Plug-in Meters Reviewed

Plug-in meters are the easiest of all electric meters to use.  Simply plug the meter into the wall outlet and then plug the appliance to be measured into the meter. The display will show the power used in watts.  Over time, the energy used will be recorded as kilowatt-hours.

Basic plug-in meters may also display min/max voltages, line frequency, current and/or power factor.   Most units allow basic electric bill rates to be programmed so you can see what it costs to run an appliance.

Corded plug-in meters have a faster sampling rate and can be used to measure the higher European voltages using a universal plug.   Some models can record data, others can communicate that data via the Web and have remote on/off capability.

These meters are inexpensive and very useful for measuring small loads.  However, they will not give you a complete picture of your home energy use.  Combined with a whole house metering system they will allow you to build a very accurate inventory of all the electrical loads in your home.  Using our home energy audit, we'll show you how and why this is an important step toward reducing your energy bill.

Basic Plug-in Meter Features

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Model	Kill A Watt P4400	Kill A Watt EZ P4460	Kill A Watt P4480 w/ Graphic Timer	UPM EM 100
Operating Voltage/Hz	115 VAC 60 Hz	115 VAC 60 Hz	120 VAC 60 Hz	120 VAC 60 Hz
Max Load (VA or Watts, Amps)	1875 VA, 15 A	1875 VA, 15 A	1875 VA, 15 A	1800 W, 15 A
Voltage Display	80 V to 125 V	80 V to 125 V	80 V to 125 V	80 V to 130 V
Current Display	0.2 - 15.00 A	0.2 - 15.00 A	0.01 - 15.00 A	0.01 - 15.00 A
Current Resolution	+/- 0.2% Typ.	+/- 0.3% Typ. +/- 1.0% Max	+/- 0.2% Typ.	N/A
Power Display (Watts)	0 - 1875W	0 - 1875 W	0 - 1875W	0 - 1800W
Power Resolution	+/- 0.2% Typ.	+/- 0.5% Typ. +/- 2.0% Max	1 W	N/A
Energy Display (KWh)	0.01 - 9999.9 KWh	0.01 - 9999.9 KWh	0 - 9999.9 KWh	0 - 9999.9 KWh
Energy Resolution	+/- 0.2% Typ.	+/- 0.5% Typ. +/- 2.0% Max	+/- 0.2% Typ.	N/A
Power Factor Display	0.01 - 1.00	0.01 - 1.00	N/A	N/A
Frequency Display	Yes	47 - 63 Hz	N/A	N/A
Cost/ Rate Input	Single $/KWh Flat Rate	Single $/KWh Flat Rate	None	Single $/KWh Flat Rate
Peak Load Identifier	No	No	No	Overload Warning
Time Range	0:00 Min - 9999 Hrs.	0:00 Min - 9999 Hrs.	N/A	N/A
Power Consumption	N/A	10 W max	N/A	N/A
Dimensions (Inches)	5.1 H x 2.4 W x 1.6 D	5.1 H x 2.5 W x 1.5 D	5.1 H x 2.4 x 1.6 D	N/A
Batteries	Not Req'd.	Not Req'd.	3xAAA for Memory	AG-13 or L44 Button Cell (2)
Special Features			7-Day Timer w/ Surge Protector	Overload Warning
Documentation	Brochure Manual	Brochure Manual	Brochure	User Manual
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Corded Plug-in Meters

Moving up a notch in sophistication are the corded plug-in meters manufactured by Watts Up, Inc. in Orem, Utah.  These electric meters are rated for 100 to 250 VAC and 50/60 Hz so they can be used in Europe with their universal outlet option.  USA models are rated for 120 VAC only.

Sampling rates for these units are faster than the basic plug-in meters and they have the ability to record history.  The standard Watts Up model simply measures the load connected to it.  The PRO and ES models can log data and connect to your computer via USB.  The .Net model has Internet connectivity so you can monitor the load remotely and even turn it on and off.

Corded Plug-in Meter Features

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Model	Watts Up?	Watts Up? PRO	Watts Up? PRO ES	Watts Up? .Net
Operating Voltage/Hz	100-277 VAC, 50/60 Hz 120 V,60 Hz USA
Max Load (Amps)	20 A Max, 15 A Cont.
Voltage Display	RMS Voltage
Current Display	RMS Current
Power Display	True Power
VA Display	0 - 2000 VA
Power Factor Display	0.00 - 1.00
Frequency Display	50 or 60Hz +/- 0.1 Hz
Accuracy Range	+/- 1.5% + 3 counts For example 100W load is +/- 1.8 watts
Min/Max Readings	Volts, Amps & Watts No Time Stamp
Cost Display	Single $/KWh Flat Rate
Flexible Interval Setting	No	Yes	Yes	Yes
PC Interface, Software Included	None	USB	USB	Ethernet
Records Stored in Internal Memory	None	>2,000, >30,000 watts only	>8,000, >120.000 watts only	>8,000, >120.000 watts only
USB Interface w/ Logging Capability	No	Yes	Yes	Yes
Remote Power Switching	No	NO	No	Yes
Internet Enabled w/ Web Server	No	No	No	Yes
Internet Subscription	N/A	N/A	N/A	Depends Upon Speed of Data
Dimensions/ Weight	7"H x 4"W x 2"D 1.5 Lbs.
Documentation	Manual  (Applies to all units)
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If you have developed a plug-in meter or know of one that is commercially available in the U.S. which is not listed here, please contact us if you would like to have it evaluated for inclusion on this site.