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Do light dimmers save much on the Electricity bill?

  • 16-02-2011 6:39pm
    #1
    Registered Users, Registered Users 2 Posts: 1,584 ✭✭✭


    Hiyas, Just wondering do dimmers save much on the bill? I LOVE dimmers as i am a big fan of warmly lit rooms IE my chandalier is on a dimmer and i normally set it to maximum dim. Max blows me eyes out.
    Does this on a purely financial level save much money?
    If you dim to 1/4 light on two 5 bulb 60 watt chandaliers do you save 3/4 on the ESB bill?:confused:
    not a scab just wondering !


Comments

  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    ronan45 wrote: »
    Hiyas, Just wondering do dimmers save much on the bill? I LOVE dimmers as i am a big fan of warmly lit rooms IE my chandalier is on a dimmer and i normally set it to maximum dim. Max blows me eyes out.
    Does this on a purely financial level save much money?
    If you dim to 1/4 light on two 5 bulb 60 watt chandaliers do you save 3/4 on the ESB bill?:confused:
    not a scab just wondering !

    Your sure to reduce the loading somewhat. Probably would save the 3/4 of the lighting wattage alright. Or close to it anyway. But you wont of course reduce your overall esb bill by 3/4, just 3/4 of what that light fitting itself is using while dimmed to 1/4 brightness.


  • Registered Users, Registered Users 2 Posts: 1,584 ✭✭✭ronan45


    robbie7730 wrote: »
    Your sure to reduce the loading somewhat. Probably would save the 3/4 of the lighting wattage alright. Or close to it anyway. But you wont of course reduce your overall esb bill by 3/4, just 3/4 of what that light fitting itself is using while dimmed to 1/4 brightness.

    HI robbie yes of course not the whole bill but the lights that are in use at that moment in time. Hmmm SO I wonder.. would a fully dimmed bulb be the equivalent of an energy saving bulb ! Possibly not far off !
    Cheers rob :)


  • Registered Users, Registered Users 2 Posts: 6,995 ✭✭✭Sofiztikated


    You're still losing a lot of energy to heat.

    Why not try dimmable CFL's?


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    ronan45 wrote: »
    HI robbie yes of course not the whole bill but the lights that are in use at that moment in time. Hmmm SO I wonder.. would a fully dimmed bulb be the equivalent of an energy saving bulb ! Possibly not far off !
    Cheers rob :)

    Yes it would be close enough, although dimmable low wattage ones are available also, which would be even lower wattage. Probably not suitable for your chandalier though looks wise.

    One experiment you could do is turn off everything in the house and view your esb meter to see its stopped. Then turn on the light up to full brightness and see notice the meter rotatation speed. Now dim it fully down and see the meter slowing, it will be easier to see it happen if you watch the meter and someone else dims the light. Its easier to see the speed slowing if nothing else is on.


  • Closed Accounts Posts: 466 ✭✭beanie10


    I was told years ago that dimmers use up power, the more you dim it the more power it uses hencr the buzzing noise. I could be wrong.


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  • Registered Users, Registered Users 2 Posts: 419 ✭✭eoghan.geraghty


    Dimming incandescent bulbs will save you very little, nowhere near as efficient as a cfl bulb.


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    beanie10 wrote: »
    I was told years ago that dimmers use up power, the more you dim it the more power it uses hencr the buzzing noise. I could be wrong.

    I was thinking of that exact same thing myself when writing my first reply, but what actually happens is the on time to off time in the dimmer is varied, this is how the light is dimmed, its the increased switching of and on that causes the buzzing. I think its worse with cheaper dimmers. Some can even cause buzzing in the bulb filament


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Dimming incandescent bulbs will save you very little, nowhere near as efficient as a cfl bulb.


    I dont think some chandaliers look great with cfl`s though.


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    beanie10 wrote: »
    I was told years ago that dimmers use up power, the more you dim it the more power it uses hencr the buzzing noise. I could be wrong.


    I thought the buzzing noise increases and comes from the bulbs/light fitting and not the dimmer???


    or am I wrong???:confused:


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    paddy147 wrote: »
    I thought the buzzing noise increases and comes from the bulbs/light fitting and not the dimmer???


    or am I wrong???:confused:

    That does happen alright, i mentioned it in post #8 i think


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  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    Dimming incandescent bulbs will save you very little, nowhere near as efficient as a cfl bulb.
    This is very true.

