One Of The risks in trying to sell a house is that any sort of deal you might make is subject to divine intervention. My parents recently made this discovery when, on the verge of unloading the big old house we all labored so long and hard to build, they received the news that their real estate agent had unexpectedly gone off to meet his maker.

The man who intended to buy the house had his heart set on it because of its superb paint job and the interesting way one goes about turning on and off lights there.

The lighting system is the work of a California firm called Touchplate Electro-Systems Inc. It is pure genius. From the master control panels in the kitchen and master bedroom, you can operate any light in the house. Not only can you switch lights out at will, the buttons light up to tell yoy which of them are on.

My father's great foresight in building this device into our house arose primarily because he was sick and tired of chasing around in his pajamas at bedtime turning out lights half a mile away. Also because he knew it would provide us kids with hours of fun.

For instance, you can sit at one of the control panels-with a few friends is best-and hear Sis going up the stairs. A light blinks on. Aha! She's in the bathroom. Wait a few seconds and "Click," you press the light out. A moment later, it goes back on. You turn it out. Then screams from the blinking lights, communicating like tiny interstellar voices, proved absolutely there was life elsewhere in the universe besides the kitchen. With an intercom system-all the better to hear the screams-it was a regular riot.

At the time, my father had no idea he was standing on the brink of the future. Yet, he was. Electronics wizards are poised and ready to completely change the way we go about managing a house.

Engineers are moving farther and farther away from "magic black box" technology. With the advent of the computer "chip", that tiny piece of gadgetry able to store thousands of pieces of information, the day of the Orwellian house hold may be here sooner than we think. Perhaps even by 1984. Men of science may ultimately develop a computerized house sitter that will automatically arrange all your lighting, heating, cooling, security and any electrical gadget you might desire to have hooked up to it.

What may be in store is:

A house armed with a computer programmed to make energy use totally efficient. The computer will allow appliances, such as hot-water heaters, furnaces, air conditioners, fans and lights, to run only when they are needed. Hooked up with sensing devices, it will detect when someone is in a room, raise the temperature and turn on the lights when a person enters and turn down the heat and switch off the lights when he leaves.

Sound like "Star Trek?" In fact, it is more like Ponderosa Steak House. Honeywell has a system there, and many others elsewhere, that may not be quite so sophisticated, but run electrical use with dictatorial zeal.

"We have them installed and working in the area," says Mike Pristas, an energy management specialist for Honeywell Inc. "They have a three-fold purpose. 'Demand control' limits the amount of electricity that is being used at any particular time to a preset level. The second one is 'duty cycling,' cycling loads [energy users] such as compressors, heat-ventilating/air conditioning, turning them off for so many minutes per hour to accumulate kilowatts-per-hour saving. And 'time-of-day-programming,' turning loads on and off as needed automatically."

During peak periods-lunch hour in a restaurant for instance-the system limits energy use to a certain level and turns off lights or appliances, such as a dishwasher, where they are not needed.

"This technology is on the market." Pristas said, "but not residential. It filters down from the big users to the home owners.

"The next generation," and what may end up in the home, he said, "is going to be a push-button chip. The same size as the (hand-held) calculator where you can push in when you want your heating to go on and off. They're going to apply this to other types of loads that you program yourself."

While total-management systems are not yet available for home use "that's where the technology is going."

General Electric has developed one of the first such devices for a pilot energy project in the Frederick, Md., area. GE is working with the local power company, Potomac Edison, to introduce a means of making energy use more efficient.

Home owners may see the results of this experiment, a computerized energy regulator, on store shelves in less than five years.

"It differs from a normal thermostat because it has 'Light Emitting Diode' (LED), the same as a display calculator," said Gene Krumnacher, manager of marketing for home-comfort control in GE's Charlottesville, Va., office. "Right now we're in a trial period for the utilities to prove that it will do what we say it will do. Some years down the road it may be sold in every place where you can buy a regular thermostat." Probably for less than $200, he said.

We call it a 'Smart Thermostat.' The computer (using chips) is about the size of a pin head. If the utility or the home owner desires, we have additional contacts to wire in hot-water heaters, swimming-pool pumps, etc."

You can also press a button to read the temperature or time. When the system is in trouble, the display says, "Help!"

"About 2 1/2 years ago I recognized we needed some means of controlling energy use," said Joseph R.Staley, manager of engineering application and research at Potomac Edison in Hagerstown. "And then we went to GE and asked them if they could build something like this in miniature.

"We currently have about 130 of these installed and expect to have about 300 by spring. Sixty of them have a magnetic tape to monitor [energy] savings."

These are in newly constructed homes around Frederick, where the power company also stood by to see that insulation was installed correctly, Staley said. The device is programmed according to weather conditions in the utility's service area.

"In wintertime, it preheats the house at 7 a.m. till 9 at four degrees above normal temperature (72, say, if "normal" is 68). Then the heat is turned off completely. There is no heat again until 2 p.m. Then the heat comes back on till it reaches normal, until 3 p.m. Then it preheats four degrees till 5," when it goes back down.

