Interesting. That's a dead ringer for the 2000MU-UK sold by Maplin under the catalogue number L61AQ and is in fact the Euro version of the famous Kill-A-Watt meter sold in North America.
You can check out its specs at the Maplin site but it's worth noting that the consumption figure is actually VA (20 in this case, otherwise
10 for the American version). The actual power used is just under half a watt. The very low PF is simply down to the use of a simple voltage dropping capacitor to provide the 5 to 10v DC required to power the electronics and display.
Whilst you're on maplin's website, take a swift look at the N67FU. This is only £9.99 and is just as good, assuming you're not overloading the socket with anything that'll be drawing more than 13A max.
Both meters have equally good accuracy, agreeing within a percent or three of my trusty Metrawatt analogue wattmeter.
In fact, having had a look at mine, that is exactly what it is.
The manufacturers name is Prodigit Electronics, but there is also a small Maplin WEEE sticker on the back. But as in the Amazon link, I've seen it sold under other brand names (and none).
Bought from Ebay though as it was cheaper, because a I knew it was a version of the Kill-a-watt and that had a good reputation.
I'm not actually sure where the actual display bit of the monitor is right now - it got put in box during a sort out and rearrange of things here.. But I log it all on a computer.
Mine is only about 15w, I turn everything off at the mains when not in use e.g. internet router, computer, TV, etc. About 10W of it seems to be due to the combi boiler which I think has an inefficient transformer, since it's permanently warm to the touch even with the central heating off.
My average consumption with things turned on is about 200W, most of which I reckon is a pretty even split between lights, fridge, and computer or tv.
When I bought mine, I didn't realise that it was a thinly disguised "Kill-A-Watt", only, like the other three digital wattmeters I purchased from "Maplin Man"[1] in our local flea market, that they were digital wattmeters more worthy of the name than that pathetic DEM1739 I'd previously bought from Aldi a few years earlier and, more to the point, were only 3 or 4 quid each with a money back guarantee. :-)
One of the other 3 wattmeters had failed after about a year's use monitoring the NAS plus UPS consumption, the remaining two being those N67FUs I mentioned which are still going strong two or three years on.
It was only after scrutinising the instruction leaflet in the L61AQ box that I realised it was a 2000MU-UK which suspiciously had its power consumption listed as 20VAmax which the idiots in charge of Maplin's website had translated into watts (I'd already confirmed the consumption was a more reasonable 1/2 watt or so)[2].
[1] So called because the vast majority of the electronic gadgets he was selling had been the result of him winning a bid on a job lot of Maplins returns at some trade/bankrupt stock auction somewhere 'down south'.
He did have some interesting items in amongst the usual USB tat which was why I was drawn to his stall like a moth to a flame(effect neon lamp) - I never got burned. You just never knew what goodies would be laid out on his stall from one week to the next.
I was able to purchase several universal laptop charging bricks, often for less than 8 or 9 quid each and I soon learnt to recognise which ones where the 'lemons' that had either already blown up or were inevitably going to do so[3].
I never had any problems returning such 'lemons' for a refund or exchange. It soon became apparent that he was selling them untested which is fine when, as he did, the seller is quite willing to offer an exchange or refund without argument.
I soon discovered that a lot of such returns to Maplin were the result of their customer 'trying it on' or availing themselves of the
7/14/28 day satisfaction or money back guarantee so were as good as brand new, damaged or no packaging aside. Other stuff had been deservedly returned due to (usually stupid design faults) making them fail or behave unreliably.
Two classic examples of this come to mind. The first being the mis-use of the small 4 pin power connector normally used on 3.5 inch floppies on a universal USB to IDE/SATA adapter module which caused no end of trouble with full size IDE or SATA drives. Since there wasn't any real need to disconnect the short molex/sata power flylead (it was too much bother trying to unplug it anyway), I simply unsoldered the male connector and chopped the plug of the flylead and soldered it directly to the PCB - problem well and truly laid to rest!
The other example related to a USB only SATA docking station where I had to cut the 5v circuit trace on the mini USB socket to stop troublesome backfeeding the 5v rail of any sata laptop drives with insufficient power. Since the docking station had its own seperate
12/5v power brick, needed to power the larger 3 1/2 inch drives, I can't understand the sloppy thinking by the designer of the PCB used other than he/she must have been a victim of the 'consumer age' so infecting the education system - "schoolboy howler" indeed!
[2] It wasn't till I googled for more information about the Kill-A-Watt that I realised its link to the 2000MU-UK meter. The similar confusion over VA (10 in this case - 120v mains versus 230v mains) and real watts being the final clincher.
[3] Unless the charging brick is blessed (or cursed) with its own cooling fan, a no load consumption above 2 watts is untenable in a sealed plastic box (and some of them would show a no load power draw of 3 watts or so - if these had been actual returns, it was a bloody miracle they hadn't already blown the internal safety fuse in a big way.
The routine of post purchase testing involved both output voltage testing _and_ no load power consumption measurements. The ones supplied by the laptop manufacturer rarely showed a no load consumption greater than half a watt, often being more like a quarter or one third of a watt.
A jeweler's loupe allowed me to interpolate the two watt scale markings on my trusty Metrawatt to such low values with complete confidence in their veracity - it's only my experience with those two maplin digital wattmeters that allows me to now do such critical testing using those particular meters.
Experience with cheap "wattmeters" purchased from Aldi and Machine Mart a few years earlier had given me plenty of cause to strongly doubt the accuracy of digital wattmeters at such low power levels when being used for such critical testing.
Taking the DEM1379 meter as an example, it was quite capable of showing anywhere from zero to 15 watt readings on an smpsu powered item drawing 5 real watts so you can see where my initial mistrust came from. If you are looking for a cheap digital wattmeter, make sure it isn't old stock of those earlier meters being offloaded.
They'll give reasonably accurate readings on resistive loads greater than 100 watts which might be enough to convince the typical punter of their efficacy as an energy consumption monitoring device but are completely uselsss when it comes to measuring the consumption of the more interesting mains powered electronic gadgets (even including desktop PCs drawing in excess of 100 watt).
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