Six months after Ann and James Kinser moved into their new home, they realized they made a mistake.

So the Kinsers did what mailorder customers typically do when they order the wrong size - they shipped the house back and got a bigger one.

The exchange was eased by the fact the Kinser home was a manufactured, not site-built, house.

That first house had about 900 square feet of living space. The Kinsers thought that would be enough, since their five children were grown up and out on their own. The 16-by-60-foot home proved too small, however, so they sent it back to Home-Mart Inc. in Tulsa and ordered a 32 -by-60. "We do a lot of entertaining, so we needed more room," Ann Kinser said during an interview in her living room. "(Home-Mart) just really took good care of us, They stand behind their merchandise."

Within a few months, their new house was ready and rolling down the highway toward the Kinserís lot, almost 75 miles south of Tulsa. The Kinsers were part of the caravan. "Thatís an odd feeling, going 65mph and passing your house going almost the same speed," Ann Kinser said.

Experts say changes in construction of manufactured homes has helped turn them into the, fastest-growing segment of the housing industry.

Todayís mobile homes must home meet federal building and safety standards and the architectural designs are similar to site-built houses. That means cities and towns that once relegated the homes to rural trailer parks now permit them in neighborhoods beside conventional buildings.

Because the houses are factory-built, buyers can save time and money compared with homes built on site. In 1993, prices ranged from $21,900 for a single-section home to $39,600 for a multisection home.

The Kinsers spent a year researching various options before they decided to buy a mobile, or manufactured, home. They paid $52,000 for their dream house.

Since 95 percent of buyers turn the mobile homes into permanent buildings, the industry calls them "manufactured."

"Itís just like ordering a regular house, only itís going to be delivered," said Ann Kinser. Typically, the dealer takes care of inspections and installation so homeowner does not have to deal with several contractors, she said.

According to the 1990 U.S. Census, more than one out of 10 Oklahomans - in excess of 264,000 people - lived in manufactured houses.

By the end of 1994, shipments of manufactured homes to Oklahoma reached 3,877 homes - greater than a 40 percent increase over 1993 sales and more than double the 1992 shipments.

"We now make up 30 percent of the housing market in Oklahoma," said Deanna Fields, executive director of Manufactured Housing Association of Oklahoma.

Tulsa is the biggest market in the state for mobile homes, she said.

"Retailers cannot keep them on their lots. They are selling fast due to the quality and affordability," Fields said.

In 1994, manufactured homes made up almost one-third of new single family housing starts in Oklahoma, according to the association.

The biggest retailer was Home-Mart Inc. in Tulsa.

There are more than 24 mobile home parks in the Tulsa metro area, but most Home-Mart customers buy houses to put on rural lots, said owner Doug Gorman.

Though many people think of manufactured homes as "tornado bait," those who live in newer models especial1y consider them relatively safe, Gorman said.

Very few buildings can withstand a direct hit from a twister, he noted. Mobile homes come with hurricane tie-downs and factory-installed steel straps to anchor the buildings. The Department of Housing and Urban worth Development allows homeowners to tie down the floor while some locales, such as Tulsa, require the straps go over the roof, Gorman said.

Eighty percent of Home-Martís sales are special orders, he said. Whirlpool tubs, which cost an extra $500 each; fireplaces, dishwashers, frost-free refrigerators, and decks are popular features in the Tulsa metro area market, this German said.

Ann Kinser said she chose a kitchen floor plan that provided a view into the dining room and living room so she could chat with guests while she cooked a meal. The Kinsers opted for plusher carpeting than the standard that came with the house model they chose. They also replaced the 32-gallon hot water heater with a 5O-gallon version.

"We have better insulation than most homes," she said. "Our utility bills are half of what the other homes are." The highest electric bill last summer was $105, she said. The Kinsers expect to get through the winter and a year of cooking on 300 gallons of propane.

Sheet rock walls covered with easy-to-clean vinyl is one,of severa1 features in the house that make it ideal for a busy couple like the Kinsers.

"Easy maintenance is one of the things youíll find," Ann Rinser said as she showed off the master bedroom and bath.

"Most people that come into this donít realize theyíre in a manufactured home", sheísaid.