QUESTION: My old dishwasher is noisy and doesn't always clean completely. How well do the new efficient, super-quiet models clean? What are some of the new convenience and efficiency features to consider?
ANSWER: There are many new super-quiet dishwashers that provide very effective cleaning. Some models cost less than $40 per year to operate using an electric water heater and even less with a gas water heater.
The newest and most efficient features are electronic "brains" to select and fine tune the cycles automatically, super-hot sanitizing cycles and high-quality internal filters for better cleaning with less hot water.
The most energy efficient and quiet dishwashers use a two-pump system. By using two single-direction pumps instead of one large reversing pump, the water reservoir can be smaller. This cuts hot water usage by 40% to only 5.3 gallons on the normal cycle.
Two-pump systems are inherently quieter. One single-direction pump, with a quiet quick-start feature, is used for the high pressure washing spray. Another small quiet pump is used to drain the water after each cycle. Two-pump systems do not require the extra valving of a single reversing pump.
Insulation level is important for efficiency and noise reduction. Several of the well insulated single-pump models are quiet too. Multiple layers of asphalt/felt/foil insulation or fiberglass batt wraps are effective. Motors and pumps mounted to the base pan instead of the tank also reduce noise.
One new efficient model uses sensors and a computer brain (Intellisense) to automatically measure how dirty the dishes are. The electrical conductivity of the water, its cloudiness, its temperature and the spray arm rotation speed are continually measured by the brain.
The brain determines the minimum cycle time for cleaning and drying. It even remembers the last time you washed. If it has been more than a day, the brain assumes the food is dried on and uses a slightly longer cycle. The cycle can also be manually selected, like light/china, for example.
Many of the super-efficient European designs offer a super-hot sanitizing cycle. The water is heated by an internal heater to 165 degrees for a minimum wash cycle of 24 minutes. A final seven-minute rinse is also super-hot.
High quality filters, some self-cleaning, and built-in waste grinders improve cleaning. Multilevel spray wash systems, up to four levels from two rotating arms, require shorter wash cycles. One model uses two rotating mini-arms on the ends of the regular arm to insure every dish gets sprayed.
Write for Utility Bills Update No. 849 showing a buyer's guide of 21 quiet and efficient dishwasher manufacturers listing number of pumps, water usage, spray wash system, cycle/options, rack material, features and prices. Please mail $2 and a self-addressed envelope to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.
Should Thermostat Be Turned Up All at Once?
Q: I have a gas furnace with a manual wall thermostat. I set the temperature 10 degrees lower at night. When I set it up in the morning, should I increase it in steps over an hour or all at once.
A: With a gas or oil furnace, it doesn't make much difference in energy usage if you set it back up in several two-steps or all at once. It is more convenient to set it up the full 10 degrees initially. Consider purchasing an automatic clock setback thermostat for less than $50.
If you have a heat pump with backup electric heat, set it higher in several-degree steps. This keeps the backup heaters from coming on.
Letters and questions to Dulley, a Cincinnati-based engineering consultant, may be sent to James Dulley, Los Angeles Times, 6906 Royalgreen Drive, Cincinnati, Ohio 45244.