How Much is this Costing Me?

Several years ago, we got a power consumption meter. It plugs into the power point and the device connected to it. It has no smart features , apart from the costings of the kw/h. It displays the total watts measured, and does monitor peak current or peak watts consumed. My circular saw draws 3kw on start up which was a shock to see, even though is sort of soft starts. But once running is not using much at all, around 250 watts, so far lower than I would have thought. It has been a handy little tool to use periodically. It can help you to charge a reasonable amount for the electricity used when making something, and I think we way under estimate how much power is used in the home workshop.

As said, even the simple incandescent filament lamp is not a straightforward calculation.

Being in most cases a coiled coil filament must mean that that it has inductance, so there is phase shift between voltage and current. The calculation is corrected by incorporating the power factor.

Fluorescent lighting can be used to improve the power factor, where the major load is inductive, producing a phase shift opposite to that of the inductive load..

As I am only a simple mechanical engineer, an AMIEE should be able to provide a much more in depth explanation.

Howard.

Edited By Howard Lewis on 08/08/2022 10:27:36

I was desperately trying to avoid a more in-depth explanation! Can we agree that there is no such thing as a simple resistive load, everything has associated inductance and capacitance (even the cables feeding the device), but as engineers we can accept a reasonable approximation?

There are probably a lot more mechanical than electrical engineers reading this so it seems sensible to avoid too much distracting and largely irrelevant (even if interesting to some of us) detail. "How much is this costing me?" also applies to intellectual effort needed to understand the answer!

(Duplicate post)

Edited By Nealeb on 08/08/2022 10:43:28

Surely , the most inefficient use of electrical energy in the home is to create heat directly , ie the oven and immersion heater ?

Although the advertising for smart meters has at times been reprehensible (exploiting grandparents concern over grandchildren) they don't bite so not a major problem. Mine does get a bit confused over summer time and the cost display is a bit off after resetting itself at midnight for a while. As to accuracy when I was away for a week so stable loads (fridge, alarm, radio on standby) the daily readings were within a penny which could be the variation in the fridge and ambient temperature. I think if I add the modem and a security light my base load including standing charge is about £1 / day now.
Having had to get a new fridge last year it is now obvious how much less it uses, and I can see the jump in watts each time it turns on. Just unplugged my microwave and see it uses 6W, that would light up the whole kitchen if it were a LED bulb, Modem is a bit of a pain at 11W. Mains radio uses 5W to keep its channel memory and about 20 running which is probably rather more than a modern one would. When outside I use a solar powered radio.

Oh, the remote smart meter display uses 1W.

As to workshop machine power consumption this might be a reason to get a SuperAdept for the small jobs and forgo the boasting of having a Colchester Triumph. I took my smart display into the workshop and did a five minute turning job, The display didn't even move !W no matter how hard I treadled

With respect Nigel we all become silly old duffers, some of us before leaving school!

Is it relevant that your friend is in a compulsory registration scheme? I think not, particularly as it seems the chap in question is a plumber.

I'm not here to sell smart meters, and my advice to Chris was not to get one. My reasoning is smart meters are a tool, and the smart meter is a tool that doesn't meet Chris's need to understand how much his workshop machines cost to run. I recommended a wattmeter, which does. They're plug and play: buy one with cost calculation built in and and it does the sums too.

By thinking of smart meters as a tool and asking 'will it work for me', just as if I was buying a screwdriver it's not necessary to get entangled in red-herrings like the cost to an independent tradesman of keeping up-to-date with British Standards, or what the Law is for, or what Lenin said, or Internet fraud schemes. It's unhelpful to introduce these into Chris's "what is this costing me?" question.

A few people have commented that smart meters aren't essential. Quite right, but not enough to conclude they're useless or evil. Smart meters make it much easier to keep tabs on the cost of consuming electricity. They monitor consumption and issue alerts continuously, which is extremely helpful to anyone on a tight budget. May not have been critical in the past, but it is now. They're not for well-funded people living in electrically simple circumstances who know how to read an ordinary meter and will do the sums regularly. (As opposed to the experts who know how but can't be bothered!) Smart meters are for the bulk of the population who don't have technical skills, living lives stuffed with difficult decisions, with multiple complex demands on their time and money. They're much more useful to the working millions than to retired Model Engineers like me!

