2022-08-28

Saving energy...

There are a lot of "tips" for saving money on energy now.

A lot are downright insulting... Some are stupid - there is a lot of myth on "standby power" of modern devices which is just wrong, or at best, out of date.

To be honest, my main tip is simple - understanding what you use. If you can understand what costs the money you can decide if and what to reduce. People have a really poor perception on what costs and what does not, and people will spent a lot of wasted effort saving 10p when some other measure could save £10.

To get it right you have to get a grasp on what costs and how much.

And, much as I hate to say it, a smart meter with an in home display, is a start. They are pushed on us all for misleading reasons. They don't, on their own, in any way, "save money", and they contain a contactor, or "cut off", that can be remotely triggered, which is kept surprisingly quiet. But if you have one, and set up with a display, you can see how much you are using "right now" on gas, and electricity.

If you don't have one, you can ask for one. If you don't have a in-home display, ask for one. Ask your energy supplier.

The other thing is reading the ratings on things and doing the maths. Now, I know some people seem to struggle with this. A calculator may be your friend if you are not sure, but it helps to get your head around some of the things. I appreciate this is a massively "dumbing down" blog post, and not like me, but I can only hope it helps.

For most people the gas side is simple enough, a cooker, and gas central heating, maybe. The smart meter can show how much you are using. See what you use cooking a meal, for example. That is usually not too hard. You can use the meter to see how much, for example, lowering the thermostat 1C can make. But remember the weather varies day to day too. And also, the smart meters are not as quickly updated for gas, it seems.

But for electricity, people have so many more devices all contributing their little bit to the costs, some a lot and some a little. They all add up. An electric oven is a lot. Electric heating is a lot. Anything that "pumps", even water pump for my heating, uses noticeable electricity. And of course, things like a tumble drier, washing machine, hot tub, or an electrically heated floor, or an electric car, are seriously a lot. Heating and pumping are the big power users.

Time and power

Cheap power monitor
The two things that matter here is how much power something uses (measured in Watts, or W for short), and for how long it uses the power. Electricity "units" are a kWh, that is 1,000 Watts for one hour, and each unit costs, from October, something like 57p.

  • Use something for longer, and it costs more.
  • Use something more powerful, and it costs more.
  • Use lots and lots of small power things all the time, that adds up.
So, don't be put off by the smart meter showing usage in "red" or some such because it is a lot right now (like a kettle). What matters is the power and the time. There are things that are not that bad because they are short. There are things that are not bad because they are very low power, even if on all the time.

A kettle, for example, may say it is rated at 3kW, meaning 3000W (which is a lot), but you use it for maybe 3 minutes. That means 0.15kWh (3/60 times 3), so 8½p worth. Boiling less water reduces the time, and is a simple saving you can make. It is only pence, but it is a saving.

I have talked of kW and W, and you need to understand the scale. "k" here means "kilo" which is 1,000. But you may see things using mW, where "m" means "milli" or 1/1000th. Read the label carefully. The units are kWh, meaning 1,000 Watts for one whole hour. This is the same as 2,000 Watts for ½ hour, or 500W for 2 hours.

One small tip, with lighting, they often have "equivalent power", e.g. something may claim to be equivalent 100W. Once upon a time (and I am old enough to remember) we had actual 100W incandescent light bulbs. A 100W bulb, on all the time, would cost £1.37 a day, crazy. These days such bulbs may actually use only 10W and be LED based, so 1/10 of the cost. Some are way less. Even so, keeping lights off when not needed can add up - a few pence here and there.

That said, some lighting is more expensive than you realise - maybe lots of "halogen" downlighter fitted some years ago. The key here is - use the in home display - try one thing at a time - find what power it is using.

Also, the "energy efficiency rating" you see on things, like "A rated", are not really helpful. They are more "how good is this thing compared to industry standard". Some things have higher standards than others. The real thing to look at is the power usage and time used. Yes, if you can replace something with a new thing that is more efficient, great, but what matters is how much less power the new thing uses, not what letter it has.

