Low energy bulbs, the truth according to colin

[colin]

We have been long term users of low energy bulbs in our house, having wall lights just below wooden beams which got hot and having to use lights on even the sunniest days in summer they have been most welcome, but when buying bulbs for new bungalow a few things occured to me, some will be obvious to users of these bulbs but one might not!

The premise around using low energy bulbs has been cost savings and lower co2 usage, but it's not as good as made out, most users will soon find out the early promises of light output don't work and we find for a output equivelent to 60w over the life of a bulb you realy need 15w low energy's.

Next comes life of bulb, the longest bulbs last is little over 2 years(multiple wall lights burn out much more than single lights), and the disposal of low energy's contains much more toxins.

Here comes the one that seems not to be considered, as you sit there on a winters night in a centraly heated house, how much money do you think low energy bulbs save you? I would say nothing! the reason? the low power usage is due to less heat output, but in winter this helps heat your house and if your heating is termostaticaly controled it will compensate for the heat output from the lights!

 

 

[CliveH]

Well said Colin.

 

I was staggered at how toxic these LE bulbs are! - If you break them you have quite a problem as they contain Mercury which even in small amounts is incredibly toxic.

 

Then there is the energy used to make the darn things! - the CO2 input in manufacture is far more than that saved by us during their lifetime.

 

We have some but buy ordinary bulbs now when we can. Main reason is that these LE bulbs take a while to warm up. And this is ruddy dangerous for lighting on the stairs, by steps or by the back door etc.

 

So these LE bulbs are worse than useless in my view. I suspect that LED bulbs will take over (as long as their manufacture does not ruin the planet (lol) )

[Guest Tracker]

All good points Colin - but!

 

I have been using low energy bulbs for over15 years (and they were quite expensive then) and in all that time only two have ever failed. I am still using one that is over ten years old it having been used in four different homes over this period so I can't complain. Being a tight fisted old codger we used to replace all the low energy bulbs with incandescent bulbs when we moved as I still had a good supply of them!

 

Any heat from light bulbs tends to be at ceiling height so any heated air tends to stay up high whereas us mortals without wings need warmth radiated at us at sitting height.

 

The wall mounted thermostat is also at shoulder height and well below the light bulbs.

 

I don't so much buy them for the cost savings but for longevity because I got fed up with buying ordinary bulbs by the dozen and changing them far too often.

 

I agree about the light output though as most of the claimed equivalence is mighty optimistic at best and plain untrue at worst.

 

At risk of being shot down (again) I might suggest that the pollution aspect is over stated. Considering what else, and the volumes of it, that goes into landfill every day low energy bulbs must be an infinitesimal proportion both in volume and potential pollution. Not that I support landfill but until we as a nation are prepared to pay for full and accurate recycling (which inevitably means more and higher taxation to pay for it) it's all that is available to us.

[BGD]

My guess is that in the fairly near future now, both the traditional incandescent bulbs, and the " low energy" ones will be superceded by LED bulbs.

[Guest Tracker]

As soon as very high volume manufacture by several Chinese factories, and with it sensible prices, gets into gear I would imagine Bruce?

[colin]

Just to answers a couple of things richard has commented on.

 

Yes the LE's last much longer than incandescent, but not allways as long as the blurb might suggest, I've just realised we have a couple of reading lamps that are very early LE's, but as I said like incandescent they don't like being multiple wall lamps, which most of ours are.

The heat radiated goes straight up, but this is what happens to most of the heat from your radiators, if you stand on a set of steps (or just stand up in our old house) you find it's much hotter at ceiling level, this is heat gradiant, and the heat from lights contributes pretty much just as well as your radiators, in fact in autumn, due to the high levels of insulation on the new bungalow just switching on lights and using tv was enough to heat up a room.

For the disposal of LE's, at work it is illegal to dispose of them in general waste, proboly the same for disposal at home.

Like clive we have found they can take some time to warm up, even the new 'fast warm up' ones after 12month? will be very slow, for this reason we use incandescent on stairways.

[Guest Tracker]

Fair comment Colin - can't argue with that!

 

PS For all those argumentative and pompous egos out there, and you know who you are, this surely is the best way to discuss any issue - friendly and without insult or any form of belittling the other point of view.

 

The epitome of diplomacy,

 

Rich.

[Brian Kirby]

However, the amount of energy that is converted into heat by low energy, and filament, lamps is not equivalent, which is why you get more light for less work done from the LE lamp.  It does more of its work in the higher frequency, visible, end of the spectrum, and less at the lower, infra red end. 

Also, as a means of heating your home, electricity is very inefficient, and expensive, so even if the wattage of the lamps translated directly into heat, buying that heat in the form of electricity would cost more than buying the same amount of heat via gas.  Whether this is true for coal, wood or oil I know not, but the varying efficiencies of the various kinds of heat emitters would render the calculation meaningless. 

The point, surely, is that by consuming less electricity your bills are lower, and the total generating capacity required at UK plc peak demand is reduced.

Consider also that lighting is used at times when heating is not, so the value any theoretical trade off between heat from lights and heat from heating system is further diminished.

[Rainbow-Chasers]

I feel i can enlighten you on this! I have a friend who knows all about it as he works in energy science - and he stated that low energy bulbs save electricity only when they are left on....that is permanently. The acts of using the bulb as a conventional bulb actually uses more in it's heating up process. This takes some hours too...around six before it starts to recirculate the energy. You can work out for yourselves if you think you will save anything!