    However in my opinion CFLs do not produce a very nice light. I agree that they are very effective and suitable in many circumstances, but not in a kitchen, dining room, TV room etc.

    The type of light that people want to dim is generally a light that would look appalling with a CFL! I use them in the utility room, garden shed, side light on a house, driveway lights etc.

    I think many people get too hung up on the energy consumption from lighting of domestic premises. In general lighting only represents a very small portion of the electricity bill for the average home.


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    Dimming incandescent bulbs will save you very little, nowhere near as efficient as a cfl bulb.


    Dimmable 15W CFL bulbs,1 on the right is dimmed by around 50%.;)


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    2011 wrote: »

    The type of light that people want to dim is generally a light that would look appalling with a CFL!




    I think many people get too hung up on the energy consumption from lighting of domestic premises. In general lighting only represents a very small portion of the electricity bill for the average home.


    I have to object to both comments.


    CFL bulbs are now being made in propper warm white and are fully dimmable too (see my pic above).





    My leccy bils have plummeted down since changing every bulb in my house over to LED and CFL.

    And as a well known supermarket store says ......."Every littlle helps".


    Or to quote Weeman from Jackass...."Its not much,but its somethin".


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    This is very true.

    However in my opinion CFLs do not produce a very nice light. I agree that they are very effective and suitable in many circumstances, but not in a kitchen, dining room, TV room etc.

    The type of light that people want to dim is generally a light that would look appalling with a CFL! I use them in the utility room, garden shed, side light on a house, driveway lights etc.

    I think many people get too hung up on the energy consumption from lighting of domestic premises. In general lighting only represents a very small portion of the electricity bill for the average home.

    The CFL being more efficient part is true.
    Im not sure its true to say dimming a 100w bulb does not reduce its running cost though. It is true to say a CFL is more efficient, but they are 2 different things being confused. How efficient a CFL is has no bearing on whether dimming an incandescent bulb will reduce its watts usage. If a 100w bulb is dimmed to 20 percent its full brightness, it must have a fair drop in watts used.


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    paddy147 wrote: »
    My leccy bils have plummeted down since changing every bulb in my house over to LED and CFL.

    With the amount of lights you have in your house im not surprised:pac:


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    robbie7730 wrote: »
    With the amount of lights you have in your house im not surprised:pac:


    Indeed.:pac::D

    Im even in the process of changing over from the Bayonet fitment 11w CFL bulbs to 3w Led bulbs now,nice lamp shade or fitting over them and the light is still nice.


  • Registered Users, Registered Users 2 Posts: 1,584 ✭✭✭ronan45


    paddy147 wrote: »
    Indeed.:pac::D

    Im even in the process of changing over from the Bayonet fitment 11w CFL bulbs to 3w Led bulbs now,nice lamp shade or fitting over them and the light is still nice.

    So these bayonet bulbs LED are they as nice as the standard ones? LED bulbs never heard of them!


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    ronan45 wrote: »
    So these bayonet bulbs LED are they as nice as the standard ones? LED bulbs never heard of them!


    Depends on a persons personal taste,but doesnt bother me.

    When lit,it looks like a bit of a mini UFO hanging below the ceiling.:D


    So far,anyone who has been in my house and seen them,has commented on them and that they look like a UFO and kinda funky.

    All Im interested in,is that they are 3w and give off good light,thats all that matters to me.


  • Registered Users, Registered Users 2 Posts: 10,952 ✭✭✭✭Stoner




  • Registered Users, Registered Users 2 Posts: 1,584 ✭✭✭ronan45


    Stoner wrote: »

    Cheers Stoner!:D

    SO IT DOES SAVE A HELL OF A LOT !
    Dimmer Advantages

    Dimmers also save money. A 50 percent reduction in the light level can result in a 40 percent cost savings on electricity. Dimmed light bulbs also last longer than those operated at full power.



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  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    robbie7730 wrote: »
    Im not sure its true to say dimming a 100w bulb does not reduce its running cost though.

    I never suggested that it would not reduce running costs.

    How efficient a CFL is has no bearing on whether dimming an incandescent bulb will reduce its watts usage. If a 100w bulb is dimmed to 20 percent its full brightness, it must have a fair drop in watts used.

    I agree and did not suggest otherwise.


  • Registered Users, Registered Users 2 Posts: 1,375 ✭✭✭DoesNotCompute


    paddy147 wrote: »
    Indeed.:pac::D

    Im even in the process of changing over from the Bayonet fitment 11w CFL bulbs to 3w Led bulbs now,nice lamp shade or fitting over them and the light is still nice.

