Measurement Validates Conservation

Issue #103, July 2010
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Table of Contents

Measurement Validates Conservation

The Value of Monitoring Systems

Monitoring on a Budget

Ten Energy Saving Tips

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Measurement Validates Conservation
Physicist Lord Kelvin, who is credited with developing the Kelvin temperature scale that starts at absolute zero, made famous the quote "If you can not measure it, you can not improve it." Adapting this philosophy into the finite energy world in which we live, Home Energy's slogan is "Measurement Validates Conservation."

Our focus is to draw attention to both measurement and conservation. If no effort is made to conserve then all net measurements are zero and there is no need for a monitoring system. Nothing changes, nothing improves. If focus is purely on conservation without measurement, then there is no way to empirically determine if an energy saving idea is a good one or a bad one.

As the heat of summer roles in we are reminded of the importance of conservation as the electrical grid strains to meet the cooling demand. Adding permanent generation capacity takes years and is very expensive. Utilities will eventually have to make this investment, but is us, the consumer, that will pay for their return on that investment through higher rates. If new generation expense can be postponed, so can the rate increases that will accompany it.

Political attempts to curb energy use through such legislation as Cap and Trade will prove to be nothing more than an indulgence tax on carbon production which is passed onto the consumer. Utilities may shift load to green energy sources, however, outside of hydro, the amount of power they contribute to the overall grid is minuscule. True conservation would have a greater impact at this point in time. Electrical energy will continue to be produced in quantity by fossil fuels for years into the future.

Impact on the environment is another important consideration. Regardless of which side of the global warming debate you are on, there are measurable changes in the size of certain glaciers and the arctic ice sheet for example. Whether these changes are natural or man made remains open to question. If time proves they are man made, any energy conserved at this point in time will contribute to slowing the climate change process as well as make our air a little cleaner to breathe.

As discussed in last month's Meter Messenger, the Smart Grid is emerging. Standards are being developed at a vigorous pace to define how products and services will communicate and control energy information. Energy pricing will be driven by this information. It will favor to those who comply with conservation practices and penalize those who do not. Measurement is key to understanding your energy consumption pattern and level of usage so you can adapt smoothly to these future changes.

Renewed emphasis on energy conservation will continue through energy pricing initiatives and attempts at government legislation which will further increase energy pricing. Smart grid technology will play an increasing role in how energy is monitored, delivered and priced. Energy measurement gives you a good tool to prepare for these changes by revealing what energy conservation practices will be most cost effective in your home or business.

The Value of Monitoring Systems
What, really, is the goal of good measurement? I think most people realize that when accurate information is presented in greater detail a more precise level of understanding can be achieved. They also realize that more information means more data to digest and more time will be required to do so. This paradox sets one of the primary ground rules of a good measurement system: simplify complexity without diluting accuracy. In other words, provide a tool which can boil down volumes of data into digestible pieces of key information that one can use to make better decisions.

The closer energy monitoring systems come to achieving this goal, the more value each has. Lets look at some examples. At the lower end of the spectrum is the data logger. It simply records a raw data parameter such as temperature, humidity, amps or volts on a fixed time interval.

Extracting valuable information from this data requires one to download it to a comma separated value (.csv) file, synchronize time lines and perform mathematical analysis. As a result one can determine relative humidity from temperature and humidity data or power from amps, volts and power factor. The information is available but requires time and effort to extract.

The next level encompasses devices that measure at a single point and provide some level of internal analysis on the data being collected. For example, a plug-in meter measures volts, amps and power factor to determine peak power and provide an accumulation of kilowatt hours and cost. A simple energy meter reader that records usage from the utility meter and time stamps peak power usage is another example. However, the ability to store logged data and download it for further analysis is generally limited with these devices.

The third level includes home energy monitoring systems that have the ability to record and analyze data at more than one measurement point. These systems interface with a computer via USB or Ethernet and have sophisticated graphical user interfaces that boil down large volumes of data into simple, easy to understand graphs and charts. Multi-point measurement provides usage information for large appliances and/or additional panels. Some monitors even have enough inputs to monitor at the circuit level.

At the highest level are three-phase, revenue grade power quality meters that are used in commercial and industrial applications. These meters can be networked and have the ability to upload extensive amounts of data into large databases for analysis in real time. Software can aggregate input from a building, a campus or different locations across the globe. The information can be viewed and analyzed by multiple users simultaneously.

As measurement value increases, so does cost. Plug-in meters are inexpensive starting at $30 to $50. Simple data loggers start in the $50 to $100 range. Home energy monitors start in the $150 to $250 range. High-end commercial and industrial monitors and associated software run in the thousands and tens of thousands of dollars for full installations and are beyond the scope of Home Energy

As a good place to start, we recommend keeping the price of your first energy monitoring system at or below twice that of your monthly electric bill. That way, at a modest 8% to 10% savings rate you will recover your investment within two years. As you grow more familiar with the benefits of monitoring, you may wish to invest in additional equipment.

