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54 of 54 people found the following review helpful
5.0 out of 5 stars Delivers in spades.
It has had exactly the effect that it promised: at a glance we can tell whether we have left lights, computers, or even a cooker ring on somewhere unnecessarily, and we go and turn them off. It is cutting our electricity use by at least 25%.What gets measured gets managed. And my husband is addicted: he has even been known to produce it when we have guests, no doubt...
Published on 8 Dec 2007 by O. Turner

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134 of 136 people found the following review helpful
3.0 out of 5 stars Beware - not very sensitive
This meter is great for giving you an overview of your current household usage. It's nice that you can keep the display somewhere central (like the kitchen) and take a look now and then.

However, I kind of got the wrong impression from John Nance's review (21 Jun 2007). This meter isn't really suitable for measuring individual appliances. It's not sensitive...
Published on 20 Jan 2008 by D Easley


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54 of 54 people found the following review helpful
5.0 out of 5 stars Delivers in spades., 8 Dec 2007
It has had exactly the effect that it promised: at a glance we can tell whether we have left lights, computers, or even a cooker ring on somewhere unnecessarily, and we go and turn them off. It is cutting our electricity use by at least 25%.What gets measured gets managed. And my husband is addicted: he has even been known to produce it when we have guests, no doubt boring them to death with his chatter about how much electricity we used to use!
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94 of 95 people found the following review helpful
5.0 out of 5 stars Essential., 4 Jan 2009
By 
Steve (Leeds) - See all my reviews
(TOP 500 REVIEWER)    (VINE VOICE)   
Verified Purchase(What is this?)
This review is from: Owl Cm119 Wireless Electricity Monitor (Accessory)
I agree with everything Paul Ell (above) has written. Like Mr. Ell, I found that the two main cables (apart from the green/yellow earth) from my electricity meter were grey; according to the instruction leaflet one should be red, and the sensor attached to that. I attached the sensor to the right-hand cable, and it was correct. Incidentally it is a very tight fit, a snap-shut fitting which only just fitted the cable; I assume the designers intend this.

In general, I think the booklet could be improved upon; it is in very small print and did not seem particularly easy to understand at first reading, although there is also a fold-out 'idiot's guide' included with the box. Also you MUST have a really small cross-headed screwdriver to hand (like a jeweller's) to get access to the battery compartments on both sender and receiver units. (Batteries are included thankfully).

Having said all this, once up and running, I have found it invaluable. You can set the display for Cost, Energy (kW) or Greenhouse Gasses. There is a problem with the Cost function, as if like me you are on a tariff which decreases once past a certain kWh useage, the Owl cannot be set to automatically adjust, although it can be set to adjust to different tariffs at different times of day. So I have mainly used - as I suspect most people will - the Energy display. This shows how much energy is being consumed at any one time and is a real eye opener. I found that a 3 bar electric fire which had all the bars turned off was still using approximately 700 Watts! This turned out to be a convection heater which is built in and which I had, until now, assumed to consume negligible current. Also, like another reviewer, I found that despite turning off/ unplugging everything in the house, there was still over 100 Watt consumption taking place. Is that the meter itself.....?!

Seriously, it really is worth every penny, and I am sure will rapidly repay its cost given today's energy prices.

Recommended strongly.
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134 of 136 people found the following review helpful
3.0 out of 5 stars Beware - not very sensitive, 20 Jan 2008
This meter is great for giving you an overview of your current household usage. It's nice that you can keep the display somewhere central (like the kitchen) and take a look now and then.

However, I kind of got the wrong impression from John Nance's review (21 Jun 2007). This meter isn't really suitable for measuring individual appliances. It's not sensitive enough to accurately measure many things. 60W devices register, but not accurately (e.g. switch one 60W light bulb on - the reading goes up by 30W; switch a second identical 60W light bulb on - the reading goes up by another 80W). Low power devices such as TVs, Hi-Fi's and radios don't register at all. If it's small appliances like these you're interested in measuring, consider one of the plug-in meters.
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17 of 17 people found the following review helpful
4.0 out of 5 stars Interesting Gadget, 25 Oct 2008
Other reviewers have stated how easy this thing is to set up and in the main it is, apart from the sender unit which has tiny screws in the back of it and in order to insert the batteries you have to fiddle for ages with them to get them out. You also need a very small screwdriver in order to remove them, which not everyone will own. Other than that it was simple to attach to the incoming power cable and set up the unit. It instantly showed how much electricity my PC is using and I calculated that by turning off my PC when not using it we will save approximately 27 on our electricity bill. As we have 2 computers in the house this will be a significant saving, as our last bill was 200.

