Can light bulbs make a difference?

[Dave2002]

Many of us are now getting to be more heat and energy aware than in previous times.

Yesterday I noticed that I'd left a bedside light on for most of the day. The lamp itself includes a dimmer which works when I touch the casing. Then I noticed that the bulb was actually an old style 100 Watt light bulb. So at our current day time rate, let's assume that was at least 10 hours, that would have cost around 40p - since that is the per kWh rate we pay.

In the darker months, lights do tend to get left on, so if we assume that this might happen for 100 days a year [adjust to taste ...] that would be £40 cost.
I tried LED bulbs in the lamp - but of course the ones I have to hand aren't dimmable, so they did go on, but didn't turn off.

Next step - what about buying new dimmable - roughly equivalent bulbs? I found some 12 Watt LED bulbs - 2 for around £10 which look possibles.
ASIN B08SYTZXPT
So for an outlay of £10 - if this works, I can reduce the risks of light left on costing me an arm and a leg in the future.

I have tended to ignore lighting as generally insignificant - and mostly we do have low energy bulbs throughout - so it was just this one bulb which concerned me. Also, regarding costs, as we have PV panels, the likelihood is that we wouldn't have actually incurred much additional cost anyway during daylight hours.
However with the fairly recent sharp rises in energy prices others might also want to consider whether light bulbs really are insignificant cost wise.

[Frances_iom]

I have tended to ignore lighting as generally insignificant - and mostly we do have low energy bulbs throughout - so it was just this one bulb which concerned me. .

take 1 yr = 10000hr (simple overestimate thus 1W continuous = 10kWhr - the cost of these seems very variable - the IoM is capped at abt 29p but in UK with all the hidden taxes + rakeoffs for nominally green products, probably double thus a 10W lamp left on = prob a little under £50 per year - for your electronic switched lamp the on/off switch is a continuous drain prob around 1 W thus £5 pa for convenience.

[Serial_Apologist]

Many of us are now getting to be more heat and energy aware than in previous times.

Yesterday I noticed that I'd left a bedside light on for most of the day. The lamp itself includes a dimmer which works when I touch the casing. Then I noticed that the bulb was actually an old style 100 Watt light bulb. So at our current day time rate, let's assume that was at least 10 hours, that would have cost around 40p - since that is the per kWh rate we pay.

In the darker months, lights do tend to get left on, so if we assume that this might happen for 100 days a year [adjust to taste ...] that would be £40 cost.
I tried LED bulbs in the lamp - but of course the ones I have to hand aren't dimmable, so they did go on, but didn't turn off.

Next step - what about buying new dimmable - roughly equivalent bulbs? I found some 12 Watt LED bulbs - 2 for around £10 which look possibles.
ASIN B08SYTZXPT
So for an outlay of £10 - if this works, I can reduce the risks of light left on costing me an arm and a leg in the future.

I have tended to ignore lighting as generally insignificant - and mostly we do have low energy bulbs throughout - so it was just this one bulb which concerned me. Also, regarding costs, as we have PV panels, the likelihood is that we wouldn't have actually incurred much additional cost anyway during daylight hours.
However with the fairly recent sharp rises in energy prices others might also want to consider whether light bulbs really are insignificant cost wise.

Quite right too! I tend to think in very judgemental terms about all those people, influenced one imagines by 1990s TV makeover programmes, had multiple ceiling light fittings installed. One of my neighbours has eight of such in his living room, all of them on most evenings, and sometimes with his dimmer switch on at maximum power, giving the appearance of a hospital operations room and leaching colossal amounts of daylight intensity out into the night air. LED lights seem to emit far more light (lumieres?) than the old bulbs - would I be right?

[Lordgeous]

Gradually changing all bulbs in my 3 storey house. Can't say I like the rather 'cold' light, compared with older 'warm' types, and dimmable versions are rather expensive, but hey-ho, have to do our bit. Trouble is, I have a huge store of filament bulbs, some inherited from my late dad. We both bought in bulk!

[Serial_Apologist]

Gradually changing all bulbs in my 3 storey house. Can't say I like the rather 'cold' light, compared with older 'warm' types, and dimmazble versions are rather expensive, but hey-ho, have to do our bit. Trouble is, I have a huge store of filament bulbs, some inherited from my late dad. We both bought in bulk!

You could of course keep them specially for those in evenings your like to enjoy in the presence of your own company - as do I: no slur implied!

[Petrushka]

I had all the bulbs changed in my house in one go a couple of years ago and the difference was immediately apparent on checking the smart meter. My instinct is that the cost of leaving the lighting on is insignificant. I usually leave a downstairs light on in another room for security reasons if I'm in a different room.

The real killer though, are the florescent lights in the kitchen which have been there for years and which chew up electricity. There's not a lot I can do about them right now except to remember to keep them on only when needed.

[Lordgeous]

I had all the bulbs changed in my house in one go a couple of years ago and the difference was immediately apparent on checking the smart meter. My instinct is that the cost of leaving the lighting on is insignificant. I usually leave a downstairs light on in another room for security reasons if I'm in a different room.

The real killer though, are the florescent lights in the kitchen which have been there for years and which chew up electricity. There's not a lot I can do about them right now except to remember to keep them on only when needed.

There are LED replacements now - very expensive!

[kernelbogey]

[from OP] Yesterday I noticed that I'd left a bedside light on for most of the day. The lamp itself includes a dimmer which works when I touch the casing.

Am I right in thinking a dimmer, when dimmed, consumes as much electricity as when the light is fully on? (I l last studied physics 62 years ago ).

