Leave a light on. The amount of money you'd save by turning off every 100-watt bulb the moment you left the room wouldn't even buy a cappuccino in these days of budding deregulation and rising energy prices. But if you're convinced you it's time to start saving money on your energy bills, it might be wise to rethink your temperature tolerance. Letting your house get a little cooler in the winter or a little warmer in the summer can save you a bundle. "Most of our customers have air conditioning. That alone in the peak months can cost a couple hundred dollars a month to operate," says Tony Pierce, senior engineer with Southern California Edison. The typical household keeps the thermostat set at 72 degrees in the summertime, adds Sheree McKenna, coordinator for Edison's in-home audit program. For every degree you hike that temperature, it saves you about 3% on the cooling portion of your energy bill, she says. So if you raise the indoor temperature to 78 degrees in the summer, you save 18% on that portion of your bill.

For a family spending $150 a month on air conditioning bills, that's a $27 monthly saving--enough to buy several new tank tops. If you're out of the house for most of the day, consider pushing the thermostat even higher, Pierce suggests. parts for ac unitAlthough the house won't feel quite as refreshing when you step in, for every hour that your 4-ton air conditioning unit doesn't run, a family that's used more than its "baseline" energy allotment will save $3.36. how much do new air conditioner units costOver a 20-workday month, that cuts your bill by $67. car a/c repair londonCan't stand a blast of hot air when you walk in the door? At least close your curtains on your east- and west-facing windows, McKenna says. That will keep direct sunlight from raising the temperature so much that the air conditioner must work overtime.

When it gets cold, throw on a sweater and keep the thermostat low--between 68 and 72 degrees, experts advise. That won't save you quite as much as it does to cut back on air conditioning, but it may save you from seeing a huge boost in your monthly gas bill. Rate hikes for natural gas are likely to boost consumer bills from an average of $50 a month to $75, says Ron Low, a spokesman for Pacific Gas & Electric Co. So make sure you do simple things to conserve energy, such as keeping your fireplace flue closed and your windows adequately caulked. Operating the washing machine and dishwasher add up, too--but not by much. Running the dishwasher every day costs you about $11 a month. Doing 20 loads of laundry each month costs between $5 and $16, depending on whether you've got electric or gas appliances and whether you're doing more cold- or hot-water washes. Using your gas oven an hour a day, 30 days a month, costs less than $3; so does the range. You can leave the computer and color monitor on 10 hours a day every day and it'll cost you about $5 a month.

Running your 27-inch TV four hours a day costs less than $2 a month. (, but the rates are based on an average of 11 cents per kilowatt hour, which includes subsidized rates. Your average is likely to be a bit more--usually 1 to 3 cents more per kilowatt hour.) Watching the energy efficiency of your appliances also makes some sense. It costs twice as much to operate a pre-1992 frost-free refrigerator than it does the comparable post-1992 model, according to PG&E. The monthly cost to operate an old 15-cubic-foot refrigerator amounts to roughly $20 each month, compared with about $10 for a newer 15-cubic-foot fridge. Can you assume that new appliances are all more energy-efficient than the old? Unfortunately, no, Pierce says. Many less expensive appliances are cheap because they're not energy-efficient. Anyone who knows about SEERs (seasonal energy-efficiency ratios) knows you save money when you buy cheap appliances but pay many times over when operating them. For instance, the minimum energy-efficiency standard for an air conditioning unit is 10 SEERs, but some units boast SEER ratios of 16 or 17 and thus are 60% to 70% more efficient than the minimum.

Even if you pay several hundred dollars more for the unit, you can expect it to pay for itself in decreased energy costs. The same can be said for simple lightbulbs, Pierce notes. Though turning off the lights may not save a ton of money, it does make sense to pay attention to the type of bulb you use. For instance, your typical incandescent lightbulb is highly energy-inefficient when compared with a compact fluorescent bulb. However, most people choose incandescent bulbs because they're cheap, about 50 or 60 cents per 60-watt bulb. Fluorescent lights, on the other hand, might cost $8 to $12 for a bulb that generates roughly the same amount of light. But the fluorescent consumes just 13 watts of electricity and often lasts 20 times as long. What will it save you to screw in those fluorescents instead of the incandescents? If you leave four 100-watt porch lights on for 10 hours a night, that'll cost you 40 cents a night. Four equally bright fluorescents will cost just 10 cents a night, Pierce says.

