ELECTRICAL ENERGY SAVINGS – Easy, Low Cost Ways of Reducing Electrical Consumption
Overview: The average household electrical consumption is about 600 kWh (kilowatt-hours) a month, or 7200 kWh per year. You may be below or above that number depending on the kind of electrical appliances and lighting you have and how much you use them. If you have electric hot water, electric heating, or central air conditioning, you will likely be above this average.
The kWh (kilowatt-hour or kW-hr) is a measure of electrical energy use, and is what your electrical meter measures. It is found by multiplying the power of the appliance in kilowatts times the hours of use. For example, a 1500 watt or1.5 kW microwave oven used for 3 hours would use 4.5 kilowatt-hours (often written kWh).
The power rating of most appliances may be found on a tag on the appliance. It is sometimes given in watts instead of kilowatts. To change watts into kilowatts, just divide watts by 1000. A 25-watt light bulb is just 25/1000 or 0.025 kW. Sometimes you might find volts and amps on the tag and not watts. Just multiply those together to get the watts. For example, 120 volts and 3 amps is the same as 360 watts or 360/1000 = 0.36 kW.
You can find your electrical consumption by going to your utility web site (www.oru.com) and logging on with your customer service number. You will find the past two years of usage given on a monthly basis. The total price you pay is the sum of the supplier charges (production of electricity), delivery charges (O&R) and various other charges. If you divide the cost of a monthly bill by the number of kWh used, you will get the overall cost per kWh. It is slightly different for each customer since the cost depends partly on the total usage. In our region, it is currently about 17 cents per kWh for residential customers. Your usage each month will vary depending upon your use of particular appliances (summer peaking from air conditioning, pool pump use, etc.; winter peaking from electrical heating, warm air heat distribution, more lighting, etc.). The spring and fall bills (April or May, October) typically show little summer or winter peaking use, and reflect your base load electrical use (your everyday appliance use and lighting).
Reduce Parasitic or Vampire Loads: Many appliances like computers, televisions, DVD’s, stereos, etc. still use some power consumption when they are nominally turned off, but the power cord is still plugged in. Certain TV peripherals are particularly bad: DVR or TiVo 37 watts, Digital Cable Box -26 watts, Satellite Receiver – 12 watts, Analog Cable Box – 10 watts (Consumer Guide to Home Energy Savings). Surveys have found that many homes use 50 watts continuously from these devices even though they are not in use. Some households use a lot more. 50 watts of parasitic power over a year will use 0.050 kW x 8760 hours or 438 kWh of electricity a year, and, at 20 cents per kWh, cost you $87.60. If you used an average household consumption of 7200 kWh per year, removing a parasitic load of 50 watts would save approximately 6% of your electricity bill for the year.
- An easy way to ensure that the consumption is really zero when they are off is to plug the device and the peripherals into a power strip which is turned off when you are finished using the device. Many power strips also provide surge protection as well so they are a worthwhile investment to protect your appliances from damage.
- Likewise, cell phone chargers should be unplugged when not in use. If they feel slightly warm to the touch when the phone is unplugged, they are consuming power for no benefit.
- If you use your printer rarely while you are on the computer, don’t plug it in to a power strip. It will use less energy if you turn it on only when you print, and then turn it off. Otherwise, just plug it into the power strip.
- Many people just buy a power strip and plug those types of appliances listed above into them. If you would like to measure exactly what the parasitic power load is for each appliance, you can use a power-measuring device (one brand is called Kill-a-Watt). The Albert Wisner Public Library has several of these meters that you can borrow for a few days to measure your parasitic loads. Even though a particular parasitic load may seem small (say 10 watts), it is on continuously for the year and uses a lot of electricity.
Reduce Electrical Lighting Loads: Electrical lighting typically uses 10-20% of your overall electrical consumption. For the average household (7200 kWh per year), this would amount to 720 to 1440 kWh per year, costing $144 to $288 (at 20 cents per kWh). There are several actions you can take to reduce this energy use.
- Turn off lights when you leave a room. Just light areas that are being used. Use task lighting when possible. You can also install sensors that respond to motion or infrared so the lights will automatically go out when there is no activity or person in the room.
- Replacing incandescent lights with fluorescent lights can reduce the lighting energy consumption by 75% since fluorescent lights are 4 times as efficient as incandescent bulbs. It is most effective to replace those incandescent lights that are in use at least for 3 or 4 hours a day. A single 100-watt incandescent bulb, used 4 hours per day, and replaced by a 25-watt CFL (compact fluorescent lamp) would save 109.5 kWh a year, and save $21.90. Replacing just 4 such bulbs would save 438 kWh, $87.60, and about 6% of the average household consumption of 7200 kWh per year.
- Replace halogen torchiere lamps with an Energy Star fluorescent lamp. The high wattage halogen bulbs (300-600 watts) pose a fire safety hazard, and were banned in 2006, although some may still be sold today.
- If you use outdoor lighting, consider installing more efficient lighting (Mercury vapor bulbs are less efficient than high-pressure sodium and metal halide bulbs), or determine whether most outdoor lighting is needed at all. You can also use controls: motion, infrared sensors, and time and light sensing controls to minimize electricity consumption. Sometimes CFL’s are appropriate for outdoors, but be sure the bulb is rated for outdoor use (a regular CFL will be dim at low temperatures). A single 100-watt bulb left on 12 hours a day (average nighttime hours) uses 438 kWh a year, and costs $87.60 to operate.
