back to article When geeks turn Green: Performance tune your energy bills

A few years ago I suddenly saw my energy bills as another performance metric that I could tweak just like optimising Lehman Brothers' derivatives calculations that I was nominally paid squillions to do. In fact, this whole area is full of numbers and graphs and science and gadgets and interesting techie puzzles, never mind the …


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  1. Anonymous Coward
    Anonymous Coward

    This is all very interesting

    But what are the up-front costs? Very few of us have £15k+ lying around to spend on solar cells.

    1. Arrrggghh-otron

      R.E This is all very interesting

      I looked at PV, hot water & ground source heat pumps and the PV alone was £14k and was out of the question as I don't have £14k spare.

      Shame the grants are setup the way they are (i.e. FITs - great if you have the capital to take advantage of them but sucks if you don't). It would be far better to offer subsidised installations rather than FITs as more people could take advantage of them (I don't consider the installs where the installation company gets the FITs to be a viable alternative due to ownership issues).

    2. GrumpyJoe

      It's not just solar cells (as it says in the article)

      To be honest, all we did last year was get the cavity wall insulation done and a repairman in to tighten and renew the double-glazing seals - made a HELL of a difference.

      1. Geoff Campbell Silver badge


        Absolutely -- the 80/20 rule applies in spades. 80% of the improvement comes with the first 20% of the expenditure and/or effort. When we first moved into our current place, it was appalling, huge gaps around the doors and windows, no insulation anywhere, 25 year old boiler consuming 1100 litres of oil every two months. A few thousands pounds and a bit of DIY later and the oil consumption was down to 1100 litres a year, and the house felt hugely more comfortable to live in.

        We've carried on making improvements, but as time goes on, each bit of improvement costs more time and money.


  2. Raithmir


    There are companies such as A Shade Greener who will fit solar panels free of charge (if your house is in a suitable location etc. etc.), the caveat being they pocket the money from any surplus electricity generation.

    I did see something on a television program a while ago (one of those Grand Design type ones) where a couple were building a green home. IIRC they said the solar panels were actually pretty poor, and that fitting a small wind turbine made a huge difference. Of course not many people would be able to erect one in their gardens I expect due to planning permissions?

    1. Redbaron

      They also lock you into a 20-year (IIRC) contract, which will make it harder to sell your house if you intend to move during that time.

  3. mikeo

    What happens...

    ...when Damon Hart-Davis and Lewis Page meet in the same room at El Reg HQ?

    1. handle

      Don't you mean...

      ...Damon Hart-Davis and Andrew "resources are invented" Orlowski?

      But I presume teleworking is the order of the day.

      1. Thorsten

        Damon Hart-Davis meeting either Andrew "resources are invented" Orlowski or Lewis "Made-in-USA nuclear technology is a triumph" Page would obviously result in annihilation. If only we could transform the resulting gamma ray photons into electricity...

  4. John Smith 19 Gold badge

    There's always the old school draguht hunting method.

    AKA "The wet finger"

    some of the results of this (especially the *very* high speed air blowing through literally *pinholes* in ceilings) can be quite astonishing.

  5. Anonymous Coward
    Anonymous Coward

    How I reduced MY computer energy consumption

    I don't have any useless crap in my PC, i.e. it's not a blooming christmas tree with pointless knobs, displays, UV lights and LED fans!

    1. Anonymous Coward
      Anonymous Coward


      Now lets not go overboard :-)

      Actually, i think the Computer is probably the single largest consumer of electricity in my house.

  6. Great Bu

    Have you determined if there is any benefit to be gained in overclocking your boiler's ECU ?

  7. Mystic Megabyte

    Free hot water

    This works at 59° north.

    Get three old single panel radiators from a skip. 600x600mm

    Put them in shallow boxes, paint everything black and cover with transparent lids,

    Angle them at ground level outside south facing wall.

    Gravity feed to a second hand indirect hot water cylinder in the house at a higher elevation.

    Lag the pipes and fill with ant-freeze etc.

    Plumb the outlet (top) of your solar cylinder into the inlet of your existing one.

    You now have water at 45° filling your tank in place of cold.

    You boiler has less to do, result.

