Price: $130 (plus ?? for Wi-Fi).
There's something about the Envi that makes it a dud, in our eyes. While it may have certain uses, for most people there are better options. The Envi provides a rather clumsy display unit. It is cluttered with lots of different measurements, several of which cycle between one reading and another. All of the readings are in the same font and size, including the readings for kW and $, and none of these are bold or large. The display also includes time, and the temperature, as well as various displays of readings from the past few days and month, all of which just add clutter and provide only marginally useful data, at the expense of readability. The display is low-contrast and hard to read, with no back light. The display has no batteries so must be near a plug, which seems like a silly idea, to me. It has no wall mount.
Unlike the Blue Line monitor, the Envi requires an attachment in your electrical box. This sounds frightening, and probably will scare off 90% of potential buyers, but in truth, there's no actual electrical connection to be made -- there are just two special clips that wrap around the main power leads to measure current flow. The clips are small and well-designed to make the job a moment's work. The leads from these clips plug into a sending unit, which comes with a bunch of pre-installed batteries which they claim will last for 7 years. The Envi can support standard 2-phase services in most US single-family homes, or 3-phase services found in multi-unit housing and some commercial buildings (with a 3rd clamp, not included). The sending unit makes a wireless connection with the display, and has reasonably good range.
The readings from the Envi are approximate, since to calculate watts (or kW), you need to know current (which it gets from the clips installed in the box) and voltage, which you program as 120V or whatever your service provides. The problem is that voltage fluctuates during the day; compared to other meters, the Envi was reading significantly higher in my testing -- my voltage fluctuates between 119v and 126v, which is apparently enough to throw off the reading (for example, an actual reading of 402W (0.402kW) was displayed at 0.46kW, which is more than 10% high. Nevertheless, the overall trend is close enough for most people.
The Envi has a USB port and comes with a wire to connect to your computer where you can access the stored data in various forms. Several third-party software applications are available; only one would work on my Mac, and its readings didn't agree with those of the Envi itself (which as noted before were wrong). I tried some of the Windows software, and it varied between overly complex, to just bad. I didn't find any software that I would have actually used on a regular basis, especially with a long wire running from the display to my computer.
The makers of the Envi claim that they have a network interface in the works (a $70 option, available in August, with Google PowerMeter support), and that might indeed make the Envi data more easily accessible. We'll keep an eye on the price of the WiFi/Google interface, as this could change things a little.
Comments
We have found the Current Cost monitor to be quite intuitive and informative with its data downloads and other features.
But you are right - it is not 100% accurate because it measures current and assumes voltage (unlike your powercost monitor - reading the rotating disk on the meter - which looks great!). This is our review of the accuracy of the current cost monitor. And our full write-up on the new EnviR energy monitor.
Posted by Ryan on Dec 6, 2010 10:16pmThanks Ryan. Unfortunately in this (and a few other things relating to energy) the US is lagging behind Australia, where your store is located; the version we have to sell in the US is not as pretty.
I don't think accuracy is that critical for most cases, especially when used only as a tabletop display. My house tends to run at about 3% to 5% above rated voltage until usage ramps up -- meaning the Envi reads a little low. But another factor I didn't mention in my review is Power Factor (PF) -- loads that use alternating current motors, especially large one like air conditioner compressors, can appear to use less power than they actually do -- we saw one particular compressor whose PF was less than .5, meaning the current reading and resulting apparent power calculation was 1/2 of actual.
This kind of discrepancy is far from common, but when you start getting to a level of detail, which is more likely as you start tracking power usage over time these levels of detail can become important. For example, if you had a low PF compressor running in the summer, you might be surprised to see how things changed as the weather cooled in winter (well, at least here in the northern hemisphere :-).
In any case, our conclusion was simply: here in the US, there are better options for most cases than the Envi.
Tom
Posted by Tom Harrison on Dec 7, 2010 9:32amHi. Thanks for the review. I actually have purchased the Current Cost Envi model and most of your comments are spot on. I did not know of the possible fluctuations of the wattage reading due to not having a voltage sensor but for me I guess it's not a big deal if it's off a few watts here and there (I'm not a pro, I just want to know if there are items in my house using electricity when they shouldn't be).
I did have to attach the Envi receiver to my always-on laptop in the living room (which also acts as my voip landline) via a USB port so that did kind of limit where I could place it but it works out for me too.
Btw, I have placed most of my experiences and tips about the installing and using the Envi on my site at http://www.energynovice.com. Hope this helps out others in making their decisions.
Posted by Gerald on Feb 15, 2011 4:43pm