working out small energy savings

Energy saving questions in here please

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working out small energy savings

Post by big-all »

to most people its a minefield and quite difficult to work out

changing say 1 x100w[£50 a year to run] light bulb for a 22w[88w equivalent] low energy light bulb will save £38 a year if run for 10hrs average a day over the whole year at 15p a kw unit
even more with a led equivalent at 10w will save a massive £45

in general once you have excluded high power items like heating and hot water then items like computers tvs games consoles that are left on unnecessary
light bulbs changed for more efficient ones are the greatest source off saving all be it at quite a high outlay but any money will be repaid within months on low energy bulbs and 1 to 2 years with led bulbs replacing low energy bulbs or months if replacing a normal bulb

assuming running for 10hrs a day 365 a year and with 15p a kw unit costs it works out at roughly 1p per watt per week at70w [1000div by 70=14.2]

the modern led bulbs in my opinion are quite stylish with shiny twisted aluminium fins a normal bulb shape and size with a normal looking bulb glass visible from underneath

my annual consumption from light bulbs will be less than a weeks consumption in some houses
with all the bulbs in rooms normally used in my house turned on i use 36w an hour if we turn off the hall and bathroom when not in use [4.5w+6w]its down to26w lol
so if you look at the following chart you will see 36w is 25w+10w+1w so £12.50+£5+50p so £18 a year or 26 w is 25w+1w=£12.50+50p= £13

the bulbs i use are a mixture off corn type[many dozen low powered led]old hat now
medium powered but again not nice looking
1.2watt round flat in bulbs and 10w flat square ones in bulbs
i have 4/7/10w bulbs equivalent to around multiply the number by 9 to get normal bulb equivalent so 36w 63w and 90w
tool station sell the 7w for around £13 you can get them cheaper usually from h/k
i will add some links later as its supper time lol

these are the 4w ones £19 for four great for wall light quite bright for reading lamps and rooms with more than one pendant
they come from portsmouth in about 3 days they give a great coverage over say 1.5x1.5metres good coverage at 1.7x1.7m 2x2m dim at the edges
http://www.ebay.co.uk/itm/330813221035? ... 1439.l2649

these are the 7w version excellent at 2mx2m good at 2.5mx2.5m ok at 3mx3m
http://www.ebay.co.uk/itm/7W-B22-Bayone ... 3a78fd24cf

these are the 10w version excellent light for a 3mx3m room good light for a 3.5x3.5 ok at 4m
http://www.ebay.co.uk/itm/2-4-10x-10W-B ... 25765d65fb

as an example my kitchen is 2mx 4.1m 2 x4w bulbs where a touch dim
the actual pendants where at roughly 1/5 and 3/5ths so 2 x7w where to much but with a 7w at the bigger end and a 4w the smaller its a perfect balance :thumbright:

you can also get dimable and down lighter versions along with security light but i will let someone else cover those as i have no experience with them

another point about led lighting is it removes the need to turn lights out for short times so you dont worry about kids leaving lights on unnecessarily as it will cost no more than around 1p a day


1w saving is 50p a year
2w saving is £1 a year
3w is £1.50p
4w is £2
5w is £2.50p
10w is £5
15w is £7.50p
20w is £10
25w is £12.50p
50w is £25
75w is £37.50p
100w is £50
250w is £125 a year
500w is £250
750w is £375
1000w is £500
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Re: working out small energy savings

Post by Colour Republic »

Recently fitted a kitchen for a customer with led tape lights under the kicker boards and wall units, I was telling her how cheap they are to run, then suggested she could change all of her gu10 halogens, some 25 of them. She can now have all the lights in her house on for the cost of runing just 2 of her old bulbs. It was a no brainer for her.
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Re: working out small energy savings

Post by nick200 »

Thanks for that it certainly puts it into perspective! :thumbright:
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Re: working out small energy savings

Post by big-all »