    1. handle

      Unfortunately... only save less than £100 a year. Very satisfying to do, but a huge amount of work, quite expensive even with second-hand parts, and you get loads of hot water in the summer and hardly any in the winter. If only you could feed it back into the grid. And I'd never buy a second hand hot water cylinder if it would do any harm when it starts to leak.

  8. AndrueC Silver badge
    Thumb Up

    I hope you don't go overboard with sealant. You need some draughts to let fresh air enter and moisture escape :)

    1. handle

      heat recovery unit

      ...if you fancy large-diameter trunking everywhere!

  9. Anonymous Coward
    Anonymous Coward

    Total Cost

    I'd still like to see some analysis on the costs of all of this. When will you get your money back after spending thousands on fancy insulation and monitoring tech?

    You can probably do the analysis based on a few scenarios. For example, one where you live there forever and then recoup your upfront costs over x years, and another scenario where you sell your house and (perhaps) get more for it than you would otherwise.

    I realise this probably isn't your main objective. We got cavity wall insulation done partly because it'll pay itself back in a couple of years but mainly because it's nicer being warmer in winter.

  10. Adam Trickett

    Thermal Imaging

    I borrowed my local borough's thermal imaging camera and surveyed a house a night for a fortnight in my village.

    The people who volunteered for the survey were a self-selecting group so they had done a lot of things already - however in most houses I found something that could be improved - there were leaky doors, windows and loft hatches everywhere.

    It was really good fun and I got to meet lots of non-geeky people.

    Most people can save some money, some people can save shed loads...

  11. Anonymous Coward
    Anonymous Coward


    I choose to know nothing about all these renewables. People get in a panic and install all this stuff like its going to get banned or go up in price.

    The fact is that like everything there will be cheaper and better products in 5 years and better still in 10.

    Everyone doing it now will just have the tat that was rushed to market.

    I predict B&Q will be selling a do it yourself solar panel instellation for £500 in 10 years time.

    Some feeble minds may scoff but just think of all the people thinking there was some sort of everlasting gravy train in installing the internet into peoples houses. Didn't take long for the ISP to just pop a modem/router in the post for free did it.

    The sad fact is once a sizable part of the population are producing their own power the gubbimint will invent a tax or annual licence to make sure they still have money to waste on boll*cks.

    1. chr0m4t1c

      Yes, you're absolutely right, because apart from the cost of the panels the biggest reason why people don't fit them themselves is that they think it's complicated.

      All that stuff about making sure you have a secure mount that won't fall through your roof because it's too heavy and making sure any wiring is up to safety standards (as well as being inspected by a qualified electrician to satisfy legal requirements) is just FUD being spread by the installation companies.

      Or, maybe not.

  12. Anonymous Coward
    Anonymous Coward

    Temperature measurement

    I'm still trying to find a good - not too expensive - wireless temperature monitoring system. I have been toying with arduino/wifi but it just costs too much, even if I run upstairs off one and downstairs from another, with wired temperature probes... Ideally I need to monitor two or three rooms upstairs and three or four downstairs. Real time would be a nice...

    Any ideas? I can currently only monitor my office (where the currentcost meter is).

    1. gaz 7
      Thumb Up

      temperature measurement on the cheap.

      At the risk of banging one and boring others who read the comments to the previous article in this vane...

      I have a Pogoplug (50 quid from Pc-World) hacked to run Debian, and a 60GB usb hard disk I had laid around.

      I have added a linkusbi from and hooked up in 1-wire temperature sensors (DS1820). The sensors are the same as old-skool transistors, and have been fitted into RJ45 plugs.

      These are plugged into Cat5 outlets in each room. These are then patched into a home made "hub" which is connected to the linkusbi. The sensors are free samples from Maxim, but could be bought for a couple of quid a piece. One of the sensors is fitted to the end of a long patch, and strapped to one of the heating pipes.

      The software is HomeAutomation ( which is a webbased opensource app - free of course! The server also has a Telldus tellstick switching cheap remote control sockets from Asda on and off.

      The total outlay for this was about £120, and consumes about 8-10W all told. Temperature readings are realtime.

      The pogoplug also acts as a wakeonlan concierge for my Mythtv server, so that does not need to be on 24/7 now. Also added a second 2TB disk for media via a UPNP server, an ebook network library, and a BT server.

