efergyTrue Power Meter

hard to read in low light conditionsshould be backlit

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 canGonna be tricky to keep track of the ADU usage *unless* the hub can do this. @$120 more!

When we first moved into our house we were having a lot of problems with electricity use. It seemed like no matter what we did our bill was sky high, so I took the plunge and ordered this power meter to see if I could get a handle on things.--INSTALLATION--I'm definitely not an electrician, but if you're comfortable replacing a breaker then installation is a snap. You install two clamps over the mains in your breaker box, and then you wire the sensor into an existing breaker. The only remotely difficult part is wiring the sensor into an existing breaker. You can run the meter without doing that, but the bigger brains in various reviews note that not having it wired into the house electrical supply will give you inconsistent or incorrect results. However, like I said, if you are okay with changing a break it's not that hard. Just make sure you have a wire nut or two on hand. Pairing of the readout unit and the sensor took about 5 seconds.--ACCURACY--I was expecting to see some deviation from my electrical meter, but there is absolutely 0. If my electrical company says I use 30kwh the meter says I used 30kwh. It doesn't get much better than that.--SUMMARY--The unit is extremely responsive, and I have mine updating every ten seconds which has made troubleshooting our electrical usage so much easier. Thanks to the unit I learned that the fluorescent lights in the basement use up 600w when on, my blower uses a whole lot more electricity than I thought, and we found an outdoor halogen that wasn't shutting off properly. While some of the issues we couldn't do anything about, such as electrical usage of the blower for the heater, we have become much more mindful of our energy consumption. I estimate that we're saving close to $30/month thanks to this meter. Obviously your mileage will vary depending on your current habits.

Installation was straight forward everyhting worked great at first. Was looking forward to determining how much our shop and RV was using in electricity until the unit quit working after 3 months.