Issue #111
March 2011

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Table of Contents

Envi Power Monitor - An Economical Option

Goal Setting - The Key to Real Energy Savings

Is Solar Power a Viable Option for Your Home?

Ten Energy Saving Tips

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Envi Power Monitor - An Economical Option

We have just added the details for the the Envi Power Monitor to the Smart Meters page at Home Energy Metering.com. The product is manufactured by the UK based company, Current Cost, and distributed by Power Save, Inc. in the US. Its sales have been strong in Europe but has just recently entered the North American market.

The Envi power monitor offers a low cost alternative to monitoring energy consumption in the home. The device uses a transmitter located at the main service panel that sends a wireless signal to a remote display. The display shows power, energy and cost readings along with time and temperature. This basic package is self contained and does not require a computer to operate.

However, with the addition of a USB cable the Envi Power Monitor can be connected to any PC. Third party software developers have created a variety of different dashboards that can be used to view and analyze the electrical data. Some are free, others are very reasonably priced. So, for about $150 you can install a whole house energy monitoring system which you can log data and monitor usage on your computer.

This is the starting point. The system can be expanded to monitor up to nine additional devices and can be set up to communicate over the Web. The display can accept and log input from one to ten different transmitters. Each transmitter can read single phase (120 volt), double (240 volt) or three phase (208 volt) based on the number of CT's connected to it. It is possible to measure 480 volt three-phase power but readings must be multiplied by 2.3 to compensate. A future version will handle this automatically.

If you want to measure the larger electrical loads in your home, simply add a transmitter and CT's for each appliance you want to measure. The display has a channel selector that allows you to look at each load individually but it does not aggregate. If you want to aggregate or net loads, for example, when measuring solar PV or wind generation, check the third party software details carefully to be sure that the features you seek are provided.

Additional measurement points do come at a cost. A transmitter with one CT for a single phase measurement retails for $59, 2 CT's at $79 and 3 CT's $99. As you can see, a mult1- measurement point system can add up quickly. A good rule of thumb to remember is to keep the cost of your energy monitor system below twice that of your monthly average electric bill. This way, by saving a conservative 8-10% you will pay for the system within two years.

An option to using the USB cable to communicate with your computer is to add a web bridge which is offered for $69. This device allows you to connect the display to your router. Electrical data can be uploaded to your computer via Ethernet and/or sent to Google Power monitor which allows it to be viewed from any portal to the Web including mobile phones and electronic tablets.

One of the reasons the Envi power monitor has an attractive basic system price is that it does not measure voltage. The voltage level is preset at 120, 240 or 208 depending upon the CT configuration. In addition to low cost, this approach increases safely because no connections to live wiring need to be made. CT's are simply clamped around the primary conductors and the monitor displays readings.

The drawback to this approach is a reduction in accuracy and there is no monitoring of voltage levels to assess power quality. The Envi power monitor accuracy level holds a +/- 5% variance which the company claims is closer to +/- 1% when voltage levels remain close to nominal values. This is usually acceptable for most residential applications but accuracy will remain below that of the utility's meter.

In conclusion, the Envi power monitor is a good entry level device to measure kilowatt-hours and provide feedback of instantaneous power usage. The rate feature simple assigns a cost per kilowatt-hour which is OK for flat rates. If your rates are tiered or time-of-use cost estimating will be less accurate. Also be aware that third party software applications may not always run as smoothly as one would like and are not supported directly by the equipment manufacturer. The low entry price makes this energy monitor attractive - just be sure you understand and accept its limitations before purchasing.



Goal Setting - The Key to Real Energy Savings

"You cannot improve what you do not measure" is our mantra at Home Energy Metering.com. Measurement provides the information to define a base line from which any type of change, good or bad, can be measured. However, measurement in and of itself does not reduce energy costs - it only provides information that, if acted upon in an intelligent manner, can reduce energy costs.

The false assumption that many home energy monitor customers make is that their electric bills will drop by simply installing an energy monitor. This is not how it works. Action must be taken on the information the home energy monitor provides to reduce energy cost. This action may require the additional expense of replacing incandescent lights with compact fluorescents or LED's. Habits may need to change such as using a toaster oven or microwave in lieu of a regular oven or sweeping rather than vacuuming.

The trap that many fall into, is once the novelty of a new gadget fades with the distractions of day to day life, so does the attention to those energy saving habits one tries to instill. A key strategy to avoid this trap is to have written goals on how much energy you are planning to save. Use this goal as a target to strive for as you continue to look for way to reduce energy usage in your home.

An energy services company, Cape Light Compact, of Barnstable, MA is taking this concept one step further by developing behavioral-modification software. In a recent study of 91 participants, the average daily electrical consumption fell by 9 percent. The test was set up to measure participant energy usage with a whole house energy monitor that fed a personalized and secure web page. The site also provided interaction with other participants and offered energy saving tips geared toward conservation.

At the start of the program each participant was asked to state a goal of how much electrical consumption they wanted to reduce in the coming year. The average goal of all participants was 14 percent. The people who set the highest goals achieved the most energy savings.