Monitoring on a Budget Last month we featured a new energy monitor called the eMonitor that can monitor power consumption at the circuit level. Although this is a great tool, you'll need a fairly high electric bill ($400+/month) to financially justify it. This month, we will take a look at the lower cost portion of the metering spectrum.

The lowest cost metering device is the Kill-A-Watt P4400 plug-in meter. In its bare bones configuration it runs about $30. If you are willing to spend some time, this device can provide a reasonable estimate of the power used by most all of your 120 volt appliances. Simply plug your appliance into the meter and read what amount of power it draws. If you leave it plugged in for several hours or a day, energy usage can be determined.

Use our FREE Power Panel Profiler MS Excel workbook to record the different readings you take on each circuit. The Profiler will roll up loads from each plug or light switch into overall power and energy readings for the entire main panel. The only thing you won't be able to capture with the plug-in meter are the 240 volt loads such as the air conditioner, electric hot water tank or the clothes dryer.

Capturing these loads can be done with an energy meter reader such as the Energy Owl, Blueline Inovations or Black and Decker power monitor or an entry level home energy monitor such as the TED 1000 or the Efergy Elite. If using an energy meter reader, net metering techniques will need to be deployed to determine 240 volt loads because they only gather data from the utility's electric meter. These units are moderately priced in the $90 to $120 range.

Since the entry level home energy monitors use CT's to capture current information, they can be used to measure the actual load for the 240 volt appliance via sub-metering. Simply clip the CT's on the wires leaving the breakers serving those circuits. Each appliance will need to be measured separately as there are only 2 CT's, one for each 120 volt leg. Although whole house measurement will need to be suspended during this process, you will be able to get accurate power consumption data for the appliance being measured.

Record voltage and current readings for each leg of the 240 volt appliance in the Power Panel Profiler to determine power. Daily run time on air conditioners or hot water tanks can be determined by dividing the kilowatt-hours measured in a 24-hour period by the amount of power the device draws in kilowatts. Be sure to convert wattage readings to kilowatts by dividing with 1000.

Entry level home energy monitors are priced in the $150 to $175 range. Coupled with a simple plug-in meter you can make an accurate assessment of how power is used in your home for about $150 using a meter reader or $200 with the basic energy monitor option. As you make changes to your usage pattern or add energy saving devices you can make new measurements, compare them with the original baseline and determine your savings.

More advanced home energy monitors provide great graphics across computer networks and can measure at more than one location at a time. However, they cannot, by themselves, provide the level of detail you can achieve by measuring each circuit and tracking it in the Power Panel Profiler. Going through the process of itemizing each electrical load in your home will show you where the best energy saving nuggets reside.

Ten Energy Saving Tips
1. Be sure that lamps or TV sets are not running in the vicinity of the thermostat. The heat they emit can affect thermostat temperature and cause cooling equipment to run longer than necessary.

2. Clean the lint screen on your clothes dryer before every load. Lint build-up slows air circulation. Reduced air circulation means more run time for the dryer.

3. Replace 75 or 100 watt recessed incandescent bulbs with 50 watt halogen bulbs. Efficacy ratings (lumens per watt) are much higher for halogens then incandescents to you get more light with less energy. This works well especially in kitchens and bathrooms where good lighting is important.

4. Programmable thermostats control the biggest energy user in the home - the heating and cooling system. They are one of the best energy saving tools in which to invest and start in the $50 to $100 price range. Click here to visit our latest suggestions on selecting and using programmable thermostats.

5. Try to avoid running large heat generating appliances such as the range or clothes dryer during the middle of the day so they do not compete with the air conditioner. Use these appliances in the morning or evening when outdoor heat loads are less.

6. Use bath fans and range hood fans prudently. They can expel a whole house of conditioned air in an hour of inadvertent operation.

7. Use a toaster oven or electric fry pan when preparing small meals to avoid turning on the oven or burners on the range.

8. When cooking on the range, be sure to use properly sized lids on the pans. The covered pan will bring contents to temperature more quickly and use less energy to cook the food than one left uncovered. Stove top clean-up is easier, as well.

9. Thermostat set points cost money. For every degree you lower your thermostat below 78 degrees, cooling costs go up 3 to 5 percent. The same is true in winter for heating costs above 68 degrees.

10. Electric hot water heating is one of the largest, single sources of energy use in most homes. It is second only heating and cooling. Click here to see lots of great ideas about how to lower hot water energy costs.

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