Going Solar Part 4 – I Measure Every 24/7 Electrical Device in the Automated Home

As we mentioned in Part 2, the Automated Home’s base line energy consumption is terrible. There’s no point creating all this energy and then throwing it away.

But which are the most inefficient appliances? In an effort to find out I decided to work my way round the house room by room, measuring each device that’s permanently plugged in and powered on.

I’m not claiming these figures are super accurate. I used an earlier version of this Energenie Power Monitor to take the measurements. Some device’s consumption varied wildly over time, some may reach a deeper sleep level than I measured at while others measured 0.00 where they were clearly consuming at least some power (if relatively little).

With that said, here’s some of the results that I found most interesting.

The Interesting Stuff

Our 8 year old (and still fabulous) Pioneer Plasma is one of the biggest energy guzzlers in the house at nearly a third of a kilowatt when in use. Thankfully thought it has a reasonable (for its age) 0.9 watt standby.

Our Philips Hue White bulbs measure 0.00 when ‘off’ whilst the similar Belkin WeMo bulb showed a 0.7 watt consumption in the same state.

In the study our rarely used HP laser printer topped out at over 700w while in use. It’s standby consumption was hard to measure as it varied a lot, but it’s now unplugged.

The house WiFi was provided by an Apple Airport Extreme that used a constant 9w.

The bedside PortaPow USB chargers measured 0.00 on standby whilst our newer Anker PowerPort 6 idles at nearly 1 watt.

A 32″ LG TV in one of the bedrooms halved it’s consumption (going from around 120w in use to 68w) by setting energy saver to medium. It’s standby consumption is 0.9w.

Two screens on one of the PCs showed how things have moved on recently. An older 19″ LCD monitor consumes more than 2.5 times the power in use of a contemporary and larger 24″ LED panel (18w vs 47w)

Sony’s PS4 costs next to nothing on Standby whilst the PS3 may cost you around a quid a year.

Sky Q

Sonos & Sky Shock

One of the biggest surprises was our Sonos system with some very high standby values. The S5 (Play:5 predecessor) was the highest measuring 8.8w in standby. My readings agree with the official sonos values too meaning our 7 piece system costs almost £40 a year on standby. Ouch.

We love our new Sky Q system (read our review here) but it has a dirty little secret too. It costs almost £60 per year to run the main box plus the 3 minis. I went searching for the official consumption figures for the new Sky boxes and here’s the helpful line from the specs…

Total Energy Consumption in line with Voluntary Industry Agreement for Complex STBs


Scheduled Savings

My son’s bedroom has a lot of kit, including a gaming PC rig with 2 monitors, TV, Sonos etc. We found this system on its own ate 28w with everything in standby. We separated off his network switch and WiFi access point and connected the rest to a SmartThings Power Outlet (£45) and set a schedule where it’s only on a few hours each day now.

This makes economic sense with a payback time of around 2 years on the smart switch. Much less with something like the Energenie Mi|Home module that’s less than £10 and compatible with IFTTT (once you add the Energenie Gateway).

Other items like this 1.8w Ikea LED hall light costs a little over £2 per year to run 24/7 so adding any form of automation would probably not make economic sense.

Good Rule of Thumb


Taking today’s electricity prices (£0.1343 for us currently) then here’s a good rule of thumb to work out a rough annual running costs of a 24/7 device.

Taking its rating in watts and multiply it by 1.2 gives you a rough cost in £’s. For example we measured our Synology 1813+ NAS as using 46 watts…

46 watts x 1.2 = £55 annual running cost

So if the Synology serves us for around 7 years – the time our 2 previous home servers lasted – then this single device will have burnt through almost £400 worth of electricity. Sobering thought.

Low Energy Appliances

There are other devices around the home which we couldn’t measure easily – for example a big rack of X10 dimmers and appliance modules in the loft, various central heating components etc.

It’s something very few of us do, but we should all be looking at power consumption figures for the products we buy, especially fridges and freezers – where you should go for A+ or better. Things have got a lot better in recent times with retailers showing annual running costs for appliances now.

Fridges and Freezers are more difficult to measure because of the stop / start nature of their motors. In a future part of this review series we’ll look at a high-tech energy monitor that can give you most of this information, including for individual appliance, with out all this hard work…

No products found.

Read the full Going Solar Series…

Going Solar Part 1 – Installing a 4kW PV Array at the Automated Home

Going Solar Part 2 – Costs, Incentives & Payback Time

Going Solar Part 3 – I Traded in my Range Rover for a Nissan Leaf

Going Solar Part 4 – I Measure Every 24/7 Electrical Device in the Automated Home

Going Solar Part 5 – Our PV Systems Actual Generation Figures After First Full Year

Going Solar Part 6 – Entire First Years ‘Fuel’ Costs for Nissan Leaf EV – £235

Last update on 2024-04-08 / Affiliate links / Images from Amazon Product Advertising API

4 Comments on "Going Solar Part 4 – I Measure Every 24/7 Electrical Device in the Automated Home"

  1. we have a power strip with inbuilt meter, that we used to check some things (*) – fridges & freezers were of particular interest, because we wondered how well they were performing – ie: they’re built-in, so the airflow over their heat exchangers is not as good as it could be … to get useful readings, we generally measured over several days, even a week … must remember to check our tablets, that we leave on all the time, as HA displays, because there are several & it may add up …

    (*) we have proper pulse meters along with the breakers in our consumer units, and a few elsewhere, too, so for most of the big things we get graphs & tables via the HA system …

  2. Interesting article and findings. Being able to cost effectively and remotely monitor individual applications still seems quite difficult. I was especially interested in the mention of the Energenie Mi|Home and Samsung SmartThings plug. Cheers

  3. I was a beta tester for one of the large utilities. They used a Greenwave system that did a really good job of this. We had sockets to connect most of our appliances single and multi way. We also have whole house meter connections for gas and electricity. It was a very interesting process as like you we found things like an old Tivo that was costing £70 a year and not being watched. It really helped us understand the energy use and what we could or couldn’t change either by behaviour or changing the appliance. Unfortunately they didn’t take it to market, I think it would have just been too expensive. I am still using the greenwave sockets with Fibaro but the energy reporting is no where near as good as Greenwave was.

  4. It’s a good idea to review your electrical consumption. I created a spreadsheet listing the major electrical items in our home and took their consumption from the user manuals. I took an educated guess how long they were in use to give a total weekly consumption by item. This was compared and tweeked to match our overall metered consumption. It was interesting and surprising to see that the compter and freezer were the highest consumers.

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