In general I think it best for engineers to avoid taking personal experiences into account. We are not politicians who look ahead and then run sideways like crabs. Evidence and intellectual discipline please, and remember that opinions based on small numbers are always highly suspect. That a Smart Meter is of no use to me doesn't mean they're all rubbish. You have to understand the big picture.

Dave

Strictly true, but in the case of an incandescent filament the associated inductance and capacitance will be very small, less than a microhenry and a few picofarads. At 50Hz a resistive model is rather better than reasonable.

The older electromechanical watt-hour meters measure energy consumed, they do not account for VARs. The newer electronic meters do take account of power factor. The case of wall warts is more complex. The current is drawn in pulses so the waveform is nothing like a sinusoid and contains a lot of harmonics. This is a problem for generators, so the power supplies should contain power factor correction circuits these days. These can be passive, ie, a filter, ot active, usually a switch mode supply controlling input current according to the input voltage.

My experience is that my workshop consumes very little power compared to everyday things in the house. The only thing that did make a noticable difference in the workshop was changing five flourescent tubes for LED tubes. I use about 6.5kWh per day, on average, for everything.

Andrew

Has anyone carried out any similar power consumption checks for a Myford S7 when left running at idling speeds? Sorry but can't supply any details on the SP motor to reveal the model/reference number details as this would involve moving the whole ensemble away from the wall and that is a no-no at the moment.

I changed 6 four foot fluorescent tubes in my workshop for 6 four foot led “tubes”, to me the difference in light output was amazing, I can work in their during the day with the blinds pulled down over the windows to shut out the sun in the hot weather, I know that the rated consumption of the led tubes was considerably less than the fluorescents although I haven’t measured the consumption for comparison so I am happy that I am using far less electricity to light the workshop, it’s got to be the way to go. Dave W

Dave -

Actually the trade registrations do affect us because the holders must recover the consequent direct costs and loss of earnings. So they spread it around their bills, just as they pay for their tools and vehicles.

My point though, is that I should have sought advice before agreeing to have smart meters, and I would would far rather trust an independent builder and gas-fitter than the suppliers' advertising, let alone the wafflings of politicians who barely know energy from power.

I, and no doubt many others, were led to believe we would have to fit them; either voluntarily as I did or not too far ahead, law. So should have asked someone I know understands the matter professionally, but who has no vested political or commercial interest in "smart" meters. However much you denigrate him as a mere "plumber" .

. . .

In any case, does the meter type make a scrap of difference?

I try to limit my gas and electricity consumption as much as possible, as I live in a poorly-insulated Edwardian terraced home and have an energy-hungry hobby.

So I counted what uses electricity if I work until late in the evening in the workshop, which is unheated and lit by two l.e.d flourescent strips. All that are running in the house are the fridge and freezer (under-counter types), oven clock, boiler control unit (and its intermittent fan if the heating is on), broadband modem, and bedroom clock/radio.

No lights, no chargers left on needlessly let alone over-night, no PC or TV on "stand-by" (actually, no TV). When I switch the computer off, I switch off the mains socket too.

The radios in the kitchen and front room (both basic "trannies" ) are still "On" despite the switch being "Off". I realised this by a faint hum from one, and the indicator l.e.d. on the other. I now turn off their mains sockets as well, when not needing them for several hours.

I bought a 'phone intended to allow caller-display and blocking, etc.; found it needs plugging into the mains all the time, replaced it in the carton - must try and sell it.

'

Yes, of course I still need use gas and electricity domestically; but the workshop, radio and PC and by choice. So the type of meter won't make a scrap of difference. How can it, despite the Government's propaganda?

It will be cost that controls us, neither fancy digital display nor conventional, straightforward kW/h counter.

What am I meant to do when I next set the lathe on a long self-acting cut? Run back to the house to read the meter? What is a local power-meter really going to do for me, if I still want to make that part?

'

This all reminds me of a friend who once complained to me the cost of keeping a horse. I replied, "Well, you chose to own two of them, plus horse-box, paddock and stable!" She - far wealthier than me - had to agree, rather ruefully!

.

I have had various conversations with my building-trade pal; on costs.

We agreed that far too many people seem unable to grasp the simple concept of overheads / call-out charges / labour costs. I knew I cost my employer's customers a lot more than even my quite good, gross, wage.

On road fuels, he asked, do we want to save the money by having no social and leisure life; or simply be a bit more careful about our journeys? Similarly with the utilities.

He and I, and probably most of us on this forum, cannot complain too much when there are very many people having to sacrifice so much more than we need.

It's not going to get much better, either, in the foreseeable future.

Edited By Nigel Graham 2 on 08/08/2022 14:08:09

Indeed. If you think running a 750W lathe motor intermittently is expensive, yes try a horse or two. Even a cat or a dog these days seems to cost more in vet bills than my annual medical expenditure on myself. Or a boat. B.O.A.T. Bring Out Another Thousand, aka " A hole in the water you throw money into".

On the other hand, perhaps I should convert my old Drummond lathe back to its original treadle power just in case.

It won't be long before we are 'offered' tarrifs dependant on time of day and wind speed. Next step will be to fix tarrifs so that those on dumb meters will pay more no matter what they do. Telling SWMBO that she can't do the washing until the wind picks up could be difficult. No point getting upset, go with the flow, or as my son says, take a chill pill.

I went all led about two years ago and the improvement in light quality was worth the cost of the tubes, plus I'm saving money on electric, though the cost of the electric has curtailed my use of machines and as the time factor is unimportant to me I've started doing far more jobs manually which takes longer and is more tiring but at least it only costs me the wear on the tools.

Edited By Coggy Clapsaddle on 08/08/2022 14:54:27

Duncan, just over three years ago my fixed term energy contract was up for renewal with Shell Energy, when I looked at the 3 year fixed term contracts on offer, bearing in mind I have an Economy Seven tariff, there was only one that was available for me because I didn’t have a Smart Meter fitted, if I had a Smart Meter there were I think four different Economy Seven tariffs that I could have and all had a cheaper unit price than the one that I was forced to choose. I am resolutely against Smart Meters for all the devious arrangements that they will bring forth, none of them to the advantage of the customer so I opted for the tariff without Smart Metering. The three year tariff that I chose expired at the end of June and now because of the turmoil in the energy markets Shell Energy only offer one Economy Seven tariff and that is regardless of whatever metering you have, so the same price for all customers because of the Offgem price cap, suffice to say that I still resist having a Smart Meter, despite receiving constant emails to try and persuade me otherwise. I felt that when I was restricted to be able to choose only one of five tariffs on offer three years ago that the supplier was acting in a bullying and immoral way trying to blackmail loyal customers, I do realise that nowadays loyalty counts for nothing it’s balance sheets are the only issue that matters to them and they don’t give a damn how they achieve their financial targets. The manipulation via Smart Meters regarding pricing and times that you mentioned will be coming only too soon. Dave W

For us domestic customers we have a Kilowatt hour meter, so power factor doesn't come into it. Straight amp X volt is near enough. It's s either you want to use your work shop or you don't simple as that, avoid the worry and stress. John

I'm not intending to have a go any individuals here, but the conversation within this thread goes to highlight one of the problems we humans have and that is that we can adapt to almost anything, even if it is to our common detriment.

I presume that most of us realise that there is no reasonable explanation with regard to the massive price hikes that have happend and are also scheduled to happen, yet this thread shows that not only are many accepting of it, but we are also chatting amongst ourselves as to how we are going to get along with it and somehow cope with whatever the consequences are.

Saving energy is always the best idea, but I'd like to know how, within the space of six or seven months, an average £1300-£1500 annual home energy bill has more than doubled, with some talk of an increase towards £4000+ by next year.

At this rate, charity, food banks, and soup kitchens are going to become the norm and I'm getting the feeling we're sleepwalking right into that scenario.

Martin.

Just a contrarian opinion on folks' happiness on changing to LED lighting from fluorescent lighting.

The lumens per Watt for LED tubes and (new ish) tri-phosphor fluorescent tubes are very similar. You save power when replacing an old 36W fluorescent tube with a 22W LED dube, but you've still got little more than half the brightness than you would have if you put in a new fluorescrent tube.

I've got 14 36W tubes in my shed for a reason:- I like to be able to see!