Of course some things are a tad deceptive, a washing machine is moving and heating and pumping (all of which are bad), but for various periods and not all of the time. So checking its "power rating" is not that helpful as that is the most it can use at any one moment. A trick there is run it and see how much the in home display on the smart meter says you have used while running it (allowing of how much is used for the same time without doing so).

But if you see how much, for example, a tumble drier uses, and have the option to line dry things instead, you can see what you save.

If you are really not sure, you can literally turn everything off, and run one thing, to see what the display says it has used, or what rate it uses, for just that one thing.

But some things are low enough not to worry about. For example, a TV on standby is likely to be around 1½W. That is not kW, but W, so if a TV is on 24 hours that is 24 x 1½ which is 36Wh, which is 0.036kWh, which at 0.036 units, and at 57p per unit is 2p, for a whole day on standby. I mean, yes, it is a saving to unplug it, but just boiling half as much water in the kettle saves more.

  • So try and do the maths to work out what costs what. Decide then what you can reduce.
  • Use the smart meter display, try turning things off / on and seeing how it changes.

Of course there are longer term, and more expensive, measures we can all take, like improving insulation, and upgrading heating systems, adding energy monitoring stuff, solar panels, and batteries and so on, but to be honest, if you can afford that you probably are not the target of this blog post.

Energy is heat

Bearing in mind, any power saving in lights, TV on standby, broadband router, or anything else, using electricity, in the house, ultimately means more power used to heat your house. All of the used, or wasted, power in the house is 100% efficient heating of your house. That is where the energy goes. That does not help in summer, but it does in winter. If using gas to heat your house, less of a problem, as it is so much cheaper than electricity to heat. But if using electricity to heat your house - any saving on lights, TV, even kettle, are ultimately increases in power used to "heat". All your used electrical power ends up as heat. This means all those apparent small savings for an electrically heated house are a total waste of time - the real saving is putting up with a few degrees colder, sorry.

Similarly for gas - e.g. we have gas central heating, and a gas oven and hob in the main kitchen/living room. When we use gas to cook, in the winter, the gas used to cook will heat the room and so save on gas used to, err, heat the room. Of course, the cooking needs venting somewhere too, so again, not so simple.

Whenever we think of energy used or wasted, and saving it, think about where that energy goes.

(OK, a few exceptions, my tumble drier pumps warm air out of a vent and the washing machine flushes hot water down the drain, and it is a matter of where in the house the heat is, but in most cases the electrical appliances in your house end up heating your house 100% efficiently)

No help

Let's be clear, all of these tips, even mine, will be fuck all help to a lot of people where the cost increase just to stay alive is way more than they can afford. Sorry. All I can say is please make sure you vote when you can - to make the country better somehow.

22 comments:

  1. One thing a lot of homes suffer from is if they have halogen (note this is absolutely not the same as LED which is what would normally be fitted today) downlights installed. Back in the day it was done often as an 'energy saving' measure as a halogen lamp is more efficient than a traditional incandescent one, however if you go from one 60 or 100W light to say five 50W halogen downlights, you're suddenly using around 2.5 times the power :(

    I remember one property a friend was viewing as they were considering buying that I went along with them to, and every room had been done like this - I pointed out that on a typical evening if they had their living room, hallway and kitchen lit, they'd be burning nearly 2kW on lighting, which was mad!

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    1. Excellent point, and using the in-home display, turn everything off, and turn on one thing to see what it uses, will massively help people work out if they have that. Thankfully changing a few light bulbs / fittings is not that expensive.

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  2. Move to Abergavenny and tap into the geezer with the Starlink dish

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  3. Smart meters also have the ability to limit the total power drawn at any given time ('Load Limiting'). Surprise, surprise, this hasn't been publicised !

    You could soon find that at peak times it's a case of 'Smart Meter Says NO': you can use the kettle OR the oven OR the hob OR the washing machine OR the tumble dryer, but not two or three simultaneously.

    Of course, Load Limiting restrictions will apply only apply to the 'little people', not to MPs, ministers, their chums and their cronies.

    Surge pricing is also on the way for those with smart meters, but most so-called 'journalists' are so gullible that they've just unthinkingly copied and pasted the press release which claims that people will be actually PAID if they shift consumption away from peak times !

    Well, the glove's velvet is so soft and attractive...