Colour Republic wrote:Recently fitted a kitchen for a customer with led tape lights under the kicker boards and wall units, I was telling her how cheap they are to run, then suggested she could change all of her gu10 halogens, some 25 of them. She can now have all the lights in her house on for the cost of runing just 2 of her old bulbs. It was a no brainer for her.
if you work out the average kitchen with say 6x 50w downlighters [300w] living room say 200w [200w]2 kids rooms 2 hall lights and the bathroom[350w] total 850w per hour thats £425 a year replace with led bulbs to the same level running cost is £47 or put it another way a saving £378 a year
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Re: working out small energy savings

Post by big-all »

nick200 wrote:Thanks for that it certainly puts it into perspective! :thumbright:
a family could save enough money in 5 years to go to florida disney world
5x378= £1890 ok it may be crossing the atlantic by pedalo camping in the swamps but you get the idea :lol: :lol:
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Re: working out small energy savings

Post by kellys_eye »

Much as your figures work out mathematically, real-life situations are usually a lot different. For example you use the 'average' of 10hours/day 365/year. Many lights in your house are not on for any where near these lengths. Holidays even? Perhaps your living room lights but the others.....??? Then there are the costs of the replacement lights - LED lights aren't cheap nor are they as bright as traditional lights. You can often end up using multiple lights to get the same result as the old style. The old filament lights also added HEAT to your home - heat that has to be replaced.

Much like stuffing the loft with insulation there is a point at which more stuffing doesn't necessarily make greater savings. Attention to the big power consumers is, as you mention, the first priority but forgetting to switch the heating off for ONE day can completely negate any savings you might make in a year by 'fiddling' with your lighting.
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Re: working out small energy savings

Post by big-all »

the heat given out is only usefull when its cold otherwise its surplus heat to get rid off
if we assume a 100w bulbs gives out say 50 or 50 w in heats so assume thats say 10 100w bulbs for simplicities sake thats 1kwper hour 500w for light and 500w heat costing 1 unit or 15p
the same amount off light will be 110w with leds with a small amount going in heat perhaps 5%
you now have to generate about 494w[difference between heat outputs]
494 will cost around 7.3p at 15p per kw electric the same energy by gas will be around 2.8p allowing for gas being 1/3 the price but only about 80-85% efficient so in this equazion that 4.5p an hour saving on the heat side plus 89% off the light side at 6.675 add on the heat saving so 11.17pence in every 15p that assuming as much as 50% off the normal light input is heat

yes all my calculations use assumptions as all situations are different for example my dining room lights are on for more than 10 hrs as are the hall lights because i live in a mid terrace where after 9am only reflected light reaches the main windows and by 12oclock the sun will not touch any walls to reflect int the windows
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Re: working out small energy savings

Post by kellys_eye »

Filament bulb wattage ratings refer directly to the HEAT they produced therefore a 100W bulb gives off 100W of heat - the light is a byproduct of the heat! Much like a 1kW element in an electric fire glows red (only a little light in this example) the element still radiates 1kW of heat.

Accordingly if you run 10 off 100W lights in a room you're as good as running a 1kW bar heater - the light is, effectively, free. If you NEED 1kW to heat a room, fit 10 off 100W bulbs and leave the heating off. That way you're getting your light FREE - cheaper than any LED or CFL bulb.....
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Re: working out small energy savings

Post by big-all »

even at 100% its still cheaper to use led and gas
1kw= 15p
same heat with gas 6p plus 110w for the bulbs=1.7p so total 7.7p led bulbs so worst scenario only a
50% saving
then you have the cost off dissipating extra heat when you dont need it :dunno:
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Re: working out small energy savings

Post by kellys_eye »

Yup, can't fault your reasoning or maths b-a :thumbleft:

Shame I'm in an all-electric property :roll: all I can hope for is that electricity prices 'may' fall when shale gas comes on stream. I'm probably going to benefit more from my micro hydro power generation scheme so.... meh.

I can confess to being totally hacked off with CFL prices (£2.99 minimum and even don't get me started on bulbs that are 'odd-shaped' to fit specific lamp holders....) and LEDs aren't worth the gamble - as a gamble they surely are for the moment - for at least another year.

Many houses now have more subdued lighting schemes so savings that are 'possible' are probably more complicated and difficult to come by when addressing lighting as an energy-saving method but I see where your own experiments have encouraged you and savings CAN be made if you try.

