Energy Savings

Revision as of 20:02, 9 October 2008

How much money will Vera save me on my energy bill?

Naturally this depends on many factors, including how much your local utility charges you for electricity. So, we'll present a hypothetical example here based on a family in California with a 3 bedroom home, with prices as of October, 2008.

Without getting too technical, the amount of electricity you are using at any given moment is measured in watts. Lights are the most common ways to use electricity, and how many watts the light uses are printed on the light bulb. 100 watts is typical. How much energy you use over time is measured in Kilowatt hours (Kwh). This is what the electric company charges you for. There are 720 hours in a 30 day month, so a 100 watt light, if left on all month, will use 72 Kwh. In California, like in most places, each home is allowed to use a very modest amount at a low price, and as you use more, the price goes up. Currently the cheapest price is 11 cents per Kwh, the highest is 35 cents. So leaving a 100 watt light on all month will cost you $7.92 for the month if your overall energy usage is very low, and will cost you $25.20 for the month if your energy usage is higher.

When you save energy, reducing your overall usage, you are saving money at the highest rate. So look at your utility bill and see what the highest rate you are paying is. Here is the usage for our California home with a $233 electric bill:

1,291 Kwh used for the month
Baseline Usage 317.20000 Kwh @ $0.11559
101-130% of Baseline 95.16000 Kwh @ $0.13142
131-200% of Baseline 222.04000 Kwh @ $0.22580
201-300% of Baseline 317.20000 Kwh @ $0.31304
Over 300% of Baseline 96.77500 Kwh @ $0.35876
Total $233.31

So, in this case, keeping that 100 watt light off will save $25.20 per month. We are only allowed to use 317 Kwh of electricity at the base rate before our rate goes up, this means 440 watts continuously. So if we had only five 100 watt lights on over the month we'd be using more than our base rate and paying the premium rate. Here are some common items and how much electricity they use: