There will be a new part of the Small World Group website soon. It will cover the operating model and actual performance of my new home in Tiburon, California, USA. Tiburon is one of the sunniest places in the USA and it has a temperate climate where it is rarely above 80F (27C) or below 45F (7C). The home has most of the technology to be “green”.
But key to me is can we go so low in carbon use to say that my family has a carbon neutral footprint? One of the key insights that I had read but never fully understood was how important it can be to track all of the electrical uses in the home. Today there are many “loads” that have some residual current flowing even when the device or service seems to be completely turned off. Some examples of these phantom loads are computers running screen savers, outside lighting that is on all night; more subtle ones include cable or satellite TV boxes that are on continually to provide instant service. Why are these so important? Let’s look at a few cases to help you understand better –
- Consider outside lighting that you may be using to feel safe or that is helpful to guests and visitors who arrive after dark. Suppose you have 8 lights each using only 60 watts each. That is a total of nearly 500 watts. if you use a sensor to have these turn on at night (i.e., the sensor detects when it is dark out) then you will typically use this 10 hours per day (average of summer and winter) and so you use about 5 KW-hrs per day or 150 KW-hrs per month. This would be 50% of what PG&E, our local electric power supplier calls a base load. All for lighting that is rarely of benefit. By exchanging these lights for compact fluorescents the power per bulb for the same light could drop by 75% so the monthly load would be perhaps 40 KW-hrs. But by putting the lights on a combination of light sensor (to know it is dark outside) and a motion detector (motion detectors enable the lights to turn on only when there is someone outside) as well you could cut this likely 99% so you would only use perhaps 1 KW-hr.
- Next let’s look at the CATV or satellite box that connects your television or display to the service provide’s entertainment. Today it typically has multiple memory devices. Some information is downloaded from the system into active computer memory to help it know channels and services available now and for the next 2 weeks. The “box” uses anywhere from 30-200 Watts continuously so again this device would account for between 1-5 KW-hrs of power per day or 30-60 KW-hrs per month. This one box can cost you 20% of the normal or low cost power from a provider like PG&E. A better answer is to decide when you actually watch TV and to either turn the entire system off manually or purchase a small timer outlet from your local hardware store. By using this device you could turn all of the home entertainment gear off from mid-night to perhaps 4 pm the next afternoon. This again would save 67% of the load and likely provide you with the same perceived level of service. Of course you would not tape an episode of “Law and Order” at 4 am in the morning.
- Another type of phantom load are personal computers and the equipment associated with them. If your internet service provider is either cable or the telephone company (DSL) you have a modem to send and receive data from the transmission wires or cable, you have a router to make the service available to multiple people or users in the home, then you have printers, computers and other devices that use this service. If your leave your computer on when you are not using it (there have been recommendations that this is “good” for the computer …) and even if you are using a “screen saver”, the computer gear probably has not been put in a low power state. So all of the above gear probably uses about 200 watts of power steadily. Again, this would be about 5 KW-hrs per day or about 150 KW-hrs per months. The simplest way to save here is to use the computer’s sleep mode. This will drop the computer’s power usage down by more than 95% but it will likely also turn off the display screen to a low power state as well. For the system I am using to write this my savings are about 140 watts. To go further, you would need to agree in your home that you are unlikely to need internet access certain hours of the day say from midnight to 6 am and from 9 am to 4 pm. Then you could put a timing switch (cost about $10 at any hardware store) to control the power to the power strip for those elements and save another 50-100 watts depending on the age and extent of your equipment.
As I have chased the phantom loads inside the remodeled home, our energy performance has substantially improved. But it requires discipline and some careful thinking through things. It is possible to make real mischief among teenagers, for example, who might be using the internet when you think they are not!
More on this later … and some real data as well.