DEAR TIM: A new dishwasher is in my future. While out shopping, I noticed a big difference in price. Also, it appears that computers have now invaded these appliances. How can sophisticated electronics help clean dishes? Are there quiet dishwashers? Is it possible for the average housewife to install a dishwasher? A. D.

DEAR A. D.: Yes, the microchip has infiltrated dishwashers. The microprocessors are connected to sensing devices. The electronic devices attempt to minimize the amount of energy and water that is used to clean your dishes. At this point in time, not all manufacturers are charting the same course. Some manufacturers feel the computerized machines may not do the job.

The electronic devices in the machines are very sophisticated. Some contain an electric eye which looks at how much dirt is in the circulating water lines. The dishwasher extends the cleaning cycle until it thinks the dishes are clean. Other machines have sensors that can detect the amount of dishwashing soap. If it thinks you goofed by not adding a sufficient amount, it raises the temperature of the wash water. Other sensors detect the washer arm rotation. If it is blocked by a fallen glass or plate, it adjusts the washer arm rotation.

Some models spy on your household habits. They memorize how many times you open and close the dishwasher door before running the machine. If hours pass, then it knows there is a good chance dried food will be present when it is time to go to work. The machine automatically increases the wash time and water temperature.

Some of these machines are pricey. They can approach $800 in cost. Energy savings may not pay for the difference in price from an non-electronic model. You must do the mathematics yourself to determine what the payback will be. Remember, price can often be a gauge of overall quality. If a machine contains inferior parts and less of them, it can often sell for less.

Noise is a major concern with most consumers who purchase dishwashers. Most manufacturers are going to great lengths to reduce unwanted noise. They do this by reducing vibrations. This can be achieved by increasing the sound deadening insulation in the door and around the tub. Precision electric motors and pumps are used that produce fewer vibrations. The extensive use of rubber mounting grommets can help. They isolate a vibrating pump or motor from the main body of the dishwasher.

Do you know how to turn off the circuit breaker that powers your dishwasher? Great! Get your adjustable opened end wrench, several screwdrivers, and some pipe dope. Take 30 minutes and carefully read the installation manual.

Turn off the electric power that feeds the dishwasher. Now, turn off the water line that supplies the machine. Remove the lower front panel to access all of the necessary, electric, water, and drain connections. Once you have disconnected these items, open the door to the dishwasher. You should see two screws that attach the dishwasher to the countertop. Remove these and the dishwasher should slide out. Now, install the new dishwasher and do everything I just said but only backwards. Be sure to check with your local plumbing department first. Some states have highly restrictive plumbing codes that will not allow homeowner installations.