I agree with other reviewers that it would be helpful to have historical data but for 30+ it a useful gadget for showing just how much certain items consume and with electricity prices rising all the time it is certainly worth knowing what items to turn off when they are not in use in order to save money :)
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139 of 145 people found the following review helpful
5.0 out of 5 stars Don't buy this toy!, 20 Jun 2007
By 
John Nance (UK) - See all my reviews
(REAL NAME)   
Excellent and curiously engaging toy.

It arrived the next day and was up and running within 5 minutes.

Do not buy this toy - otherwise you'll find yourself running round the house turning everything on and off. My only topic of conversation now is the relative power consumption in standby of the toaster and PC.

Setup was straightforward. You just clip the meter around your electricity cable, and tell the monitor to search for the meter. Was up and working in just a few minutes.

The handheld monitor works all over the house so you can see exactly how much electricity you're using - and work out what's using it.

In some ways it's not really necessary. We all know to turn off our TVs at night and that halogen lights are expensive to run. The difference is seeing the impact of every device. It really drives it home.

In my case, it's going to save me 30 a month because I know the equipment that's driving up my electricity bill.

Buy one!
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76 of 79 people found the following review helpful
2.0 out of 5 stars Seriously Flawed though it has its uses, 19 Aug 2010
Verified Purchase(What is this?)
This review is from: Owl Cm119 Wireless Electricity Monitor (Accessory)
Despite reading in Watts and Watt-hours and claiming to measure power consumption and energy, this unit actually measures only V-A (Volt-amps). In fact it really only measures amps, which is all it can do without an actual connection to the mains, and then multiplies by the assumed voltage. This leads to HUGE ERRORS because certain appliances draw current out of phase with the voltage, giving rise to vastly inflated readings. The ratio of actual Watts to V-A for an appliance is given as the 'Power Factor', and for most fridges and freezers and other devices with induction motors it is around 0.3, so don't be surprised when your 50 watt fridge reads 160 watts. It gets worse: some electronic devices like induction hobs draw considerable capacitive current when they are switched OFF; probably because they incorporate large capacitors to filter the high-frequency noise they generate and stop it getting back into the mains. My two-hob induction unit reads around 100 Watts on the Owl even when turned off, though it is not actually consuming power, just pumping current in and out of the grid ninety degrees out of phase with the voltage! The true facts were revealed when I connected this and other devices through one of those little plug-in power monitors which do read true power as well as current and power-factor.

The 'base-level' power in many homes is taken by fridge and freezer, plus a few things on standbye, and in my case reads around 350 Watts even though it's actually nearer 100 Watts - very misleading as this is a major contributor to total energy used because it is on all day! At higher readings, when cookers and kettles are used, the readings are fairly accurate, as such devices have a power-factor of one. Interestingly, the added contribution of fridge and freezer is then also correct, because the high resistive loads swamp the out-of-phase current producing an overall power factor very close to one, which is what counts.

Even more confusing is the fact that turning on my induction hob at the wall (but leaving it turned off) REDUCES the reading on the Owl considerably! This is because it draws capacitive (leading phase) current which cancels some of the inductive (lagging phase) current drawn by the fridge and freezer. Add to this the resolution limitation and it's all rather useless, though I actually find it useful to monitor my total load on my solar off-grid system so that I can keep within the 3kW limit of the inverter. Sorry to get a bit technical, but I think this is necessary in order to give some insight into the mysteries reported by other reviewers. If the manufacturers did it right, and didn't make such false claims, there would be no need for all this - they should bring out an alternative clip-on unit which also plugs into a socket, measuring true power by muliplying instantaneous current and voltage, and needing no battery. The monitor itself could remain the same.
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14 of 14 people found the following review helpful
5.0 out of 5 stars Spend to save, 15 Jan 2008
By 
Mr. Michael D. Hunt (UK) - See all my reviews
(REAL NAME)   
Fantastic Product.

Is it accurate to the enth degree ? I'm not sure but it does focus your attention and clearly indicates along the lines of consumption. It becomes a family game of trying to keep the conumption below a certain value. Once settled, you can tell at a glance that somebody has left the iron or amersion on upsatirs which in itself is worth the cost. Educational for kids ( and adults ), beneficial to the planet and in the long run.....your wallet.