[Dave2002]

Re quality of light - sometimes the so-called warm light is OK, while in other areas the cooler (hotter colour temperature) lights are better and brighter. However these sometime have a very harsh bluish tinge. If these are going to be used with shades which effectively change the colour these may be OK, but it varies.

Re the couple I've ordered, there is a comment on the product site about possible noises from the internal dimming unit. This would probably render them unacceptable to us in the particular application, but I thought it was worth trying - as there is no certainty that they will be unsuitable, and if they work they'll be good to have.

We do have other lights, including some high powered halogen uplighters, but those are never if we can help it, left on, and only in specific rooms and for reasons which justify their use.

[Dave2002]

Am I right in thinking a dimmer, when dimmed, consumes as much electricity as when the light is fully on? (I l last studied physics 72 years ago ).

Probably not. There are several designs of dimmer. Earlier designs perhaps just diverted current via another load- such as a resistor, but that is not how the newer ones work. The complication with LEDs is that different types of LED need different types of dimmer, though some dimmers can work with multiple LEDs. Mostly they work by chopping up the AC waveform.

Similar kinds of issues apply to voltage converters and power supplies. In the past some may again have dropped current through a load or a step up/down transformer, but now many such devices use high frequency switching - maybe include a transformer in the circuit and then bring things back down to the level the appliance is going to need. Also depends whether they supply AC or DC. Designs really have changed a lot in consumer equipment over the last 20 or so years.

[oddoneout]

Am I right in thinking a dimmer, when dimmed, consumes as much electricity as when the light is fully on? (I l last studied physics 72 years ago ).

It used to be the case that dimmers didn't save energy when the light was dimmed but things have moved on https://makemesustainable.com/do-lig...s-save-energy/

[Dave2002]

It used to be the case that dimmers didn't save energy when the light was dimmed but things have moved on https://makemesustainable.com/do-lig...s-save-energy/

I am puzzled about the comment in that article that a 60 Watt bulb uses 0.36 kWh if left on for 24 hours. Is there some hidden factor which i've not taken into account,some light/electricity conversion factor perhaps, or is there an assumption about some other factor - RMS factors for example? Surely 60*24/1000 = 1.44 which would be the calculation I'd use and the units would be kWh.

[Bryn]

Some of the early LED lightbulbs had rather short lives and were fairly pricey compared with the current[sic] situation. Most of the Osram brand LED bulbs I bought in the early days (or back in the day ) lasted only a few months of use. More recently I have opted for those found in Poundland (a pack of 3 for £4). They give quite enough light for my purposes and, so far (in the past three years) none have failed. Recently, I discovered that just one bulb in the house was still an old compact fluorescent type. It was in a very little-used area between the kitchen and utility room, so I had basically overlooked it. That bulb. too, has now been replaced with one of the cheap LED options. I have become very frugal in my use of both gas and electricity, these days, most electricity is used for music reproduction, computer use, microwave and (the heaviest consumer) gogglebox, though the latter effectively also functions as a room heater when in use. Turns out I am several hundred pounds in credit with Good Energy, despite my DD being less than £70 a month. I can't see that level of credit lasting much longer though.

[oddoneout]

Some of the early LED lightbulbs had rather short lives and were fairly pricey compared with the current[sic] situation. Most of the Osram brand LED bulbs I bought in the early days (or back in the day ) lasted only a few months of use. More recently I have opted for those found in Poundland (a pack of 3 for £4). They give quite enough light for my purposes and, so far (in the past three years) none have failed. Recently, I discovered that just one bulb in the house was still an old compact fluorescent type. It was in a very little-used area between the kitchen and utility room, so I had basically overlooked it. That bulb. too, has now been replaced with one of the cheap LED options. I have become very frugal in my use of both gas and electricity, these days, most electricity is used for music reproduction, computer use, microwave and (the heaviest consumer) gogglebox, though the latter effectively also functions as a room heater when in use. Turns out I am several hundred pounds in credit with Good Energy, despite my DD being less than £70 a month. I can't see that level of credit lasting much longer though.

I've never been keen on lending energy companies my money, and this makes me even less inclined to do so, given recent events. https://www.theguardian.com/business...redit-balances
I would rather save money in my own account, rather than the energy company, against future bills, although I know that that is the argument for allowing/encouraging customers to build up credit during the low demand times of the year. Now that I've been switched (not at my request or wish, as previously mentioned) to "fixed" monthly DD rather than paying for what I've actually used each period, I will need to keep an eye on the balances. Doesn't feel like progress as I had the same issue with nPower 15 years ago and eventually switched to another company when requests to repay credit balances were repeatedly blocked.
Back OT, a visually impaired person I know was telling me how much difference she had noticed to her power consumption since switching her lights to state of the art low energy ones, with the added bonus that the light quality was also much better. She was rather surprised as they weren't replacing incandescent bulbs, however turns out she had been using several halogen(the supposedly lower energy versions) bulbs (due to needing bright light), so that would explain it I imagine.

[ardcarp]

I've never been keen on lending energy companies my money

I'm not either. I have to say though that Octopus Energy (a very ethical company I think) has twice contacted us to suggest we reduce our Ditect Debit to them. I think that's pretty good.

On the subject of LED bulbs, I imagine the 12 volt ones (available for caravans and boats) must be uber economical....but I don't know the physics. You can get warm white, and fluorescent strip LED replacements at a quite reasonable price. Try Boatlamps https://boatlamps.co.uk/

You can skip all the navigation light stuff and just look for ordinary caravan-style internal lighting, eg the fourth paragraph.