Electricity rates are at their highest level ever, and since air conditioning is often a building's single biggest user of electrical power, there is increasing interest in controlling the cost of keeping cool.

That's for economic and environmental reasons.

One solution is fans, which use a fraction of the electricity of air conditioners.

Super-insulating roofs and walls can allow homes to be cooled with the smallest air conditioners possible.

Another alternative is the one proposed by Honolulu Seawater Air Conditioning, which is working on a plan to use cold deep ocean water to cool downtown Honolulu buildings — at a substantial savings in power use.

For residential properties, perhaps the most elegant solution is to design homes so they self-ventilate.

The late Honolulu architect Vladimir Ossipoff was famous for self-cooled homes with deep overhangs and open floor plans. He told me once that he mourned the replacement of the small Hawaiian house on a large lot, because the tendency to build massive homes that nearly covered their lots meant there was not enough open space to admit the trade winds into the homes.

Kaua'i architect Skylar Brown has designed a class of homes he calls Natvent, for natural ventilation, which is created to remove solar heat before it can radiate into living spaces, and to passively provide continuous air flow. The designs have an open interior that feeds to a central atrium, which draws air up and out. Each room opens to the atrium.

The key to the system is a complex roof design that performs multiple functions, but does not add much to the home's cost, he said.

"Roofs are the cheapest thing to build," he said.

The home designs are square. The ventilation will work with the wind blowing from any direction, and they will continue to draw air through them in still weather. One-story designs run from one bedroom to three, and 1,500 to 2,300 square feet.

"The shape of the building acts to ventilate the building," Brown said. "The advantage of a square floor plan is the ease of construction."

From a distance, a model of Brown's one-story house has a nod to traditional Hawai'i architecture, with a central roof that appears to float atop a perimeter roof, and a change in roof pitch from the central to the perimeter sections. Brown has a curved roof on a two-story Natvent house design. For more information, see www.skylarbrown.com.

If you have a question or concern about the Hawaiian environment, drop a note to Jan TenBruggencate at P.O. Box 524, Lihu'e, HI 96766 or jant@honoluluadvertiser.com. Or call him at (808) 245-3074.