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Re: working out small energy savings

Posted: Wed Jan 02, 2013 10:58 pm
by big-all
there is minimum light going up towards the ceiling as the total illuminated area is virtually flat although some bounces off the glass and travels backwards but will be in the region off perhaps 5%

corn type bulbs will light similar to a normal bulb spread wise ... 2ec1e80aea

Re: working out small energy savings

Posted: Sat Jan 05, 2013 10:08 am
by jg
I've ordered a couple of corn type SMD ones and one of those half globe type ones.
Will post some reviews once I get them in about a month :)

Re: working out small energy savings

Posted: Sat Jan 05, 2013 3:17 pm
by Inky Pete
Surely it's better to simply switch off lights which are not in use?

I only need light at all in whatever room I'm occupying at the time, say 100W maximum at any one time. I'm only in the house and awake for maybe 4 hours per day on average, and in the summer it's light until virtually bedtime so only really need that level of artificial lighting for at most 6 months of the year. On top of that, I'm probably away a total for around 4 weeks during the winter months, so now only need lighting for 5 months of the year.

So my typical annual consumption would be 100 x 4 x 150days = 60kWh. At 15p per kWh that's only £9 - not much scope for energy efficient bulbs to pay for themselves there!

Re: working out small energy savings

Posted: Sat Jan 05, 2013 5:32 pm
by big-all
if you live in a terraced house or with trees everywhere like i do
i dont have to sit in poor light all day worrying about the bill i can leave the light on
as an aside
i found quite a large saving from a surprising source off 70w-------

---central heating water pump on step 3=140w step1=70w

Re: working out small energy savings

Posted: Sat Jul 05, 2014 12:13 pm
by bmbtimberwindows
Small energy savings leads to bright glowy future.

Re: working out small energy savings

Posted: Thu Aug 06, 2015 4:56 pm
by John_75
I replaced my old radiators with trench heaters that use natural convection and can notice changes in my heating bills.

working out small energy savings

Posted: Thu Jul 09, 2020 12:20 am
by ericmark
I have been changing bulbs to LED, however not as straight forwards as it seems. With a house using gas or oil for heating, since gas and oil is cheaper than electric, the use of LED bulbs saves money, however that does not mean it saves energy, the thing to remember is in the main we don't want the room at same temperature throughout the day, with a living room for example we may want it at 18°C during the day but 22°C in the evening, then drop again over night.

Air takes time to heat up and cool down, but inferred is near instant. So in winter having a tungsten bulb means due to inferred from it on switching on lights room feels warmer, the thermometer will likely show no change as sensor is guarded from inferred heat, but room feels warmer, even if air temperature has not changed.

So when changing to LED or fluorescent you also need to change the way the heating is controlled, so the wax TRV head is replaced with a programmable electronic head, so you can let the room stay cooler during the day than in the evening.

The LED and fluorescent use less power as said, this means you get problems with electronic switches both on/off and dimmer types, in the main in the UK we only have permanent line and switched line at the switch, we don't have a neutral, so to work a small amount of current has to flow through the electronic switch, with tungsten this is not enough to light the bulb, but with LED and fluorescent it can cause bulb to flash when switched off, even just having the switched and permanent line wires next to each other can have a capacitive link high enough to cause lights to flash specially two way lights, so most bulbs in UK have a small leak through resistor to stop this flash, but it in the main means bulbs need to be over 5 watt. So a chandelier with 5 x 2.8W G9 bulbs is often a problem.

As the name implies the LED has a diode in it, but not only the one emitting light, it also has a full wave rectifier in them to turn AC to DC, as long as it is full wave there is no problem, but should any of the diodes fail, then with half way rectified supply it causes DC to flow in the supply wires, this DC can saturate the iron core of some RCD's and cause them to be desensitised, so any type AC RCD's should be changed to type A RCD when fitting energy saving lights, personally I think the risk is very low, and I still used type AC but when testing the RCD all lights should be switched on, so if the RCD is being desensitised you know there is a problem.

A raw LED will give around 100 to 120 lumen per watt, but in a package as a bulb, this is often much lower, and can drop to 60 lumen per watt, and LED for decoration can be as low as 25 lumen per watt, the EU law says that all bulbs must show lumen output, unless for decoration, so if there is no lumen output shown, then likely the lumen per watt is very low.

