Energy Savings

Latest revision as of 03:36, 14 April 2010

[edit] 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 at any given time. 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.

The amount of electricity consumed by any device is measured in watts. Light bulbs, the most common electrical device in most homes, have a wattage printed on them, with 100 watts being typical. The total cumulative electricity used over time is measured in kilowatt hours (kWh). This is what the electric company measures and 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 of electricity.

In California, as with most regions, each home is allowed to use a very modest amount at a low price, while the price for electricity increases as you use more. In our example, we'll assume the cheapest price for electricity is 11 cents per kWh, and the highest rate is 35 cents. So leaving a 100 watt light on all month would cost $7.92 if your overall energy usage is very low, and $25.20 if your overall energy usage is substantially higher.

Here is a breakdown of an electric bill for our example family's California home:

Electricity usage for the month of October, 2008: 1,048 kWh
        (Note the increasing kWh cost for each pricing tier)
        0-100% of Baseline = 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 bill $233.31

For this family, reducing energy usage by 23%, to 809 kWh, would reduce their bill by 1/3, to $153, because any energy savings come off the highest rate. Look at your utility bill to find the highest electricity rate you are paying. In this case, keeping that 100 watt light off would save the family $25.20 per month.

Note that the utility company in this example has set the "baseline usage" at 317 kWh of electricity, which translates to 440 watts used over the course of a month. That means if this family left five 100-watt lights burning all month, they'd use more than their baseline and begin paying premium rates for any electricity usage beyond 317 kilowatt-hours.

Here are some common household items and how much electricity they use, along with what it would cost per month, at the premium rate, if they were left on all the time. (Of course, the air conditioning unit would likely not be running 24/7, even if it was left on, because once it got the house to the set temperature it shuts itself automatically.)

So, how much energy can Vera really save me? Let's add up some common savings:

In this example, we only looked at three simple ways Vera can reduce energy usage, and for the California family described here using 1,048 kWh in electricity, and paying $233/month, Vera would save around $90/month, well over 1/3. If you were considering a software-based home control system that runs on a PC, note that leaving the PC computer on all month can cost between $20 and $90 per month in electricity if you're already in the premium rate category, and will use up a lot of the energy you saved. Vera uses only $1.50 of electricity a month and does the same thing, a fraction of that used by even the most power-efficient laptops.