Efergy True Power Meter - Measures Voltage and Phase for Higher Accuracy No Wi-Fi Required.

This device is well constructed, easy to install, and does exactly what it says it will do. If you're looking for an energy monitor that compensates for power factor to give you the most accurate reading, this product is the best choice right now. Unlike most other energy monitors, this product includes an AC/AC adapter that powers the transmitter and let's it track your line voltage for better accuracy. The adapter is molded on one end to insert directly into a knockout in your main breaker panel (see photo). One wire coming from the adapter can be ganged onto an existing breaker and a second wire goes into an open slot on the neutral bar. The package also includes a bushing for a second knockout for the current sensor wires to exit the main panel. Overall, it's a straightforward installation and the product includes everything you need. I have both this and the OWL CM119A. As far as construction and ease of installation, I'd say both are similar. The Efergy TPM requires extra work to install the power transformer, but in exchange you get more accurate readings and don't have to replace transmitter batteries. As another commenter mentioned, the current sensor lead wires are short, but they're about the same length for both devices. I'm using both the Efergy and the Owl with a home-grown monitoring system on a Raspberry Pi computer with a usb rtl-sdr dongle. People have posted code for decoding RF transmissions for both the Owl and the Efergy. The Efergy uses a more sophisticated FSK modulation with a 16 bit CRC, while the Owl uses an Oregon Scientific v3 compatible Manchester encoding. The Efergy protocol is probably more robust, but it requires some extra code compared to the Owl and may be a bit more cpu intensive on the Pi (my app uses 20% cpu decoding these two sensors along with 6 other temp/humidity sensors). The Efergy transmits at 10-20 second intervals, while the Owl transmissions are variable from 6 to 60 seconds depending on whether the current is changing. Google efergy decode or owl decode for example decode routines. My code is posted on github under rtl-wx.

Installation was pretty easy, clamp here, clamp there, and pigtail a breaker. I'm monitoring an ADU to see the power usage thru a sub panel. I still had to mount this in the house main panel as there just wasn't enough room to put the components into the smaller (8 panel) unit. I've pretty much figured out how to program the tariffs, 1,2,3,4 are times/sections and 5 is weekend. Here in the US *my* tariff is 16:00 - 21:00 M-F Peak and 21:01 - 15:59 off peak (2 different price tiers 7 Days a week). The weekend is the same hours, and this device only has one weekend price tier. So Saturday/Sunday it's .15¢ from 21:01 - 15:59 and .41¢ from 16:00 - 21:00 but no way to tell/program this device to adjust for this. It's either .15¢ all weekend or .41¢ So I'll have to look at the device (weekends), starting at 16:00 and mental calculate 16:00-21:00 and adjust accordingly. I'll have to see if the History can Gonna be tricky to keep track of the ADU usage *unless* the hub can do this. @$120 more!

This is a psychological pavlovian device and a great way to get the kids / wife (or husband) and friends (though you may have fewer when your done) straightened up and using significantly less power in your home. And if you weren't really watching your energy usage before it will pay for itself in a couple of billing cycles especially if you live in one of those fun were going to charge you anywhere from $0.16 to $0.38 cents kw/h states (remember its not just the base tariff you have to add in all the fee's, taxes. surcharges, and extra charges for green power). I researched multiple models including the OWL,TED even the open source version and broke down the costs, the functionality for the basic single family home this is the hands down the best functionality (it isn't everything, but the next step up is way more expensive) for the price. The important thing about this model vs. the other efergy models is that that will actually measure the phase angle, oh heck with it.. fine its 3% more accurate than the other models. Plus you don't have to worry about opening up the breaker panel every couple of months or whatever and changing the batteries in the transmitter. Here's the thing - if you really want this to be useful you need to get the Efergy Hub as well and for some bizarre reason this seller does not offer the Efergy TPM with the HUB as a kit on Amazon but does on other to remain unnamed but rather famous sites. But here is the link for the hub http://www.amazon.com/dp/B00AXYY5UY YOU WILL HATE THIS IF YOU DONT GET THE HUB. GET THE HUB. How does it work - well you know those horror movies... where that creepy doll or shadowy figure keeps showing up in the corner of your eye, tempting you to acknowledge it. That's how it starts. Soon you will start carrying it around like its your newborn and then its like that the other horror movie, you know the one with Jack Nicholson - The Shining.. next thing you know your wife and children are flinching when you come around the corner carrying your trusty true power meter saying things like "turn that off if you aren't using it". And then threats come - "if you don't turn that off I am putting that on a timer".. and then you do. How did it work... Did you ever see your power bill go down... during the winter... in Alaska? 12/12/2014 DAYS # 28 KW/H 518 TOTAL $ 88.62 11/14/2014 DAYS # 31 KW/H 719 TOTAL $ 119.82 10/14/2014 DAYS # 29 KW/h 876 TOTAL $ 144.20 12/13/2013 DAYS # 29 KW/h 968 TOTAL $ 141.25 It wasn't like I just plugged this device in and boom my power bill went down - but it helps you shape your and your families behavior and gets you do the "little" things that make a difference. And even my wife will admit that she didn't really notice any lifestyle changes due to the power saving changes we made and now is even more conscientious of power usage than she has ever been and even catches me now and then.

hard to read in low light conditions should be backlit