Fluorescent and LED lights have a problem with strobe effect, it depends how they are controlled, the electronic ballast with fluorescent and the pulse width modulated control with LED does reduce the effect, only insects can see the flashes, but it can give some people headaches, also there is a flicker caused by interaction with electronic switches, and often one needs to change bulbs to stop it, one method is with a chandelier to use not tungsten bulb.

Often you need to change or fit a chandelier to get enough light, the 100 watt tungsten bulb is about 1600 lumen, and being so bright the light bounces off white surfaces lighting the whole room, a 15 watt LED is around 1125 lumen so clearly less light, so in my living room the 100 watt tungsten has been replaced with 8 x 6W LED bulbs with the base at bottom so the light is reflected off the ceiling giving a good spread of light so around 3600 lumen, the 100 watt tungsten was not enough light, and a 15 watt LED was like a tocH candle.

Once the light fittings are changed so you can use more bulbs yes the LED works well, but this needs to be factored in, dining room I have 5 x 6 watt = 2250 lumen, yet in my old house I swapped the 65 watt fluorescent around 5600 lumen for a 24 watt LED tube at 2400 lumen, the problem with the fluorescent was to get the length so spread of light, you also had to use a fixed output, latter 5 foot tubes were 58 watt but you simply could not buy a 25 watt 5 foot tube, they were not made. Fluorescent and LED are around same lumen per watt, with an electronic ballast a fluorescent tube is around 95 lumen per watt, however the folded fluorescent made to replace a bulb was really a failure. But only reason why an LED replacement for a fluorescent tube uses less energy is it gives out less light. My son replaced the LED tube with 9 GU10 lamps and actually uses more power. It is quite common for the small spot lights to need more power than the standard bulb, it seems lumen is not the whole story.

Old house living room started with 2 x 100 watt tungsten, and it was changed using a chandelier to 6 x 40 or 60 watt, which went to 6 x 11 watt folded fluorescent that went to 10 x 8 watt golf bulb florescent that went to 10 x 3 watt and then 10 x 5 watt LED. The folded fluorescent never really worked, so start with 3200 lumen and end up with 4000 lumen but to do that needed 5 bulb chandeliers, also the simple thermostat had to be changed to a programmable thermostat. So went from 200 watt to 50 watt, that is not what all the conversion charts say, they tell me 30 watt LED = 200 watt tungsten, but the 3 watt LED bulbs were not bright enough and had to be replaced with 5 watt.

The main reason for LED was before I would change a bulb some where in the house around every two weeks, with LED I can list the failures over 8 years, 1 x 24W LED replacement for fluorescent tube, 2 x G9 LED, 3 x G5.3 LED's but they were really toys, and that is main advantage your not changing them all the time, however back in early 90's I fitted a battery backed 18W fluorescent above the stairs, only renewed the tube once in all that time, and it is likely the most used light in the house, and was second hand to start with. There are accounts of incandescent bulbs lasting over 100 years never switched off, however they were before tungsten and now only show a red glow.

But saving energy, or cost, considering price of bulbs and chandeliers required to use them, plus cost of programmable thermostats and swapping the type of RCD, plus the failures when too small or flash, and fitting load capacitors, swapping dimmer switches all added together, no they don't safe energy or money, they just save the hassle of changing bulbs, and since you can't buy a pearl 100 Watt tungsten bulb any more there is really not option. You should not use dimmer switches with quartz bulbs, and many of the tungsten bulbs today have quartz inside glass, have to be put inside glass one because of dangerous rays and two risk of fire if the fail with ionisation so really no option.

But really it breaches the trades description calling them energy saving bulbs, they only save energy when you don't want the heat, and we don't use lights that much in summer. However if you have silly spot lights 9 x 50W is a lot of heat, and in a kitchen you want to reduce the heat as much as you can, so LED bulbs and induction hobs and well insulated electric ovens really reduce to total heat compared with gas oven and hob and tungsten lights, so in the kitchen either fluorescent or LED, but that is the odd room out.

I know when we went to induction hob the kitchen temperature really dropped, our house and father-in-laws house were the same, next door but one, his kitchen was so hot and humid compared with ours, mainly because he used gas to cook and we used electric. Electric likely costs more, but gas likely used at least twice the energy to electric.