 

As for heating the home, go geothermal and don't beleive the tales. That uses an electric pump to pull up the earths heat and use it to heat your home and water. It does either or, not at the same time, but 30 mins timed in and it will chop and change and you won't notice.

 

This in comparison with solid fuels and gas is great! Previous spending on coal was £80/month - geo thermal raised the electric bill by £20/quarter during last winter, or cost £5/ month. It is almost like having gas, it does take 20 mins to warm up in the morning (pulling the heat up) but it has a timer so you just set it a bit earlier! The way forward!

[colin]

Yes I'd forgotten about the warm up, boss would keep turning flouresents off at dinnertime until I told him how much extra it cost *-)

[Brian Kirby]

Rainbow-Chasers' - 2008-12-03 11:35 PM I feel i can enlighten you on this! I have a friend who knows all about it as he works in energy science - and he stated that low energy bulbs save electricity only when they are left on....that is permanently. The acts of using the bulb as a conventional bulb actually uses more in it's heating up process. This takes some hours too...around six before it starts to recirculate the energy. You can work out for yourselves if you think you will save anything! As for heating the home, go geothermal and don't beleive the tales. That uses an electric pump to pull up the earths heat and use it to heat your home and water. It does either or, not at the same time, but 30 mins timed in and it will chop and change and you won't notice. This in comparison with solid fuels and gas is great! Previous spending on coal was £80/month - geo thermal raised the electric bill by £20/quarter during last winter, or cost £5/ month. It is almost like having gas, it does take 20 mins to warm up in the morning (pulling the heat up) but it has a timer so you just set it a bit earlier! The way forward!

Re the light bulbs, I think there may be a few assumptions being made about comparable lamp types.  Can these be stated please?  Just claiming that low energy lamps (and what exactly are these, what type, what wattages, what outputs?) are more economical that general service lamps (GSL) only if left on for 6 hours or more, seems a little rash.  A 15W folded fluorescent is claimed to have the same light output as a 75W GSL, and to last 15,000 hours.  If either is left on, the electricity consumed is watts times hours/1000, in Kilowatt hours, no? 

Is there a possible confusion over the light output, which is below the claimed 75W equivalent until warmed up, and tails off over time?  Mind, GSL lamp performances tail off toward the end of their lives, as well, so not advantage to either, there. 

Can your friend not expand a bit on how he arrives at his conclusion, with some details on the necessary assumptions?

Re the heating: and the minimum area required for the ground heat source is?  And the total, installed, cost of the geothermal system, was?  And the payback time, against your previous actual heating costs will be, taking into account the increased electricity consumption?  Please!

[colin]

Brian the light output of a 15w compact flouresent may be similier to 75w gls for a few months but it rapidly reduces to more like a 60w gls for about 2/3rds of it life(my guess) the last 1/3 about same as 40w. The 15,000 hour life has not proved correct for me, as if I take the average lifespan this would equate to 16hrs per day every day, even with the amount we use lights this is unlikely, but as I said this is for multiple wall lamps, gls lamps burn out a lot quicker its true

I too would be interested in ground source heat pump instalation costs, we considered this but decided not to use for various reasons one was cost, a lot was made be suppliers about cost of putting in the pipes, but we offered to do ourselves as we have the equipment but discount offered was a joke and it made the rest of the system very poor value

[Brian Kirby]

Problem is, Colin, they keep changing and improving!  The figures I gave were from a new lamp that I have as a spare, and I'm sure the last lot I got were only promising around 8,000 hours life.

However, we have a couple of the old 2D lamps still going, after what must now be 15 years.  They don't get a huge amount of use, but I haven't noticed a great deal of dimming in the output.  However even if there is some, (and the technical mags etc bear this out), just use the next size up if output is important, so that it only dims to the level you want!  Should still use less juice, it seems to me.

About half ours is lit by 12V 20W dichroic spots, the rest on one or another kind of miniature fluorescent lamps, mostly 15W, and has been so for about 15 years, so I can't now quote any meaningful comparisons with when it was all tungsten lit.

[vindiboy]

Funny old world ain't it, here we are over fed nice and warm, living in a nice home, expensive vehicles parked on our drives ,holidays abroad etc and discussing saving a few pence on electricity costs on light bulbs 8-)

[RupertGS]

vindiboy - 2008-12-09 10:42 PM Funny old world ain't it, here we are over fed nice and warm, living in a nice home, expensive vehicles parked on our drives ,holidays abroad etc and discussing saving a few pence on electricity costs on light bulbs 8-)

How very appropriate that you say this just as I've started a new thread on what I see is becoming a worrying obsession with a few people.

The real problem is when it goes beyond what most people would class as reasonable carefulness and becomes an all-consuming need to save every penny, to the detriment of one's quality of life and even one's safety.

I've stockpiled a few dozen old fashioned 100 watt and 150 watt light bulbs. I can't stand these awful new low-energy ones - I don't care how much money they save!

[colin]

Thats partly why I started thread, the thoertic cost saving to me of low energy bulbs is about £100 per year, but it doesn't seem it in reality, and for that we produce more toxic waste, and isn't the law changing to make us buy LE's

[Brian Kirby]

I thought there was originally a wider point than cost?  Something to do with reduced CO2?  I don't want to start the climate fight all over again, but if the projected consequences of failing to reduce CO2 production are correct, that is surely a more compelling argument for reducing electricity consumption.