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    Replies
    1. Cite your sources for the load limiting. And how would it work? Cuts off your supply entirely if you use more?

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    2. All is revealed in Smart Metering Equipment Technical Specifications 2 (SMETS2), e.g. see the sections starting at Lines 1346 (Load Limiting), 1501 (Surge Pricing), 4902 (Electricity Kill Switch) and 5065 (Gas Shut-Off Valve).
      smartenergycodecompany.co.uk/download/29586

      Also see
      www.esi-africa.com/industry-sectors/energy-efficiency/load-limiting-a-smart-solution-to-reduce-the-need-for-load-shedding/

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    3. No, there is no load limiting. What the spec states is that a threshold can be set and various actions can be taken if this is exceeded, such as logging, alerting or even cutting the supply. There is no capability for the meter to limit the supply. Every domestic supply already has a limit in the form of a fuse, and the local network capacity.

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    4. > "No, there is no load limiting."
      That's clearly nonsense, the specified facility wouldn't be called 'Load Limiting' if it didn't do precisely that. You've even contradicted yourself by (correctly) saying that the supply can be cut if the threshold is exceeded. What is that, if not Load Limiting?

      In addition to the 3% and 6% voltage reductions, if the supply cannot meet the demand, smart meters have at least three more sanctions available.

      1) Surge Pricing. That's already being introduced, hilariously being described as 'paying' you to shift your peak demand. Sunday Lunch at 2am, tumble dryer at 3am, Fire Brigade at 4am?
      2) Load Limiting. Use too much and your supply will be tripped until you obey your smart meter's edict.
      3) If all else fails, then rota blackouts can be applied via smart meters. But only for the little people, and perhaps avoidable by those who elect to pay a hefty surcharge for one of the 'Non-Interruptible, Peace of Mind' tariffs which may well be introduced at some point.

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    5. I downloaded the smets2 spec and I haven't found anything saying 'load limiting'. I did find a section on an Auxiliary Proportional Controller. This appears to be to control the charge rate for an EV or home battery system. It doesn't control the main circuit.

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    6. i>> I downloaded the smets2 spec and I haven't found anything saying 'load limiting'.

      Perhaps the document rendered differently on your device, but the Load Limiting information is definitely there, e.g. in Section 5.5.6.

      Just scroll down or search for the the following text:-
      ==========
      5.5.6 Load limiting
      ESME shall be capable of determining when the Active Power Import [INFO](5.7.5.4) is above, for the Load Limit Period(5.7.4.19), the Load Limit Power Threshold(5.7.4.20) and on such an occurrence ESME shall be capable of:
      i. generating an entry to that effect in the Event Log(5.7.5.16);
      ii. generating and sending an Alert to that effect via its HAN Interface and its User Interface;
      iii. counting the number of such occurrences in the Load Limit Counter(5.7.5.18); and
      iv. Disabling the Supply in circumstances where the Load Limit Supply State(5.7.4.22) is configured to require Disablement
      ==========
      Basically, it means that if you draw more power than is permitted for more than a certain number of seconds (the Load Limit Period), then your smart meter will cut off your supply for a certain number of seconds (the Load Limit Restoration Period).

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  4. Re the "smart meter" IHD - worth bearing in mind that gas usage is only updated every 30 minutes as opposed to every 30 seconds for electricity. That makes it pretty much useless for working out how much things like gas hobs are using in day to day usage.

    The amount of nonsense spewed out the media is frankly unbelievable - crap like ovens using the maximum power they're rated at ALL THE TIME! There's another load of bollox today about how "Sunday roasts" are going to cost you £5 to cook and xmas dinner costing a tenner. Only if you leave the bloody oven open, ever heard of insulation?

    Most modern ovens will use 2-2.5kW to heat up on the "fan" setting then after that it averages out at about 800-1.5kWh depending on model and volume.

    Volume is (unsurprisingly) the driving factor so things like "air fryers" which usually have a roasting function as well are very useful in reducing costs. For example 500g of homemade chips cost me 14p to cook in the "air fryer" on Friday compared to nearly double that for a new oven for frozen (oven) chips. Same time to cook, base product (spuds) cost around 20% of the frozen stuff, so a not insignificant saving.

