Money Saved on Electricity in One Year

[pp05]

I was told they were 12v.

@Saracen: previous time they were not touched. So when they stopped working they were left alone which means they felt there more was than enough light with just 3 working.

[Saracen]

Really? Hadn't noticed

...

I know, it's a shock, innit?

Worth bearing in mind, though, that while most people may be reasonable and relatively honest, some are devious gits, and that applies to both landlords and tenants. Any quantity of expensive bulbs leaves some room for deviousness by both parties. Which is why I said that if I were renting, and wanted expensive bulbs, I'd rather supply my own, and take 'em with me when I left.

Having said that, it was a long time ago when I last rented.

Also, I suppose it somewhat depends on the nature of the property. What I'd expect in a small ex-council house on Humberside would be different, both in spec and rent, from a penthouse flat in London's Barbican. Oh boy, would the rent be different.

[scaryjim]

... Oh boy, would the rent be different.

Yeah, they'd pay you to live in HumbersideEast Yorkshire/North East Lincolnshire*

*delete as appropriate, since the idiocy that created "Humberside" was overturned some time ago and that abomination no longer exists

[CAT-THE-FIFTH]

[peterb]

Just bought some from ledhut, via Quidco. (10% discount + cashback)

[peterb]

Quick update. I bought seven cool white GU10 for my kitchen and 3 warm white MR11 (12V) for the bathroom.

The cool white were a bit harsh, very bright, which might suit a larger kitchen, but too much for mine, so I changed them for warm white which are much better. The lamps they replaced were 35 watts so the total load was nearly 250 Watts. The replacements are claimed to have an equivalent light output of a 50W halogen, but the load now is a mere 28W (4W each)

The bathroom was slightly less successful. The load with three lamps is too low for the power supply, so I have changed 2 out of the three, reducing the power consumption from 60W to about 23W. I will replace the power supply with a lower rated one, which will reduce the consumption to about 5W.

The lights in a bathroom tend to be on for shorter periods of time, so the payback time will be longer, but based on present usage, I expect to have recouped the cost of the kitchen lights in about 12 months, with the majority over the winter period with longer nights.

(and seeing that energy prices seem set to rise, that payback period may be quicker)

[Zak33]

The load with three lamps is too low for the power supply, so I have changed 2 out of the three, reducing the power consumption from 60W to about 23W.

oh the irony hey... such a low drain the power supply doesn't know they're there!

HEY>.. maybe the PSU's need switching ! for efficiency I mean!

[mepooooo]

I changed my bulbs with LED. I made insulation of my house and i started to turn of the lights when I don't use them. I changed some of my appliances with energy saver and my bill now is less with 50%.

[Top_gun]

Great thread.

I tend to find that it's the passive electrical items, such as television and video equipment, who are the real offenders in wasting energy.

For example, a tv, video recorder, freeview recorder and cable box on standby could easily waste £40 a year.

Other examples would include DECT phones and routers.

I'd also like to see more energy labelling on the wider electronic goods so that consumers can make a more informed choice and give incentive to the manufacturers to produce more efficient products like adding an on-off switch. There is only limited information on white goods and some electricals such as television sets.

I'm not ready to switch over to LED lights just yet, mainly because their efficiencies are around 83 to 85% rather than the expected 90%.

[mepooooo]

Of course passive electrical items waste a lot of energy. You cant turn off them when you are at home but for example if you are on holiday you must plug them off.

[Butcher]

I'm not ready to switch over to LED lights just yet, mainly because their efficiencies are around 83 to 85% rather than the expected 90%.

Where are you finding 80%+ efficient LEDs? The theoretical maximum for white LEDs is around 40% and we're nowhere near that yet. They're about as good as CCFLs at the moment - around 10% efficient; still a lot better than the ~2% for an incandescent lamp though.

[Saracen]

Where are you finding 80%+ efficient LEDs? The theoretical maximum for white LEDs is around 40% and we're nowhere near that yet. They're about as good as CCFLs at the moment - around 10% efficient; still a lot better than the ~2% for an incandescent lamp though.

Terminology, probably.

For instance, what is meant by efficiency?

One way to look at it is electrical power in, to light output. But another is relative efficiency of LED against, say, incandescent. In other words, comparative cost-efficiency.

I doubt that consumers give a fig about theoretical energy-conversion efficiency from electricity to light, but they sure as hell give a fig about cost, and that basically means running cost per hour and up-front capital (purchase) cost.

Of course, it's a different calculation yet again for businesses, where maintenance cost also comes into it. If I need to change a bulb, I do it myself. If I run an office, supermarket, etc, with thousands of bulbs, I don't want to spend my life changing them, so if a bulb lasts 5 times as long, I need to spend a lot less time (and therefore labour costs) replacing them. And that, of course, is the justification for the high initial cost for business, but it matters not at all to most consumers.

So that 80%-ish figure may well refer to the relative running cost.

For instance, the Lighting Industry Federation suggest, as of 2009, LEDs can produce 50-100 lm/w. The comparative figure for incandescent is 8-14lm/w. And, at the same time, the lifetime of LED is rated at 20,000 to 50,000 hours, compared to 400 to 2000 for incandescent, by the same source.

Taking the mid-point, you have 11 lm/w compared to 75lm/w, which is roughly one 7th of the electrical power for a given output of lumens. Those output figures, by the way, came from the Parliamentary Office of Science and Technology, dated 2010, and the tech is improving all the time.

[Top_gun]

Saracen is right, I've based the efficiency on lumens per watt for both LED and CFL's for comparison purposes.

The efficiencies are getting better as this link shows Philip's prize winning LED bulb.

I have heard recently that one lab has managed to produce 260 lumens per watts.

[Saracen]

....

I have heard recently that one lab has managed to produce 260 lumens per watts.

I know MIT hit figures something like that, but it's a lab environment, not a commercial product. And as the frequency of light created depends on the gap size, and that experiment, IIRC, required a very small gap size, the LED created may well not be useful for commercial application, or at least, not in the phosphor-filtered design on most most bulbs.

It may show the direction for further future development, though.

[Top_gun]

I fully agree.

[pp05]

The problem for LED in particular is there are no standards.