Somehow, houses have failed to keep pace with a computerized, gadget-crazed world where car dashboards can talk and robots do walk.

But, apparently, the time has come.

Home-control computers that turn on the lights, water the lawn, start the coffee pot, operate the furnace and the burglar alarm, and keep the house perking along while you're away are on the market at prices ranging from $350 to more than $3,000.

And a homeowner who forgets to turn down the furnace or activate the burglar alarm before leaving on a trip can telephone the computer and issue the instructions.

These and other wonders are available in a variety of gadgets designed to turn an ordinary house into a home of the future and new wrinkles are being added almost monthly, say industry experts. One of the most ambitious efforts under way is a Smart House Project involving research and financial contributions from utility companies, manufacturers, trade associations and government agencies, and coordinated by the National Association of Home Builders. The project's researchers hope to have a system far more sophisticated than anything available now ready for production by late 1987, according to Martin L. Brown, of the NAHB Research Foundation.

Before getting swept away by the exciting prospect of a computerized house, however, a homeowner should consider carefully whether the system being considered will do enough work around the house to make it worth the price. After all, a $5 timer will turn lights on and off at predetermined times, and some appliances already are equipped with microprocessors that can control their functions.

"The control computer is only really helpful where one saves money, or saves personal time," said Bill Hawkins, computer editor for Popular Science magazine, who built his own home-control device five years ago when such systems were rare. "If . . . you spend 15 minutes [setting the computer] to turn on a light bulb, it's a novelty at first but it quickly wears off."

At this point in development, "there isn't a lot a computer can do," Hawkins said. "Smart appliances and smart houses . . . will grow up together" as microprocessors are used more widely in appliances and home-control computers are improved, he believes.

Some homeowners agree that high-tech houses have a long way to go. A Southeast Washington resident said her "automatic outdoor light switches . . . have such a flashy reset system that a neighbor once called to make sure I wasn't signaling for help." She concluded that "smart houses are never quite as smart as even the dumbest owners."

Some experts say the most prac-tical home-controller at present is a "dedicated" system, which does nothing but direct functions in the house. It is more practical and less expensive than a complete system tied in to a computer that can be put to other uses besides home control. In most cases the computer cannot do two things at once. If you want to balance your checkbook or your children want to do their homework on the computer, you first have to tell it to stop minding the house.

One such "dedicated" device is General Electric's HomeMinder, which can be connected to a house's existing electrical and telephone wiring. It is available in two versions, a "stand-alone unit" that can be hooked into any television set, and a controller that is built into the back of a 25-inch television set, at prices of about $500 and $1,200, respectively, said GE spokesman R. K. Freedman.

Last month Ryan Homes Inc. began providing as standard equipment the GE stand-alone unit in all the homes the company builds in 25 markets in Texas and the eastern part of the United States, including the Washington area. Ryan houses now sell for prices ranging from $50,000 to $130,000, and the addition of the home-control unit "won't always" increase the cost, said John O'Neill, market manager for the Washington area.

A Ryan Homes official in Pittsburgh said an extra charge for the computer will not be added to the cost of a house, but that most home prices went up by $200 to $300 last month to cover costs of the computer and new building materials.

With the computer unit, "you can control your entire home from your easy chair by your TV set," said Freedman. A push of a button brings up on the television screen a chart with pictures that will tell you whether the lights are on in another part of the house or whether the kids left on the radio in their bedroom, allows you to turn on the coffee pot or the outside lights, and operate anything else that is hooked into the computer.

For vacation protection, the unit will give your house a lived-in look by turning lights and radios on and off in mornings and evenings, and vary the pattern from day to day.

An owner can use a push-button phone to do most of the same things, and leave messages on the television screen as well.

Many of the home-control computers now available can be directed via telephone by their owners, who use a password and punch out instructions on the phone buttons. Most systems, however, are designed to perform a limited number of functions by telephone, said Eric Davidson, marketing director for HyperTek Inc.

Davidson's company makes a sophisticated, and expensive, home-control system that includes security, fire-safety and lighting controls, energy management and vacation protection in its basic package. The sequence of events set off when fire triggers a smoke detector is an example of what the system, dubbed HomeBrain, will do: It turns on lights to help residents find their way out of the house, flashes outside lights to signal the fire department, sets off sirens, turns off heating and ventilation systems and triggers a phone call to the fire department.

The HomeBrain's standard package of hardware costs slightly more than $2,100, and the installation can range from $500 to $1,500. With additional equipment it also can perform other home chores.

The smart house of the future being developed under NAHB's direction will have a computer system that can do several things at once, according to Brown. Designed to be built into a house during construction, the system will control all the jobs performed by current devices and more. Among its talents will be an "occupant detector" that can detect a person in the house, know whether the person is an adult or a child, and can distinguish an animal from a human, said Brown.

"Therefore, you can have routines which allow you control" in situations involving people. "For example, if the occupant detector is on for [interior] security purposes at night, the dog won't trip it."

An innovation that promises increased economy and safety will be the use of "closed-loop power," according to David J. MacFadyen, director of the project. Any piece of equipment receiving power will be able to "identify the power it needs, and if it is not receiving the right amount, the controller shuts it down."

A single cable will bring in the power and signal communications for the entire home, MacFadyen said. The electrical power will be converted from alternating current to direct, which eliminates most electrical shock and fire dangers and powers most appliances more efficiently, he said.