    As an aside pretty much anyone who has a meter less than 25 years old will find it has a "radio cutout switch" for remote disconnection, so that's nothing new.

    AFAIK "load-limiting" is not supported on any SMETS2 single-phase "smart meter" - ie it won't affect any domestic consumer apart from those who have a requirement for exceptionally high current (ie they have 3-phase), which last time I checked was under 0.4% of households.

    ReplyDelete
    Replies
    1. Indeed, we have gas central heating and a gas oven/hob. Heating food will result in the kitchen being heated (its also main living room), so all we spend on gas for cooking will be pretty much identically not needed to spend on gas for heat in that room.

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    2. I'd agree if you were using electric but you have to factor in how much of the heated air you need to vent when using gas appliances to avoid CO poisoning, so its not quite a zero-sum game for most people.

      Of course if you have a heat recovery system (virtually nobody in the UK does) then its not all wasted heat. As an aside if your dryer is venting outside you can recover a lot of that heat fairly easily, not so easy with condensing dryers.

      Nor do most people have heat recovery on water, despite it being very simple to do for things like showers - double piping basically (for those interested), outside pipe takes waste water, internal pipe is cold water feed to tank/boiler which picks up heat from the warm waste water draining away. Great idea, cheap as chips to do, not required by UK building regs so doesn't get fitted by most builders.

      All adds up in terms of but requires basic insulation standards which the vast majority of the UK housing stock don't meet.

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    3. Also a couple of blog things :

      1) When's the battery getting connected? I think we're all interested in how that goes in terms of practical usage from someone who is a techie rather than the average punter. I can read meaningless blurb on this elsewhere :)

      2) Starlink updates - does it reliably do what it says on the tin over time/is it worth the cash etc? I may have missed updates, all I remember is a couple of posts you made when it was installed & no more. I for one would like to hear your opinion now you've had it running for a while.

      We digress :)

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    4. > "AFAIK "load-limiting" is not supported on any SMETS2 single-phase "smart meter" "
      Not so. Read the specifications and you'll see that Load Limiting, Load Shedding, Surge Pricing (aka Time Of Use Tariffs) and lots of other nasties have been built in to all smart meters in the UK.

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    5. You digress, battery Wednesday, and Starlink appears to "just work" and be reliable (I switched all my streaming TV to go via it, and no problems), and I'll be doing something smarter for de-CGNATing it in due course.

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  5. A plug-in power meter is useful. I've got a Zhurui PR10 after reading a review by someone who had access to professional measurement equipment for comparison. A lot of them don't measure power factor well. In the days of just resistive and reactive loads that was easy, but lots of kit these days mangles the current waveform so badly that the current component that isn't contributing to real power drawn is hard to measure.

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  6. I really have no idea what people have against smart meters, in particular the cut off function?? Even if you have a ye-olde-whirry-do-darr meter, they can still cut you off, even from outside the property, same for water, gas etc. Yes it makes it easier, but if you fail to meet the terms of your agreement, then tough, either pay up or get disconnected. Seems pretty binary to me.

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    1. That's fine until someone hacks the system and disconnects everyone and bricks the meters. Imagine how long it would take to get everyone's supply back on if it meant a visit to fix the meter.

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    2. Well, in that "emergency" scenario I suspect a substantial number of people would take it upon themselves to remove the failed equipment from the equation, regardless of the legality of such an approach.

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  7. What would be useful is to standardise on the units for measuring usage of electrical items. Having energy ratings of A++, A+, etc is fairly meaningless really. Appliances should show an indicative/average kWh figure.
    In the same vein, energy providers always give you an annual estimated usage cost. Just use the unit price of p/kWh! Petrol stations don't advertise their costs as "will cost approximately £xx to fill your car" - they show price per litre.

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  8. One note: there is one thing that is *more* efficient than the 100% efficient thing which is an electric heater (all heat wasted! but what you wanted was waste heat) and that's a heat pump, since that, like a refrigerator, uses power to pump *more* heat than it uses in power. (Quite how much more depends on the temperature difference between the inside temperature and the temperature of the working fluid, whatever that is, and the heat capacity of that fluid.)

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