During reduced heating times, said Krumnacher, the device allows a "slope down," over which the home owner usually has no control. If the temperature goes beneath the slope, the computer initiates a "burst of heat" to bring it up. There is a panic button, just in case.

"the principle we're working on," said Staley, "is that everything in the house, like drapes and furniture and carpeting, acts as a 'heat sink' [heat storage]. This heat sink gives up temperature rather rapidly at first, then slowly as the temperature drops. The temperature may drop as much as seven or eight degrees, which is not extremely uncomfortable for a short period of time."

Staley said the project will run another year, with an initial report expected out this spring. GE is working on a similar project-to regulate air-conditioner use during utility peak hours-with Gulf Power in Pensacola, Fla.

One homeowner who appears to have taken the matter into his own hands is Ron Lavalle of Hudson, N.H. McGraw-Hill's new book, "Personal Computing: Hardware and Software Basics," quotes Lavalle as saying he installed a microprocessor on his wood-heating stove. "When his neighbors. . . lowered their thermostats to avoid a second month's gas bill of well over $100, he kept hid six-room home at a toasty 75 degress. His December gas bill for heating, cooking and water was only $29."

A thermal sensor in the stove's stack pipe tells the microprocessor when to open and close the damper, with the aid of a step motor, to control the speed at which the wood burns. When the fire is going out, "a low-wood alarm is activated. The signal beeps once a minute until the stove is loaded again."

Devices currently available to the average consumer-the "magic black boxes" -employ conventional electronic technology and are thuslimited in the things they can do. But you can buy timbers, thermostats, damper controlers and pilot light firers that regulate appliances such as water heaters, furnaces or swimming-pool pumps. Many of these energy saves also are eligible for federal income-tax credits.

Companies for years have sold clock-like thermostats, to replace your old one, that you set to turn the heat on and off periodically.

Honeywell is advertising a "Fuel Saver Thermostat" it claims can "tear 25 percent off your heating bill" by shutting down the furnace at night and turning it back up again in time for reveille. The thermostat costs about $125 completely installed.

In its 1979 catalogue, Sears, Roebuck & co. has introduced what it calls a "Home Electrical Control System." Similar in concept to the touchplate system, it plugs into wall outlets. It consists of a "command console" that can send signals to turn on, turn off, dim or brighten fixtures on 16 different frequencies.

By plugging lights or appliances into modules that receive the signals, you can control a virtually unlimited number of switches.

"Our marketing approach is security," said a Sears spokesman. If you hear a bump in the night, you can hit one button that turns on all the house lights. Otherwise it is mainly a convenience device aimed at those with fantasies of rolling over in bed in the morning, pushing a botton and turning on the coffee pot downstairs.

One drawback is that the buttons do not light up to tell you when a light is on. Also, it operates only small appliances, such as coffee pots, toasters blenders, etc.

The system costs $40 for the console, $15 for each appliance module and wall switch, $14 for lamp modules and $20 for a remote control unit, something like the hand-held sender that operates a television.

Meanwhile, the granddaddy of all-Touchplate-is still going strong, says owner and president R.G. Martinson. "We are absolutely swamped. We get hundreds of orders a week."

Touchplate started in 1946, when many electricians wouldn't go near it. Television personality Art Linkletter owned and ran the company until 1968. Now, "everybody's jumped on this bandwagon and there must be 200 little manufacturers making gadgets with microprocessors. They've taken the computer technology and reduced it down to small, inexpensive devices. . . like the calculator."

The Touchplate system is a money saver because of its monitoring capabilities and because it operates on low voltage. The switches run on 10 volts (eliminating need for heavy conduit and much electrician's time) and control lights through a relay box. An average household setup costs around $600 in new construction. Installing one in an old house would be much more expensive.

"We've had systems that are so unbelievable. They open sliding-glass doors, skylights. They run off photo cells," which, by the way, are available in many electrical-fixture stores and also regulate lightsautomatically-according to the amount of sunlight (cost about $10).

"The bulk of our business has grown in to energy conservation systems, mainly in commercial establishments," Martinson said. "In Buffalo, N.Y., we did the Erie County Health Center. That whole thing is done in low voltage. What we're doing is turning off lights automatically, either by computor or microprocessor or plain old time clocks."

Touchplate also has put together schemes for Northrop Corp., Douglas, Lockheed, IBM, Hughes and Reynolds Tobacco. They will draw up a design for you, free of charge, if you send your house plans to: 16530 Garfield Ave., Paramount, Calif., 90723.

Keep in mind, however, that not even computers always work as they should. Once you have your completely computerized, you can't forget the red light that goes over the mantel piece. In case you do not notice right off, the blinking red light means the computer, as they say, is "down." CAPTION: Illustration, no caption, by John Heinly for The Washington Post