Here in the UK smart meters have been available from the big six power utility providers for some years. I’ve refused the free installation service as the first generation smart meters could not be ported if you changed providers. This changed with the rollout of the 2nd generation meters and so we’ve now had the system installed for gas and electricity consumption monitoring.

What’s consuming 300 watts?

Several years ago I bought a cheap electric power monitor from Maplin, another casualty of the high-street, that indicated the house standby power was around 300w. That’s 300w of essentially wasted electricity. The Maplin device sends a new reading every 30 seconds and the monitor has a similar latency so it can take a minute or two to see the difference between unplugging one item and another. So it’s time consuming looking for differences to identify where the power is going. I hooked up the monitor to a Raspberry pi and wrote a little Python program to log the power in the hope of processing the data at some point. Of course, I never got around to it and ended up puzzled as to where the 300w was going.

Click on a few years with the new smart meter installed it’s confirmed the power consumption with everything switched ‘off’ is still around 280 watts. So what is consuming this power – is it the smart meter? After switching off each circuit at the fuse box I found the culprits are on the house ring (95w), garage (140w) and upstairs lighting circuits (31w). The kitchen ring has around 13w standby probably due to a number of remote control sockets and the power meter’s supply!

It’s surprising how all this standby power adds up and how tech is mostly to blame. The ring has the BT broadband hub which drinks about 15w and arguably is actually doing something rather than just idle. There are also six 1Gb/s ethernet switches that take about 60w plus a wifi and smart lighting hub another 15w with the remainder remote control sockets. The ethernet is used for TV streaming of Netflix, Prime and BBC iPlayer – wifi can’t support the bandwidth reliably – but the 1GB switches remain on continuously when not being used, 60w day and night.

An old poorly chosen fridge in the garage is the likely 140w guzzler plus the outdoor motion sensor lighting that’s permanently on standby drinking a few watts each.

Device Standby power
Remote control sockets (x12) 24W
Samsung TV 10W
Network Switches (x6) 60W
Security lights (x5) 25W
Kyocera printer 5W
Total standby power 124Watts

Nag nag nag

One of the benefits of having a smart meter continuously displaying your home’s power consumption is the visibility it brings. 3.3Kw making a cup of tea, 1.6Kw defrosting some bread in the microwave, 1.2Kw as the underfloor heating comes on in the den. 2.65 Kw when the dishwasher kicks in. These power spikes from the quiescent become familiar and awareness of the cost of running home appliances makes you think.

Smart meter displaying 2.68 KW showing weekly budget exceeded

Smart meter 2.68KW Weekly Budget Exceeded

You can choose various combinations of dashboard information on the smart meter. A combined view shows the total cost per day of gas and electricity with traffic light colours for low medium and high consumption.

Or you can focus on just electricity or just gas. Gas is not a concern as off means off. Our old Potterton gas boiler, that will soon be replaced, does not have a wasteful pilot light that is always on waiting for action. It’s the electricity that’s tricky. Perhaps I should not complain. Replacing the old tungsten lighting with compact florescent and now LED has made a huge difference over the years. Our kitchen originally used five 60w reflector bulbs along with six 20w halogens for under cabinet lighting which consumed 420 watts. That reduced to around 160w with LED with over twice the lux.

UK Standby Power Costs £4bn?

After a few months of watching  the nagging smart meter and consciously switching off devices that we don’t use much to avoid the standby consumption the lowest reading showed 180w. It does not sound much but that’s around 60p per day or £220 per year. With 27.6m households in the UK assuming let’s say 150w standby power on average (a wild guess given we have a few more tech gadgets than most) and that’s costing the UK over £4bn in wasted power consumption. Yes 4 billion pounds and quite a lot of CO2.