      I also input my meter readings into imeasure, and have dropped my electricity use by about 15% since installing this - That has paid for the kit already! I have also been able to finetune my heating settings saving gas as well.

      The setup is documented on

    2. Tom Reg

      Webcams pointed at $2 thermometers.

      Should work. You can also then see if the cat has enough food.

  13. AdamWill

    Do what

    "A few years ago I suddenly saw my energy bills as another performance metric that I could tweak just like optimising Lehman Brothers' derivatives calculations that I was nominally paid squillions to do."

    So, wait, we're supposed to listen to a former Lehman Brothers analyst's advice on how to spend huge amounts of money?

    Anyone else seeing what's wrong with this picture?

    1. Gordon 10


      Try learning the difference between an investment analyst and someone who worked on their modelling systems.

      1. Anonymous Coward
        Anonymous Coward

        The models that said sub-prime CDOs weren't risky and were correctly priced and hedged?

  14. Anonymous Coward
    Anonymous Coward


    Voltcraft DL-100T USB temperature logger seems about the best option, but still at £30 is a bit steep. I opted for 2 so I can compare indoors and outdoors. Some low cost logging and an interface to the heating control would be welcome...

  15. Anonymous Coward
    Anonymous Coward

    Solar Water Heater

    I love it. It's a bit geeky, I never ever have to remember to turn a boiler on or off, and for than 350 days a year (we live in the tropics) it delivers for more hot water than we could ever use.

    However I don't think, for one couple living in a small house, it will /ever/ pay for itself.

  16. ClassicalD

    Interesting exercise. But economically worth it?

    Asked, but unanswered, was the cost of this stuff. Can the cost ever be recouped by lower energy bills? I doubt it. And if it takes longer to recoup the cost than the serviceable lifespan of the product then it would have been better for the environment not to consume the rare-earths (and facilitate China's mining of them) and the other resources needed for the upgrades.

    "but, it's a net positive", you say? We have this wonderful mechanism called prices that, when they're correct (which, I grant you, is sometimes difficult), help us gauge the resources being used. That's why a recycled can costs more than one made from scratch. The price signal tells you that it takes more resources, uses more energy, burns for fuel, etc. (i.e. is less "green") to recycle than to make one from bauxite.

    1. Gordon 10


      The price argument only works if all costs are properly incorporated into the initial cost - which is very rarely the case.

  17. Anonymous Coward
    Anonymous Coward



    1 - buy warm cardigans suitable for indoor use

    2 - when it feels chilly indoors go outside for a 10 minute walk. You'll be surprised how warm it is when you return indoors.

  18. Tom Reg

    Switching to Heat Pump from Nat Gas will not reduce greenhouse gases

    Electricity in the UK is largely CO2 based - at least all added load is almost 100% fossil fuel based.

    Say your electricity is Nat Gas made. Better than coal, say average for the UK. To make 1000kwh of electricity with nat gas, you need to burn about times that worth of gas. Then that electricity goes down the wire, and feeds into your heat pump, which is lucky if it gets a COP of 3. Which means they burn 3000kwh worth of nat gas to give you the heating ability of 3000 kWh. There are things like line loses, etc to take into account, but reasonably it will not work. You are using the Carnot cycle on both ends - a bit of a Rube Goldberg machine....

    The fact that you have Solar panels on the roof does not play here - any extra power you consume with your heat pump will be created with natural gas or coal.

    Don't get me wrong - I like heat pumps, and heat my house with a ground source one here in Canada, but they generally only make sense when you are away from a nat gas source, which means rural Canada/US, etc.

  19. Leeroy

    Eddie and Richie

    They had the right idea. For those that do not remember the full story. They are stealing gas from next door when the gas man arrives :)

  20. The answer is 42

    Got a car?

    You can cut your bills there too! Pump your tyres up to the "full of passengers" pressure, drive at maximum torque (efficiency) speed, don't use too much gas until the water is 88 degrees (most efficient for heat transfer), look ahead so you never brake and don't wear the tyres out driving over cats eyes. Before you ask, yes, my old man hailed from Scotland. In the home, after boiling the kettle, put the surplus in a Thermos flask and use that as a starter for the next cup.

    Its all very well having a class A house, but you need class A occupants as well!

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