, and windows are placed to let in cooling tradewinds and promote cross-ventilation.

But when Pat and Ed Chung bought their 1921 Craftsman-style bungalow in Manoa in 1983, all the windows were nailed shut.

“They’re the original double-hung windows with that wavy glass, but they were nailed because you couldn’t lift them up or down since all the ropes were broken,” Pat Chung said.

“All the frames had to come off to fix the casings, lead weights and ropes inside.”

But it was worth it: The old windows are still in place and functioning smoothly.

Preserving such beautiful features of an old home is also environmentally sound, Faulkner said, and windows are one topic in a workshop series, “Greening Measures for Hawaii’s Heritage Homes,” presented by Historic Hawai‘i Foundation in partnership with the Honolulu Chapter of the American Institute of Architects. It starts Monday evening with an overview in which the Chungs will speak and show pictures of their whole-property “green” rehab.

“For 35 years we’ve been restoring but keeping all the major features original,” Pat Chung said.

The 1,600-square-foot, single-level house was one of several kit homes designed by architect Ray Morris for Lewers & Cooke, Chung said. The floors throughout were in good condition and only had to be refinished. Where carpenters put in drywall, they put the same molding back or matched it perfectly, and over the years, Ed Chung has done little remodeling jobs, utilizing as much of the original wood as possible, his wife said.

Because the wavy window glass was historic and beautiful, the Chungs didn’t replace it with Energy Star double-glazed panes or cover it with energy-efficient films, striking a balance by opting in favor of history there while saving energy elsewhere with new EPA-certified, Energy Star appliances and other investments.

Rainwater catchment not only irrigates the Chungs’ extensive produce gardens, fruit trees and fishpond/hydroponic system, but the rain gutters prevent water from dripping down the sides of the house, eating through the paint, rotting wood, causing mold and undermining the foundation.

The five seminars, to be held at AIA Honolulu’s Center for Architecture on Fort Street Mall, are designed for anyone who owns, rents or manages an existing home, and not exclusively a historic one, Faulkner said.

“If you’ve got a home, you’ll learn some very practical things that will reduce your use of natural resources and save you money.”

But if you do have a historic home, or are interested in owning one, the series covers national standards for preservation that address a home’s unique architectural integrity.

For instance, given the distinctive shapes of Craftsman or mid-century modern rooflines, you might want to consider how the placement of a photovoltaic array will affect the look of your roof, or even whether you want one at all, Faulkner said.

The Chungs stay comfortably cool with a solar fan in the attic that draws warm air up and expels it through vents, their tradewind-friendly original windows and two small Energy Star air conditioners, “which we hardly ever use.” A single solar panel on their roof is just for water heating,

Faulkner said the green benefits of preserving an existing home, rather than demolishing and building new, can’t be overemphasized. “Old buildings embody energy and carbon that was extracted, processed, transported and used to build them in the first place,” she said. They sequester carbon and keep it from warming the planet’s atmosphere.

Kept standing and intact, old homes, like old-growth forests, provide more than shelter.