Simple to install ( takes 30 seconds max ) and a very useful tool. You'll just be wary of that 3KW fast boil kettle from now on........

Brilliant !
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50 of 53 people found the following review helpful
3.0 out of 5 stars Useful, but not superior to plug-in meter, 22 Jan 2008
By 
Alan Clarke (UK) - See all my reviews
(REAL NAME)   
One reviewer assumes that this item is more accurate than a plug-in power meter. It isn't - the plug in meter measures both voltage and current, giving an accurate power reading, whereas the Owl just measures current, and not very accurately it seems, either.

Only gives consumption figure at the time, and multiplies up to an annual figure, which of course shoots up when you put the kettle on. Better models store historic data which is more useful.
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30 of 32 people found the following review helpful
3.0 out of 5 stars Not what it claims to be, but use it as ..., 24 July 2008
By 
Kaio (UK) - See all my reviews
(TOP 500 REVIEWER)   
Verified Purchase(What is this?)
Like any other gadget in the "energy usage monitoring" category, you should not really rely on the measurements displayed. There are numerous factors that make the reading inaccurate. That said, you can use it to spot if there are appliances left switched on; say, if you switched off all major appliances and get a substantial wattage reading than normal, may be you forgot your PC on, or you left on that WC light downstairs. My advice is, use it for simple diagnostic/monitoring and not for precision, and don't get carried away to save the planet with this gadget as the readings can not be relied upon!

Should it be as expensive as that? May be not. The good news is that over the recent weeks prices are coming down by at least 30% (for instance, discounted by Argos to comparable prices here on Amazon).

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Review Update - 21 April 2009
Since my initial review in July 2008 it appears that an enhanced version of this product has been introduced that incorporates features such as date/time and memory of historical data which I highlighted as missing features. It means that the following paragraph may not apply to the revised product. I will update the rating/review once I get hold of the new version of this gadget with date/time and usage data memory features.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With regard to one feature, I am a bit disappointed by the fact that the Owl model doesn't have a time display which would have made it more functional, say in the bed room where you can check that last reading (as well as time check which would be handy). Which leads to "congratulate" the Efergy model which has a clock, but cannot comment further as I haven't seen it in operation. From what I have read, the Efergy model also memorises usage data to work out averages which is a more meaningful data (again as a trend indicator rather than accurate data). The Owl model doesn't have the memory feature. The Owl model worked without any problem such as picking up the sensor signal from quite a distance, but as for the reading there is more to do with the whole physics and nothing to do with this simple sensor gadget. I hope the manufacturers are honest to be upfront with this and say that the readings cannot be accurate as simple sensors cannot provide accurate power readings (due to inductive load or power factor issues, inaccurate current sensing, voltage variation, et cetera).
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7 of 7 people found the following review helpful
4.0 out of 5 stars Watch and see the cost, 30 Nov 2010
By 
C. Tipping (Scotland) - See all my reviews
(REAL NAME)   
This review is from: Owl Cm119 Wireless Electricity Monitor (Accessory)
Have had this gizmo for about a month now and am still fascinated by it. It was comparatively easy to fit - we had to fit it in the 'cupboard' outside the house but it was straightforward. We didn't have any problems with battery fitting but we've got enough tools to start an ironmongers. You just need a small screwdriver - probably available in the pound shop if you haven't got one so won't break the bank. The display is clear though the decimal point isn't always obvious from across the room so don't get misled from a distance! Setting it up takes a little while and there are options for tariffs that don't necessarily apply to your case. We just keep the display on 'cost per hour' and watch as it jumps from less than 2p to over 20p as we switch some greedy appliance on. Nice to see how little all our energy-saving lighting costs though.

So far, we haven't been shocked by the cost of different appliances - we knew the oven, the washing maching, the kettle, the dishwasher, the iron, etc., used electricity like Niagara uses water BUT we didn't SEE it as it happened. It makes a difference when the money vanishes before your eyes. This hasn't made us give up washing, cooking, making tea, etc., but it has made us think carefully about making the most of everything. It's too early to tell if our electricity usage will fall noticably in the next year - there are other variables like visitors, friends for meals, etc., but it has certainly helped us to concentrate on what we do rather than once a quarter when the electric bill comes in.

Well worth having if you want to know what's going on. Just don't buy one if you'd rather stay in the dark. Or stay in the dark all the time and save even more money....
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