Me? I'd be looking for savings in the bigger consuming items - even dumping a PC for a laptop can save you much more money than swapping from filament to CFL/LED lighting. Charging batteries using E7 and feeding it back to (say) your TV during full-rate times can HALF your energy costs. Those are but two ideas that are feasible and 'efficient' - especially in terms of energy/money saved.
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Re: working out small energy savings

Post by big-all »

funny enough even using the same led using tool batteries at slightly under voltage even allowing for charging cost works out at around 50% savings over using on the mains with electronics

i would have thought a heat pump would be your number 1 priority with a a 2 to 3to1 ratio similar to gas and if you water wheel to power it its going to be close to free :lol:
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Re: working out small energy savings

Post by Someone-Else »

I can see both sides of the coin.

big-all, you are right with your calculations and savings. kellys_eye you are also right with your obsevations,

I would have to say that perhaps it would have been better to say it is up to each individual to work out how much will they save. Since in our household the same lights are never on for 10 hours / day. (even at week ends)

I am not saying its not possible to save money by changing to LED's I am saying its not as much as its being made out to be. Then again, there is always the white meter scenario.

(Years ago white meters were installed to supply electricity off peak at a cheaper rate for storage heaters, thousands and thousands of people then had them installed, so the electricity suppliers jacked the prices up with the idea of making more money, trouble was, it backfired, people got rid of white meters and went to gas) my point being if everyone changes to LEDs, the demand will go down so the prices will go up more.
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Re: working out small energy savings

Post by kellys_eye »

Prices rises are a given - in a society where 'dividends are king' there is no way any (utility) power generator is going to allow their profits to fall so any savings you make will ALWAYS be offset by price rises to cover their 'losses'.

It's a scam - and then some. We're approaching a tipping point in that home-generation is going to take off one way or another - even now it's cheaper to use your own genny than rely on grid power! Especially if it's converted to run off gas! Only continual increases in petrol (diesel) costs can stop home generation happening but, mark my words on this, there will shortly be legislation to prevent people using home gennies..... or excessive taxation to make it unpalatable.

I always wonder what it would take to get politicians to realise that the world revolves around CHEAP energy - consumerism will die without it. I live in a small enough community that a collective effort to install a diesel genny would make sound financial sense but I'm also looking into harnessing the hydro power from our villages private water scheme - and extension to the plans I have for harvesting my own power from MY private water source.

Those eco-loons have a lot to answer for - tw@ts :angryfire:
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Re: working out small energy savings

Post by big-all »

to be honest i embraced low energy bulbs when they where around £13 each 30 years ago £13 was around £40-50 in todays equivilant i used to get one bulb every other month or so took a year to cover most used areas
i started on leds about 3 or 4 years ago with the horrible corn bulbs :lol:
the prices have come right down with the normal style bulbs now from the uk and about half the price off china 2 years ago
tool station started with £19 for one6.3w bulb now down to £13 and about twice the price off other sources

i have gradually lowered my consumption and costs over the last 10 years or so indeed i have gone from around £42 a month to £52 a month for both gas and electric over 10 years that a great feat considering price hikes
non off the savings are from gas as the boiler is around 35 years old :lol:
modern electronics save around 30% on running costs every year or so assuming no increase in performance [21"cathode ray to 21" flat screen] some reductions come from are from swapping deals between power supplier often swapping every year or 2
in recent years moving from vhs videos to 2 freeveiw recorders mean i don't need 5 videos or tv videos to record a days content so the relevant machine are turned off at the mains[kitchen front room my bedroom and 2 in the main room]as i never watch tv in other than the main room i do have a tv in the shed but no machine attached
other savings are from unplugging or turning off things like the printer battery chargers router computer screen when not in use

any way the point i am making is when you do more than one change at the same time it will confuse the actual saving from from any one change but i am happy enough that led bulbs
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Re: working out small energy savings

Post by jg »

BA,
Do you find that that last type of bulb (the 10W bulb shaped ones) make your ceiling too dark as the bulb part is all facing down?

I need to get some to put inside the shade of some ceiling fans. I'm limited to about 12cm length with a screw type connector.
i've ordered a couple of different ones just to see what they look like.
I am not a pro.
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