    +1000

    LED bulbs are da bomb :cool:

    I'm using 6W Pharox LED bulbs myself in the upstairs landing & toilet, downstairs entrance and toilet. Nice light off them, very efficient, cheap to run, and they're very bright considering they're only using 6W.


  • Registered Users, Registered Users 2 Posts: 1,375 ✭✭✭DoesNotCompute


    ronan45 wrote: »
    Dimmers also save money. A 50 percent reduction in the light level can result in a 40 percent cost savings on electricity.


    How true is this though? Surely the dimmer is using energy, as it is essentially a big resistor, and when the dimmer is at, say, 20% any current that would have been passing through the bulb at full power, is instead being converted into heat (current meets resistance and heat is produced) and sound energy (buzzing noise), thereby not actually saving any money?

    don't think i've explained that very well, but you get the idea?


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    +1000

    LED bulbs are da bomb :cool:

    I'm using 6W Pharox LED bulbs myself in the upstairs landing & toilet, downstairs entrance and toilet. Nice light off them, very efficient, cheap to run, and they're very bright considering they're only using 6W.


    I like the looks of them.

    Whats the light quality like on the bulbs you are using?

    Are they a propper warm white,and would they be as bright as a normal 60W bulb?

    Thanks.:)


  • Registered Users, Registered Users 2 Posts: 1,375 ✭✭✭DoesNotCompute


    Light quality is good, they come in warm white, not sure if they come in daylight white or cool white. They are just as bright as a 60W bulb.

    The light off of them can be a bit "unnatural", and tends to be directional, pointing in a conical manner, rather than in all directions. You don't really notice this though, if you put a light shade around them.

    Here's a video though: http://www.youtube.com/watch?v=3-OJOkbHBGw

    They cost a bomb though, €25 a pop :eek:

    And I'm not sure if they're protected against voltage spikes/surges


  • Registered Users, Registered Users 2 Posts: 5,420 ✭✭✭.G.


    How true is this though? Surely the dimmer is using energy, as it is essentially a big resistor, and when the dimmer is at, say, 20% any current that would have been passing through the bulb at full power, is instead being converted into heat (current meets resistance and heat is produced) and sound energy (buzzing noise), thereby not actually saving any money?

    don't think i've explained that very well, but you get the idea?

    Modern dimmers use triacs or thyristors as well as resistors and they limit the amount of current flowing in the circuit.

    Less current=less power=less money


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    I never suggested that it would not reduce running costs.




    I agree and did not suggest otherwise.

    I was just going by your post number 12. If you say something which had 2 parts is true i`d assume you agree with both parts. No big deal really. Probably just my useless reading as usual:)


  • Closed Accounts Posts: 76 ✭✭GarRoIT


    I don't know if it would save electricity or anything, but electricity is charged at 1 unit per 1000 watts per hour or 1 unit = 1KW/h A unit of electricity costs between about 12c and 15c and a 100watt buld uses 100watts per hour, so a 100 watt bulb at full power costs you about 14 cent every 10 hours or 1.4cent per hour so its not much of a saving really, it looks nice though.


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    How true is this though? Surely the dimmer is using energy, as it is essentially a big resistor, and when the dimmer is at, say, 20% any current that would have been passing through the bulb at full power, is instead being converted into heat (current meets resistance and heat is produced) and sound energy (buzzing noise), thereby not actually saving any money?

    For the first part about dimmer if it was a resistor.
    Well if you have a 100 watt bulb, this has a resistance of about 530 ohms when its on(resistance far lower when its cold). Now put in a resistor of 1000 ohms in series with the bulb. Now you have roughly 0.15 amps flowing, in the circuit. The bulb now outputs (I^2xR) 530 x 0.15 x 0.15=11 watts. The resistor now outputs 1000 x 0.15 x 0.15=22 watts. This would be a lot of watts for a resistor, and it would give off 22 watts of heat like you suggest, but still the overall watts of the circuit is 33 watts instead of 100 watts.

    But as i said in post #8 i think, and i think stoner put a link to something similar, dimmers dont use resistors to dim the bulb, they use on off switching of the supply to the bulb. So the more the ratio of off to on, the dimmer the bulb, and watts are only being used during the on time.


