By Jan TenBruggencate
Advertiser Columnist

There's an amazing array of ways to heat water for domestic use.

For most, it's something we never think about. Somewhere in the house, there's a closet or vented room with a water tank heated by an electric coil, a gas burner or solar panels on the roof.

But those systems, while perhaps the most common, are hardly the only ones at work in the Islands. Some of the alternatives are rustic, though most work just fine.

In many parts of the world, instantaneous water heaters are common.

Unlike the standard Hawai'i systems, these have no storage tanks. When the hot water is turned on, a flame ignites under a tangle of copper tubing. The water enters the tubing cold and comes out hot — and it stays hot until you turn off the water or you run out of gas.

A friend with a rural home had a homemade version. He tells of fitting a coil of copper tubing inside an old oil drum. He'd use junk mail as fuel for a fire inside the drum. He said that the mail heated up the water in the tubing enough that he could bathe comfortably. I assume he took short showers.

I remember seeing a remarkably simple system once at a Big Island ranch house. It used a gas water heater, but the gas connections were abandoned.

The tank was set up on bricks about eight feet from the cabin, connected by two pipes to the cabin's internal plumbing. Cowboys simply built a wood fire under the tank, and the heat rose through the vent in the middle of the tank, heating the water. Thus, high on the chilly side of one of the island's volcanoes, there was a hot shower at the end of a dusty day working cattle.

On another island, I saw a country home where an old water tank was put on its side. The owners each afternoon would build a small fire under the middle of the tank with the day's junk mail and scrap wood, heating enough water for a shower and to wash the dishes.

There are mountain cabins with water pipes running along the back of the fireplaces. Each night's wood fires would provide the cabin dwellers with dry heat and hot water.

Many older Hawai'i homes have early versions of the solar water heaters now sold commercially. Many of these were assembled by plantation plumbers out of available parts, and they often used galvanized iron pipes inside glass-covered collectors. The copper pipe the modern systems use works better, but it wasn't readily or cheaply available.

Plantation welders also regularly put together wood-burning water heaters, with a small firebox below and a tank above. It was often the kids' job to gather sticks and paper to heat the water for the family's evening bathing.

It was one chore you didn't ignore, because of the chilling consequences.

Jan TenBruggencate is the Kaua'i bureau chief and its science and environment writer. Reach him at (808) 245-3074 or jant@honoluluadvertiser.com.