x•s•v•toys (ex-es-iv-toyz or excessive toys): Exceeding a normal, usual, reasonable, or proper limit for the purchase of consumer electronics.

## The xsvtoys Energy Consumption Web Page - GO GREEN AND SAVE MONEY!

This project is dedicated to answer the questions: How much electricity is my [fill in toy of your choice] using and how much is it costing me?

These can be important questions when extra computers, televisions, etc. etc. are installed in the home, as is becoming more common. This is especially true if you happen to live in California, home of some of the highest electricity rates in the USA!

## Some basic introductory information.

The technical aspects of electricity and its usage in the home are well-documented so we won't go into unnecessary detail here. If you would like to know more, your favorite search engine should yield plenty. Try searching on "how does electricity work" or some such. Or to save you even that effort, try www.howstuffworks.com, this is a really good web site for such education.

The Voltage in the home (for USA) is 120 Volts AC. This is what is supplied by the power company. (The actual voltage isn't actually 120 most of the time, but its somewhere around there.) When plugged into the wall outlet's 120 volts, your various appliances and such consume electricity in the form of Current, which is measured in Amps. The Energy usage, or Power usage, is a function of the voltage multiplied by the amps, or Volt-Amps. This is basic physics 101!

power = voltage x current

So if a device uses 1 amp and its plugged into a voltage of 120, then its power is 1 x 120 = 120 volt-amps. A volt-amp is also known as a Watt.

Since the typical USA home has a bunch of consumer goods gobbling up electricity, lots of watts get used. So rather than deal with large numbers, like saying "This widget used 56,000 watts", it is common to re-factor this by using Kilowatts. One kilowatt = 1,000 watts, so we can say the much greener-sounding "This widget used 56 kilowatts".

Finally, when you pay for electricity, you are paying for your power usage over a given period of time. To make this simple (for billing purposes), the electrical company measures your usage and charges you by the Kilowatt-Hour, or kWh. So, if your widget uses 1 kilowatt and you leave it on for an hour, you just used up 1 kWh.

## Next, some notes about rates, in other words, exactly how much does electricity cost?

This answer to this question is not necessarily simple. Yes, you can easily take your monthly electricity bill and divide the total cost by the total kWh used (which is probably easy to find on your bill). Then, you will get your average cost per kilowatt. Here is an example:

Total bill (\$85.39) divided by total(kWh (468) total = 85.39/468 = \$0.1825 per kWh

Yes, that is indeed a real California electricity bill : If you live pretty much anywhere else, your rate is probably a lot less, even as much as a third less. But then again, you miss out on all the earthquakes. (The rate numbers are updated for 2013).

However, to get a true measure of the cost of a particular device, you should understand its impact on your current usage level. This is because there is not a single rate per kWh. Instead, there are a number of different rates that are added up, and what's more, the more you use, the higher the rates. So if you are using fairly consistent amounts of electricity per month and you ADD ON another device, then the cost for that device will actually be at the highest level you have reached on the rate table. This is what is known as a marginal rate. Since we are dealing here with "toys" that are added on top of the basic stuff like the refrigerator, lights, etc., we will measure cost by the marginal rate. Here is a breakdown of how it works:

There is a "baseline" that is established by the power company. There is a set of different rates for usage up to and beyond the baseline. There is a set of rates for the first 30% above that baseline. There is another set of rates for using 30-100% above the baseline. And there is another set of rates for usage above 100% (or double) baseline. The rates get higher as you go up (Did you expect otherwise??). These rates get complicated to figure out (at least on a California bill) due to the various "delivery-rated charges" and "generation-related charges". But by carefully adding up the rates for each charge for >100% baseline usage, the marginal seems to be somewhere around

\$.30/kWh

The numbers are sure to change as rates fluctuate. For our purposes here we will use a round number of 30 cents per kWh, or \$0.30/kWh, as the marginal cost of electricity. Your situation is sure to be different so get out your electricity bill and start calculating if you are curious. And if you live in California or another place with high rates, you probably understand why this web page is being born. In fact, it appears that the marginal rates for electricity over the last eight years (2005-2013) has DOUBLED. The original calculations for this page were made using 15 cents, now the number is about 30 cents! This makes it all the more critical to be aware of electricity usage and take whatever steps possible to reduce the usage and therefore keep the electric bill from skyrocketing. (UPDATE 2014: I found out that the electricty bills in other states may be organized completely differently than the tiered system in California. The basic principles still apply).

## The Kill-A-Watt

This is the tool that was used for all of these measurements. Its easy enough to find on the Internet, and easy enough to buy for \$20-30 or so. Its also easy to use, despite the fact that some reviewers make it sound complicated. Basically, you can figure out the energy consumption of any device by plugging the Kill-A-Watt into the wall, then plugging in the device to be measured. From the time you do this, the Kill-A-Watt keeps running track of the kilowatt-hours used and the elapsed time. The only trick is to write down the elapsed time and the kilowatts BEFORE unplugging the Kill-A-Watt, because you will lose this information when it is powered off (no problem if this happens, just start another measurement). Leave it on for what you estimate is a time period that will reflect typical usage of the device (because the power consumption will vary depending on what it is doing, this is more pronounced for things such as computers). When you are done, divide the elapsed time by the kWh and you will have the number of kW that device uses per hour. It looks like this:

total kWh divided by elapsed time = kilowatts used per hour

Once you know this, you can use your rate per kWh (That's why we figured that out above) to figure out how much that device costs per hour.

kilowatts used per hour multiplied by rate = cost per hour

Once you know the cost per hour, you can use some multiplications to get a better handle on its cost per month, a convenient measuring stick since the electricity bill comes once per month. Here are some examples:

cost per hour x 8 x 30 = cost per month if left on 8 hours per day

cost per hour x 24 x 30 = cost per month if left on 24 hours per day

All of these can be conveniently and automatically calculated with a spreadsheet. This is how the tables above were made!

## A side note about the "Watts" measurement

When you plug a device into the Kill-A-Watt, one of the buttons will display the instantaneous Watts that the device is using. This is a useful piece of information that can be gathered quickly. I have observed that this Watt reading tends to be about equal to 1,000 times the kWh reading for a device, that is, if the watt reading is at 125 then the kWh is about 0.125. However, because the energy usage will vary depending on a number of factors, it is recommended to use the capabilities of the Kill-A-Watt to measure kWh over a long time period in order to get the most accurate numbers. Nonetheless, this Watt measurement is useful for a quick visual comparison among different devices, so it is included here for your interest.

VAMPIRES

Vampires are devices that consume power even while they are turned off and not being used. They stay in a "standby" mode to allow the convenience of a quick power-up, and/or they display digital clocks. The power that is used by each vampire is small, costing less than 25 cents per month by my measurements so far. The problem is, there can be quite a few of them, and the vampire cost can add up to several dollars per month or more. Not all electronics devices are vampires, for example, as far as I can tell most plasma televisions are not consuming any vampire power. The Kill-A-Watt is the best way to identify the vampires. Plug a device into the Kill-A-Watt and leave it off for at least 24 hours to get a typical measurement. The above chart has all of of the vampires that I have identified. In most cases these are devices that are not used that often, so now they are kept completely off by either unplugging them or switching off power via a power strip.