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  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    paddy147 wrote: »
    CFL bulbs are now being made in propper warm white and are fully dimmable too (see my pic above).
    I agree that CFL lamps have a higher efficacy (better lumens to watt ratio), can be dimmed and are available in "warm white".

    In terms of light quality I feel that they are not as good as say a 12V dichroic lamp.

    My leccy bils have plummeted down since changing every bulb in my house over to LED and CFL.
    Well you must have a lot of lights on a lot of the time them!

    I live on my own and I generally have lights only on in 1 room at a time. At most I would guess that I use far less than 100 watts of lighting for far less than 6 hours a day. In other words 0.6 of a unit per day at a cost of €0.12 per day which is well under €50 per year in lighting costs. In the rooms that I spend most of my time in I have dimmers which provide further savings.

    Now I could go and change all of the lamps in my home for CFLs or LEDs and after a few years I would break even. I have some very nice lighting in my house (thanks Bob Bushell) and I feel that it is worth an extra 10 or €20 per year to get the quality of light that I want. Each to their own I guess.

    I have some CFLs in my home in rooms like the utility etc.

    I have small energy bills relitive to others because I focus on saving energy on appliances that use much more energy than I use on lighting.

    Stoners link above clearly shows that a dramatic savings can be made on lighting but only if you have large lighting bills (as some people do).


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    2011 wrote: »
    Well you must have a lot of lights on a lot of the time them!

    Well having a young family usually means that kids leave lights on alot.
    But Im teaching them (or at least trying to anyway) to turn lights off in rooms where they are not playing in or using.

    I do have alot of lights in my house,as its a large house,but now that everything is LED and CFL,this has saved alot.

    My kitchen appliences are also A-Rated too so that helps too..


    Every little helps.:)


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    If you have a lot of downlighters of the halogen 60 watt type then they would run up a bit of a bill alright.


  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    paddy147 wrote: »
    Well having a young family usually means that kids leave lights on alot.
    I know what you mean.
    My kitchen appliences are also A-Rated too so that helps too..

    I think you might find that this is making more of a saving than the lights.

    It is items like the fridge, washing machine, dishwasher, immersion etc. that will make up most of the average electricity bill.

    I also think that some LED and CFLs are so expensive that they pay back time is so long that it is simply not worth it.

    I would agree that energy saving lamps have made massive advances recent years.


  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    robbie7730 wrote: »
    If you have a lot of downlighters of the halogen 60 watt type then they would run up a bit of a bill alright.

    I guess you mean 50 watt?

    I agree, but in my opinion for a domestic premises that is bad lighting design.


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    I guess you mean 50 watt?

    I agree, but in my opinion for a domestic premises that is bad lighting design.

    Yes 50 watt:D. Yes bad design alright, plenty seemed to have them in though.


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  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,641 Mod ✭✭✭✭2011


    robbie7730 wrote: »
    Yes 50 watt:D. Yes bad design alright, plenty seemed to have them in though.
    True.

    I think the "runway look" i.e. lines of downlighters give a really nineties look to a home.


  • Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    True.

    I think the "runway look" i.e. lines of downlighters give a really nineties look to a home.

    I could probably do with runway lights for the flyin of radio control stuff these days now:)


  • Registered Users, Registered Users 2 Posts: 87 ✭✭PrismES


    robbie7730 wrote: »
    The CFL being more efficient part is true.
    Im not sure its true to say dimming a 100w bulb does not reduce its running cost though. It is true to say a CFL is more efficient, but they are 2 different things being confused. How efficient a CFL is has no bearing on whether dimming an incandescent bulb will reduce its watts usage. If a 100w bulb is dimmed to 20 percent its full brightness, it must have a fair drop in watts used.

    See below for savings resulting from dimming

    Amount DimmedPotential Saving1010%2520%5040%7560%


  • Banned (with Prison Access) Posts: 15,858 ✭✭✭✭paddy147


    You can now buy fully dimmable CFL bulbs.They come in an E27 fitment (screw cap)

    I have a few 15W dimmable CFL bulbs in my floor lights and they are very good indeed.:)


  • Registered Users, Registered Users 2 Posts: 4 Martina1981


    Hi,

    Did anybody switch recently to energia electricity provider?
    I spoke to their rep and he said I may save 20 euro per month based on my old bill.
    He said also I do not have to let my landlord know in case if I want to switch to different provider?


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  • Registered Users, Registered Users 2 Posts: 10,952 ✭✭✭✭Stoner


    Zombie thread. You can start a new one if you wish.


This discussion has been closed.
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