The web site used a point system visible to all participants - nothing like a little friendly competition to boost motivation. Individuals would set daily usage goals and were awarded points based upon how well they performed. Points had value as they could be redeemed for gift certificates of which some participants used to purchase energy saving devices.

Goals are a key ingredient to a successful energy cost reduction program. They need to be aggressive, yet realistic. We offer a FREE tool for developing and tracking those goals called the Power Panel Profiler. It is a comprehensive spreadsheet that analyzes all of the circuits in a standard 200 amp, 40 circuit electrical panel. In addition to tracking your energy measurements you can use it to to set your energy reduction goals by circuit. Overall savings rolls up through the calculations giving you a more accurate energy reduction goal to strive for.



Is Solar Power a Viable Option for Your Home?

As we start to move into warmer weather with longer days and more sunshine the question of installing a solar photovoltaic system (PV) system often comes up. The idea of powering our homes purely from the energy of the sun is one we all relish from time to time - but how practical is it - really? Well, it depends...

It depends on your weather in terms of average hours of sunshine per day. It depends upon your cost per kilowatt-hour from your utility and any incentives they may offer for solar installations. It depends upon how much power you use to power your home and how much of that load you want to carry with solar. It depends upon how much you can afford to spend on a solar project and how you plan to pay for it. It depends upon the size system you really need to reach your alternative energy goals.

These are all factors a solar system installation contractor can evaluate for you if you are serious about starting a project. But what if you are not there yet? What if you just want to get a general idea of what type of system you will need and how much it will cost and what kind of payback can you expect?

We found a great tool that you may find very useful in evaluating the practicality of a solar PV system for your home. Go to our Home Solar Energy page and click on the link to visit BP's Solar Economic Estimator. Enter your zip code and indicate whether you are interested in a residential or commercial solar PV system.

Based on your zip code the Estimator knows your city and electrical utility and rate schedule(s) that apply. You enter the size of your bill and the rate at which you expect it to escalate. Select the size of the solar system you want to look into and the estimated installed cost per watt. Financing options include a home equity loan, a non-deductible loan or paying cash.

Once these parameters have been entered the Estimator returns a system cost and shows which Federal and State tax credits apply and how much they would save. A variety financial options show first year net cost, annual cash flow and what effect the system would have on your monthly electric bill. Monthly and daily solar PV output in kilowatt-hours shows how much you can expect to produce with the solar system and how much power you will continue to purchase from the utility.

Inputs are very easy to change and show immediate feedback in dollars and kilowatt-hours. This estimator is particularly useful because it takes into account the top three factors used to determine the financial practicality of a solar PV system:

1. Your geographic location which determines the daily average number of hours of sunshine you can expect each month.

2. The amount you pay for electricity from your utility and how much that cost can be offset by solar generated kilowatt-hours.

3. Various incentives available to you at the state and federal level.

Check it out! I think you will find it quite interesting.



Ten Energy Saving Tips

1. Keep track of your energy bills on a spread sheet that shows both cost and consumption. Include gas if you use it. Graph the spread sheet and post it where everyone in your family can see it.

2. If you do not yet have an energy monitor you can still get a good idea of your energy consumption by recording readings from your utility's electric meter each day. As an added feature track your outside air temperature or check on line weather stats for your area. Since heating and cooling typically comprise at least 50% of your energy consumption you'll most likely find a strong correlation between temperature extremes and high energy use.

3. Unplug battery chargers when not in use to reduce vampire loads. This includes any type of charger - cell phone, cordless drill or laptop when not in use. The coils in the chargers continue to draw a small amount of power, even when nothing is connected to them.

4. Plug power supplies for computer peripherals such as speakers or game boxes into a power strip and shut them completely off when not in use. Better yet use a smart strip that has master and slave plugs. Plug your computer into the master and when you shut it off, everything plugged into the slave outlets shuts off as well.

5. Not sure about what temperature settings to use in your programmable thermostat. For heating try awake at 69 F., away at 62 F., home at 70 F. and sleep at 67 F. Heat pumps with auxiliary heat strips may require smaller setbacks when away to minimize heat strip activation. For cooling try awake at 76 F., away at 84 F., home at 78 F. and sleep at 75 F.

6. As we move from cooler to warmer weather check your house for air leaks around doors and windows. Put that caulking gun to work around windows and add weather stripping where it has deteriorated around exterior doors.

7. Have an attic? Is the access door insulated? If not, build a small frame to clear the spring assembly and wrap it with a hot water tank insulation jacket. Another option is to build a box out rigid foam insulation and place it over the attic door.

8. Here's a simple test to find air leaks in your home. On a windy day hold a lit incense stick or smoke pen next to windows, doors, outlets, recessed lighting fixtures, plumbing pipes or any other location where outside air leaks may occur. The smoke pattern will indicate any air leaks that need attention.

9. If you have a fireplace be sure to close the damper for the warmer months ahead.

10. Its a good idea to have your air conditioning system checked and services by a qualified HVAC contractor at the beginning of the cooling season. A minute refrigerant leak can waste a lot of energy before you realize there is a cooling capacity problem in the mid-summer heat.


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