Household appliances and home electronics contribute a sizable portion of your monthly electric bills (up to 20% according to the US Department of Energy). Daily life without the everyday usage of appliances wouldn’t be easy and it is common to overlook the vast amount of energy appliances consume daily.
It is without question that older appliances are far less efficient and consume more energy than the new models of today. Appliances that are over 15 years old can use up to 4 times the power of a comparable appliances manufactured today.
With the rise of the Energy Star program, manufacturers are producing products that use 20-30 percent less energy than required by federal standards. By doing this, appliances that beat the Federal standards are able to obtain an Energy Star rating.
The more things change, the more they stay the same. So it is with refrigerator energy use. The First Wave of mass-produced wave of refrigerators, with the characteristic compressor on top, used about 400 kWh of electricity annually.
The Second Wave “energy hogs” of 1955-1975 peaked at an average of 1,800 kWh. By the mid 1990’s, the “energy conscious” Third Wave lowered consumption to 1,000 kWh. Finally, by 2010 refrigerators used an estimated of 475 kWh… a number close to their 1940s ancestors.
Of course things have progressed. The modern refrigerators have three times the space of the old compressor tops, plus a freezer.
The practical application of this little history lesson is to replace your refrigerator if it was made before 1990 for the energy savings (and also because the nominal refrigerator lifespan is 15 years). You could get a 5-15% annual return on your $1,000 investment in a replacement. The older your refrigerator, the greater are the savings, and the more it needs replacement anyway.
How did the “energy hog” fridges become energy conscious? Government regulation forced the hands of the engineers who designed compressors, with more efficient motors and ways to shed the waste heat generated by squeezing refrigerant. They also added lots of foam insulation, adjusted the energy-using defrost cycles, and improved the interior circulating fan.
Consumers can save energy by buying refrigerators without through the door icemakers and water chillers. The provision of a ventilating air space, extending around the sides and back of the refrigerator is another energy saver. The air space supplies cool air to make the compressor operate more efficiently and keep the sides of the refrigerator cool.
The refrigerator configuration also matters. The “Energy-Guide” tags reveal that a “top-freezer” model uses more than 10% less energy than a “side-by-side” model of comparable size. The Energy Star label is also a valuable guide to purchasing an energy-frugal fridge.
Most dishwashers manufactured since 1994 use 7 to 10 gallons of water per cycle, while older machines use 8 to15 gallons. New dishwasher designs have reduced water use by including more-efficient washing cycles and controls that allow you to tailor each wash to the specific characteristics of the load.
ENERGY STAR dishwashers use 6 gallons or less per cycle. Surprisingly, dishwashers use less water than hand-washing if the dishes loaded into the machine are only scraped and not pre-rinsed.
Approximately 80% of the energy used by dishwashers goes toward heating the water. Booster heaters in the dishwasher heat the incoming hot household water (usually 120o F) to the 140o F required for efficient washing. Using water at 120o instead of 140o saves energy. For every 10 degrees a water heater’s thermostat is lowered, the water-heating bill drops by up to 13 percent.
ENERGY STAR dishwashers uses 1,800 gallons per year less of incoming hot water, which would require 14 therms of natural gas or 280 kWh of electricity to heat. In addition, ENERGY STAR dishwashers save 0.5 kilowatt hour (kWh) of operating electricity for each load as compared with a conventional dishwasher.
A conventional top-loading clothes washer with a central agitator uses around 40 gallons of water per load. By contrast front-loading washers, which don’t have a central agitator and are loaded through a door on the front of the machine, use around 20 gallons. By using less water front loaders also require less detergent.
Wash-water heating accounts for 85 to 90 percent of the electricity needed to do an average load of laundry. Front-loaders use half the hot water of a top-loader.
The process of spinning clothes on a horizontal axis of a front-loader consumes nearly 50 percent less energy than is required by top-loading machines. In addition, front-loaders spin more water out of the clothes, which means that they also save on the energy needed to dry the clothes.
Clothes washers use 20% of all interior water use. Replacement of top-loading machine with a front-loading machine could lower annual water usage from 14.000 to 7,000 gallons annually: a 10 % reduction of all interior use.
Annual energy savings of 300-600 kWh or more could be realized by replacing a 10-year-old clothes washer with an ENERGY STAR qualified model. Dollar savings for hot water heating and electricity to run the machine are in the range of $45 to $90 annually.
A pool pump typically uses 3,000 to 4,000 kWh of electricity for year round operation in Florida. It is the second biggest energy hog after your air conditioner accounting for 15% of a home’s energy budget.
A variable speed pool pump can trim two-thirds off this usage. Typical savings of 2,500 kWh and $250 per year make the switch to a variable-speed pool pump a no-brainer!
A variable speed pump has a permanent magnet motor like that of a hybrid car, and is 30% more efficient than an old-fashioned pump. Unlike a single-speed pump, it delivers only the gallons of water per minute (gpm) needed do each pool task, i.e., water heating, cleaning, chemical mixing, or water filtration. In addition, a variable speed pump is quieter, lasts longer and is easier to maintain.
Why can a variable speed pool pump save so much electricity? It comes down to an arcane law of physics. Doubling the gpm pumping rate increases the piping flow resistance by 8 times! Which means for every doubling of pumping rate 8 times more electricity is needed.
For example, if 16.5 gpm, low-speed pumping of uses 33 watts of power; 32 gpm medium-speed will use 250 watts; and, 66 gpm high-speed 2,000 watts. The corresponding percentages of power demand are 3.5%, 12.5% and 100%.
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