I chose this so that I can monitor line current draw on a regular basis, then from a portable backup system as needed to manage my backup load.
Update is timely and the readings appear reasonably accurate when compared to a clamp-on ammeter. I trust the kW readings it provides.
I think the software is rather clunky... that is the reason I rated it with 4 stars. On the other hand, the software offers the ability to download the data as a csv file for use in a spreadsheet like Excel. Then, one can graph and analyze the data as needed.
I would recommend this product to others, and have already done so. It's quite handy if you have a so-called "smart-meter" for your line provider: you can compare your billing data with actuals you've taken with this device.
This product has all ready paid for itself. I have right at the front door. If anyone leaves anything on (curling iron, iron, steamer, AC, fan) as we leave the house, I can see it.
I used a kill-a-watt to reduce all the items that suck power. Now I know my baseline when none of the appliances are running. As we walk out the door, if the meter is higher than expected, I send the kids upstairs to find the offending item. It saves money and gives me piece of mind! we use LED lights and they are so low if a few a left on it's hard to tell but they use so little power I can let it go.
Installation took a little planing because I had the power company come out and cut the power (a free service). My power box is very tight so better safe than sorry. Once they showed up the whole thing took 15 minutes. The electric company guy was even impressed.
If I move I'll buy one right away!
I installed the Efergy E2 while setting up a whole-home generator. Now I can see how much electricity I'm using while attached to the utility company, and also see how much of my generator's capacity I'm using during power outages. It's very handy to see how much of my generator's 20KW capacity i'm actually using.
I'm not interested in downloading the data to my computer, so I can't address the software quality. I did notice there is a new version of the software on the Efergy website. The real value of these, in my opinion, comes from going around the house and seeing in real time what effect is produced by turning things on and off. Behavior change is what will save you money. The Efergy is easy to set up, and input your utilities rates. Up to 3 rates and rate periods can be set up.
Hanging on the kitchen wall it constantly nags the loved ones on exactly how much it costs to live. Turn on the hot water, and within seconds it jumps from 15 cents to over $1/hour energy costs. This is great! Really makes sure we are doing the best to conserve energy. The daily average feature is a real eye opener. I told my friends about it and they are considering getting one too. The price of this thing really doesn't make it practical for everyone, but it is pretty reasonable given what it does. Must have for gadget lovers. Be careful on the instal. I clipped my CT's to the main wire in the attic, so no exposed conductors, but the instructions show opening up your loadcenter to clip these on the mains. Turn off the power and make sure it is dead using a meter or voltage sensor before working in there.
This product has already paid for itself!!! In three months we have reduced our electric demand by 1/3 and saved around $100 since I installed this product. It looks like efergy released a new software interface that works much better than the first version I tried. My only complaint is there is no easy way to export the data.
The Efergy E2 Wireless Electricity Monitor is a tremendously useful device, easy to install. Clip the two sensors over the two incoming 240-volt lines feeding your breaker panel, plug the sensors' output lines into the provided transmitter, push the LINK buttons, and the transmitter is wirelessly connected to the portable display unit. The robust wireless link operates at 433.5 MHz and will not suffer interference from cordless phones or WiFi networks.
The display unit is updated every 10 seconds. It shows the instantaneous power in kW, and the average daily energy consumption in kWh for the current, and each of the previous seven days. Other informative historical data are also stored in the device and can be displayed readily. When set to display the instantaneous power, it is useful to walk through the house, display unit in hand, as you turn lights and appliances on and off. It's quite an eye opener. (Five stars so far.)
The company also provides software for Macs and PCs. After reading the literature, and after contacting the vendor, it wasn't at all clear to me how the data get to the computer, but it became obvious once the equipment arrived: there was a USB cable included that plugs into the back of the display unit and into one of the computer's USB ports.
There was no software disc included, instead a link to the company's website was provided. Things now became confusing with the software links buried in advertising. To make a long story short, one claimed Mac link downloaded the PC version, but ultimately, after major fiddling, the proper software was installed successfully. I would recommend that the company appoint an individual to sit beside a newbie as he attempts to follow the installation instructions. This way the major potholes (sink holes) in the instruction manual would become obvious and could be paved over.
The Mac software v2.2 (I can't comment on the PC version) appears to be quite solid and informative and provides a valuable adjunct to the handheld display. It is NOT required if you are happy with the information provided by the display unit.
All in all, I'm very happy with the purchase. The unnecessarily-frustrating software fiddling cost the company one star in my evaluation.