- T-10 (2″ diameter) fluorescent bulbs are less efficient than T-8 (1″ diameter) or T-5 (3/4″ diameter) bulbs. Consider using T-8’s and T-5’s where possible. Better fixtures that are designed for fluorescent bulbs will allow more light to reach where it’s needed also can make big improvements in lighting efficiency.
- Fluorescent lighting will provide high quality lighting provided that you select the bulbs carefully. Go to a lighting store with many bulbs displayed and lit so you can chose the appropriate size and color which varies from warm white to daylight (cool white). Generally, the lower the K temperature on the box, the more the bulb resembles the yellowish light given off by incandescent bulbs (See chart below). Be sure to buy bulbs with electronic ballasts (they will not flicker). Bulbs with Energy Star designations will have the most information about the bulb and its performance, and will generally assure the highest quality.
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Bulb Color Temperature (K) Meaning
Warm White 2700 K Yellow light (candle flame) Closest to incandescent light
Soft White 2800 K Similar to incandescent light
Bright white 3000 K Neutral white or medium white light
Cool white 4100 K Clean, bright white light
Daylight 5300 K Sunlight on a bright day (bluest light)
*Incandescent bulbs contain some mercury and should not be disposed of in the garbage, but should be recycled. Home Depot offers free recycling for CFLs. The electricity saved by CFLs actually reduces the mercury in the environment because most electricity is produced by coal-fired plants whose emissions are the chief source of mercury.
Reduce Large Appliance Loads: When electrical appliances wear out, replacing them with new energy efficient ones can lead to major electrical savings. This is particularly true for major appliances such as refrigerators, freezers, clothes washers, and dishwashers.
- If your refrigerator is more than 10 years old, you might compare its electrical use with a highly efficient new Energy Star refrigerator. (See www.energystar.gov.) For example, an old refrigerator at 150 kWh per month could be replaced with one using 30 kWh per month. The savings over the year are 1440 kWh or $288. You might be able to pay back the total cost of a new refrigerator in less than 3 years just with the savings alone. If you use the average yearly household usage of 7200 kWh, this action would give a 20% reduction in your total electrical bill.
- Don’t keep old refrigerators and freezers running if you use them only occasionally.
- For dishwashers, use air dry instead of heat dry.
- You should plan your replacement appliance choice before the old one breaks so you can act immediately to get a new energy efficient one delivered. Also realize that the current Energy Star ratings for refrigerators generally do not include the electricity used by an icemaker, which can be substantial.
Reduce the Pool Pump Load: Outdoor pool pumps average about 1500 kWh per year, and cost $300 to run. They generally do not have to run continuously. Often these pumps can be put on a timer and run less than 1/3 of the time with equivalent results. This could save 1000 kWh, or $200 per season.
Reduce the Electrical Dryer Load: Electrical clothes dryers use large amounts of electricity over the year. A new electrical dryer will not be substantially more efficient than an old one (although it might have better controls – for example, shutting off when the clothes reach a certain dryness).
- If you have the option of using a gas dryer, you might consider how much you would save by replacing the electrical dryer with a gas dryer. Incentives may be available for this switch. (see Resources section below).
- If you dry one load of clothes per day (1 hour drying time), an electric dryer will use about 1000 kWh over the year at a cost of $200. If you use a clothesline (the solar clothes dryer) for 8 months of the year, you will save about 666 kWh or $133. If you used the average household consumption of 7200 kWh per year, you would obtain electrical savings of 9.3%. Drying clothes outside can also work in the winter if you choose your days carefully, and hang them out early. In this case, you save 14% of your electrical load.
Reduce the Air Conditioning Load: A 12,000 Btu/hr room air conditioner operated for 6 hours per day uses about 216 kWh per month, costing about $43. A central air conditioner uses about 648 kWh per month, costing about $130. From May to October, the energy use can be substantial. The less you need to operate the air conditioner, the greater the savings.
- Run the cooling thermostat at as high a value as possible. The standard recommendation is 78 degrees F. For each degree that you raise the thermostat from its current setting, you can save about 3% of the air conditioning load. For example, raising the temperature from 72 to 75 degrees can save 9% of the air conditioning load.
- Run an interior fan (ceiling or portable) that circulates air directly on you. The cooling effect can be the same as dropping the temperature 5 degrees. Use this in conjunction with AC thermostat adjustment. Keep windows shut when you operate the AC or interior fans.
- Do not operate air conditioners when no one is home. Consider a programmable thermostat that turns it on a short time before you arrive.
- Use a window fan to bring in cool air early in the morning, and then shut the windows. Likewise, run the fan again in the evening when the temperatures outside drop.
- Reduce unwanted solar heat gains, particularly from poorly shaded windows on the east, west and south sides of the house. Trees, window reflectors, window films, overhangs, etc. can block out unwanted heat.
- Reduce other heat gains in the daytime. Don’t operate optional major appliances if possible. Use minimal lighting. You are running the AC more to get rid of this heat.