Efergy e2 USB Wireless Energy Monitor

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Feature Packed

This is the latest wireless energy monitor from Efergy, the e2. It represents a big leap forward for the Efergy brand and offers features only found previously on much more expensive monitors. The Efergy e2 is smaller and more compact than its sibling, the Elite, although the display has larger digits for the main values, making it easier to read from a distance. As with the Elite, the e2 carries forward every single positive aspect of the original model, with significant improvements in many areas including vastly improved transmission range. The Efergy's strongest point has always been its superior memory function. The e2 has the same memory capability with easy access to figures on energy use by day, week, month, and year on the display unit itself.

USB Connection

The big news story on this new model from Efergy has to be the little USB connector on the back. The Efergy e2 stores up to 8 months worth of hourly data in its own internal memory which can be quickly downloaded to a PC for more detailed analysis using the supplied eLink software and cable. The eLink software will enable you to develop a greater understanding of how electricity is being used within your home through graphs showing usage patterns, costs and carbon data.

Economy 7

All monitors in the Efergy range now provide compatibility with Economy 7 supplies. The e2 features a multiple tariff facility which allows you to set a different rate per kWh for up to four individual time periods. Please note that as with all wireless energy monitors currently offering Economy 7 compatibility, this feature is suitable for use with 'white meter' supplies but not the older style dual circuit installations where two rates are charged simultaneously overnight and it may be necessary to purchase additional sensors.

The e2 transmitter runs on a set of three AA cell batteries (not supplied) which according to the manufacturer should lead to significantly improved battery life. The display unit requires three AAA cell batteries. We advise the use of either Lithium batteries for extended service life or Hybrid re-chargeable batteries, both of which reduce the impact of waste on the environment.

Our verdict

The Efergy e2 is brimming with features and technology, making it an absolute Geek's delight. We like the no-nonsense styling of the e2 and it feels solid to hold. The little LED which flashes each time data is updated is a nice touch. We know that many people have been waiting for a cost-effective wireless energy monitor with a USB connection and it's finally arrived in the e2.

	Price	Delivery	Total	Buy Now
Maplin Electronics	£39.99	FREE	£39.99	VISIT SITE
Amazon	£43.99	£0.95	£44.94	VISIT SITE
Evengreener	£50.00	£5.00	£55.00	VISIT SITE
Nigel's Eco Store	£49.11	£10.74	£59.85	VISIT SITE

User Reviews...

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Average rating of 3 from 2 users.

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Dave Hogg

Methlick

24/07/2011

Use with wind turbine

Just as with PV panels I soon found that when connected at the meter the device measures current in both directions and records consumption and production. I obtained a second device, the first is located on the turbine side of the connection and mea

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R Prendergast

Hemel Hempstead

04/02/2011

Beware if you have Solar PV!

Prior to buying the energy monitor, I had solar PV installed at my house. Today, I noticed e2 monitor was showing consumption running at some 2 kW at a time when hardly any electricity could have been being utilised in the house. What I did observe,

was that (since it was a rare fine day) my solar PV system was generating and indicating that power was being exported. I have to assume that the e2 monitor was actually monitoring this net export of electricity, rather than net consumption. I imagine that the e2’s sensor (fitted to the feed cable) is not capable of distinguishing the difference.

While this may not cause a major problem in terms of instant readings (I can make a mental adjustment), it will tend to make a nonsense of energy consumption data over time.

I emailed efergy with this information, and added: "As you are in the business of energy efficiency, I am sure you must be aware of this problem. I cannot find, however, anything in your installation instructions (or your website) which offers a way round this problem. With the rapid growth of solar PV generation in the UK, in response to the new FIT regime, many of your customers are surely going to run into the same problem – especially if, like me, they are sufficiently energy-conscious to install solar PV and one of your monitoring systems.

Is there any way round this problem? Fitting the monitor to another cable (upstream from the solar PV feed)?"

The reply I got was as follows - make of it what you will:
"We have mixed results when installed within solar installations as it was designed to work on standard home electricity supplies where the loads of the home used energy directly from the grid. If the feed live cables are used for both export and import of electricity then for us to determine totals our readings will be inaccurate.

The monitors work by a sensor attached to the live feed and are measuring the current flowing through the cable in one direction, it cannot compensate for flow in the opposite direction, in fact will read it again as consumption even if it is not.

If installed beyond the inversion and the current is drawn only by the home resistive loads then it should show energy consumption in the same way as a standard home type. As we are reading in Kva and only transposing with the use of a mimicked supply voltage to show as Watts then we assume the power factor to be = 1 always. This may not be the case in your photovoltaic circuits and as I am not an electrician/installation engineer the power factor could differ and also reactive power be generated, which our monitor cannot compensate for and may display, incorrectly, any reactive power in Va as a small wattage of use. I am not sure of a conclusive solution in your case but if you use the services of a qualified electrical/installation engineer he may be able to recommend a position in the circuit or even the use of a second monitor to help you get accurate information with respect to your export and imported supply."

Note from Electricity-Monitor.com: The DIY Kyoto Wattson is currently the only domestic wireless electricity monitor capable of monitoring micro-generated power in addition to power consumed from the grid. Whilst the reply from Efergy here is quite technical in nature, it confirms that the e2 was not designed to be compatible with homes feeding micro-generated power back to the grid. Thoughtful positioning of the sensor may allow the monitor to detect only the power consumed, although this would still include self-generated power when available.

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