If you want those porch lights to be burning brightly 365 nights a year, fluorescents will save you nearly $110 a year. You also might consider signing up for a time-of-use program, which varies your electric rate based on what time of day you use the power. If you can shift the bulk of your electricity use to off-peak hours--usually nights and weekends--a time-of-use plan may make sense for you. I'm planning to install a 5 ton central AC. I'm deciding between a condensing unit that runs on 220V and a costlier unit that runs on 207Y three-phase. My understanding is that three-phase motors use less power, and that this is their primary advantage. But no one seems to be able to tell me how much less power. Without knowing that, it's hard for me to make a decision. I'm sure the answer is some form of "it depends," but can anyone give me a ballpark? Should I figure 10% less power consumption, or more like 50% less. Any guidance is greatly appreciated. Also, the wikipedia article on three-phase power claims that three-phase motors vibrate less.

Is this something I should care about? Will a three-phase motor therefore last longer than a single phase motor? electrical hvac air-conditioning energy-efficiency electric-motor If you have the condensers already selected, you should be able to get the two pieces of data you need to make a decision. 1) price increase for 3 phase condenser 2) operating power for single phase and 3 phase units. I suspect they will quote you that the two units consume the same amount of operating power. Yes, theory says 3 phase motors run smoother just like V8s run smoother than 4 cylinder engines. But the practical difference in motor life is something you will probably never see. One possible reason that a 5 ton unit is available in 3 phase is that the amperage is lower and thus you could save some money on the wiring cost. This comes at the cost of an extra circuit breaker. Think I'll chime in here and add my two cents to these other good answers. There are two components to the original question:

How much less power does will the 3 phase A/C compressor unit use? Longevity of three-phase motor versus single phase Motor Efficiency = Power Output / Power Input It takes a certain amount of power to run the compressor regardless of single or three phase power... this is the power output. The power input is what you are trying to minimize, thus you want to increase efficiency as much as possible. The trouble is this metric (efficiency) is a hidden combination the components inside the compressor unit (compressor, fans). It is not necessarily true (but it usually is true) that three phase is more efficient than single phase. I would look at the SEER rating which 'automatically' includes the motor efficiency for a better indicator of "cost to cool". Three-phase motors and compressors are generally more reliable than their single-phase couterparts. But like anything else, there is more to it than that one attribute. Using Philps' automotive engine example, a 4 cylinder Honda might be more reliable that that old smallblock V8.

Certainly less in the three-phase motor. And generally less vibration equals greater reliability. Three-phase motors have lots of starting torque and don't (typically) require any special circuitry to start (capacitors, centrifugal switches). And of course fewer components means fewer things to go wrong. Is disappointing that the three-phase equipment is more expensive. Almost always, three-phase motors are actually cheaper than an equivalent single-phase motor. 1hp = 756 watts 5hp = 3730 watts 3730 watts at 230 volts = 17 amps 3730 watts = 3730(watts) / (207(v) x 1.73) or 3730 / 358.11 = 10.4 amps. Three phase is 40% less amperage. There are other things to make this accurate, like motor efficiency and power factor. I used 1 for each. Another savings is that with the reduced amperage you can reduce your conductor size for your feeder. With the price of copper today that could help matters too. I used 5hp for no special reason, just a nice round number.

I suggest using three phase. The above example of 5hp at 240v = 3730 watts and 5hp at 207v three phase = 3730 watts is correct. You draw less amperage with three phase but with more added voltage. Power is power and you draw 3730 watts with either scenario. Your savings will come in the durability and longer life of a 3 phase motor. You will also reduce your feed supply conductor size but will have to add another pole to your breaker or disconnect switch and one more conductor too! By using a three phase motor you will also balance your load on your service and probably increase your power factor efficiency which your hydro utility probably charges you extra based on a lower one, (check your bill). The nod goes to three phase but only slightly. Pay hundreds more for a 3 phase not thousands. I have a 220 volt device (motor, dryer whatever... it makes little difference for this example). Single phase device draws 43 amps (43 x 220 = ~ 9460 Watts or 9.5 KW) Same unit with 3 phase draws 25 amps (25 x 220 =~ 5500 Watts or 5.5 KW)

*** The same amount of work is output with either unit despite the 3 phase using less power because it is more efficient. I currently pay $0.14 / KW and Run the unit 6 hours a day. Single phase costs me (9.5 x .14 x 6) per day to operate or ($6.65). Three phase costs me (5.5 x .14 x 6) per day to operate or ($4.62) a difference of $2.03/day. Therefore the difference in 1 year (5 days a week) is a yearly savings of $527.80. 208/120Y is cheaper for supplying condominiums because one neutral can carry the unbalanced loads of three ungrounded conductors. But for the consumer, the voltages difference of 208V vs 240V usually equates to the same overall wattage, with the only negligible concern being it takes longer for heating elements to reach their desired temperature. As for motors, whether or not they're more efficient is not a question, but rather if you'd notice that difference in your monthly power bill. That I would probably say no just because being a residential area.