Why turning off the lights is a waste of your time

[Zero999]

One of the members here works at a wind tunnel that uses 4MW at full output, that is just one facility using 0.01% of all of the power used on average in the UK.

32MW peak and managers worry about saving energy.

[Simon]

so nearly 1% of average consumption. Yes but still other aspects of the business should be efficient. It's not like they would just run at 50% wind tunnel power because who cares. The small things matter too because we all do them. As I said we have maintained a flat consumption over 20 years with a growing population as things got more efficient. Now power consumption is going up and we have to start providing that power. there anly has to be a fractional shortage of power on the grid and standby plants are called on who will charge much higher rates.

[Simon]

So I just left the house to drop off some parcels.

As I've been rather inactive I cycled rather than drive, with the round trip of 2.6 miles this saved about 1kW that the car will not be recharging by tonight. As I am running BOINC and folding at home my PC is loaded to the hilt all the time and it was not worth turning it off, but the two 50W monitors did turn off once I left my desk, so 100W saved. I also turned off the room lights as I left, 15W worth. So for the 30 minutes I was out 57.5Wh was saved at a rate of 115W, now consider that out of a population of 70 million some 1000 other people are doing similar things at the same time, turning 10's of watts of things off for a short time while not needed, that would equate to 115kW less draw on the grid. In the UK that is equivalent to the power available to 50 homes or 150 people who now can use that power. We use on average 2kW per home or 660W per person precisely because there is a certain profile of power consumption. If lots of people are practicing the same thing on average it will make a difference - for better or worse. If on average our consumption increases to more than 660W per person on average then more supply has to be called in and prices rise as the energy market is a live auction system running on the demand for a 30 minute slot, every 30 minutes the price changes based on who is supplying and what type of generator they are. Most of these are prearranged the day before some are held on standby and we pay for them regardless of whether they are used or not.

[mcz]

One of the members here works at a wind tunnel that uses 4MW at full output, that is just one facility using 0.01% of all of the power used on average in the UK.

32MW peak and managers worry about saving energy.

32MW for a wind tunnel? That's the rated power output of 10 decent size land based windmills. With a rotor diameter in the ballpark of 100 meters each. Does this thing fit an entire A380 or what?

Also I find it odd to discuss turning the lights off. Since you walk by the damn switch when leaving the room you might as well hit it. It does not take any additional time and I would assume most people have been properly educated about it as a child so they don't even have to think about it. But whatever, maybe some people need to burn some extra cash so they don't need to worry about inflation.

[Simon]

32MW for a wind tunnel? That's the rated power output of 10 decent size land based windmills. With a rotor diameter in the ballpark of 100 meters each. Does this thing fit an entire A380 or what?

look up fan laws........

[Alti]

Also I find it odd to discuss turning the lights off. Since you walk by the damn switch when leaving the room you might as well hit it.

I disagree, the discussion is an important one.
This is an activity everyone (8B of us?) is doing not questioning "what for".

"Hitting a damn switch" is an activity that eats up resources. If switch is in a convenient location when leaving the room, it might not be as convenient when you get back. What if you get back in half a minute? What if you come back with tea in one hand and plate with some cookies in the other? This switch had to be bought, installed and maintained you know. This does not come for free. From the fact you switch on/off the light every time you leave the room and then with both hands occupied turn light on with your forehead is odd, not the OP's question. Or you could do that in two rounds, first tea then cookies. Now please tell us what do you do with corridor lights once you turn the room light on? So you put the tea on the table and then you hit the switch and leave the room to hit the corridor lights off? Or do you run around in complte darkness? Your "when leaving the room you might as well hit it" we do that quite frequently but NONE of us does that every time. Attitudes span from 7/24 lights ON down to switching light OFF while blinking.

Of course you can have gazillion of switches in every room and corridor, on this and other side of the door, for left and right handed, short and tall, motion sensors and timers. This does not change the fact that this "light demand adjustment" eats up resources.  Training, wiring, maintenance, spilled tea, planning and inconvenience, disagreements within family and tenants.

Is this dance justified? My answer is: I do not know. What I know that at some efficacy/kWh_price fraction this is irrational as this leads to more losses than benefits (OP's point).

[james_s]

“Nothing will be lost since power generation is adjusted according to consumption.”

That’s simply not true in practice. If a bulb is on or off in my home the generation quota from the plant will be the same. Sure if our collective behavior of thousands of people creates enough reduction in demand for the station to reduce the quota power will be saved assuming those people have behavior that is consistent. In reality though if I turn off the light, the power being distributed in the moment just goes to ground and since people are unpredictable even as a group, the quota for a sector never changes.

It's all averaged out. You are looking at this the wrong way, it is not just your roommate turning off that light, it's millions of other people out there turning off lights, while other people are turning on lights. You may not think it matters if you take a rock from a national park for example, it's just a rock, there are millions of rocks, so what are you really saving by not taking one? Well consider if every visitor to the park took a rock.

Personally I turn off lights I'm not using because I feel more relaxed in subdued lighting. I doubt I would really notice much difference in my bill if I left them all on but it adds up over time.

[jonovid]

in the age of energy efficient lighting, hitting light switch's everywhere is symbolic or visual signaling I have family members that will do this.
but its the big domestic appliances that matter. as walking into dark rooms is a little unpleasant. real estate agents understand this selling point.
on the flip side some home builders will pix up a plastic bag, but dump a trailer load if to avoid rubbish tip fees.
if it looks biodegradable.

[SiliconWizard]

I've not read quite all, but... No, the energy won't be lost if you don't use it here. So yes, switching off the lights will save energy.
Now is that worth the trouble? As many have probably said, if all your lighting is LED-based, the power consumption of your lighting in the whole house, even if you left them all on 24/7, would be pretty negligible compared to all the rest.

So yeah, it's more a symbolic gesture than anything else. But in that, it's no different from a lot of what we currently do for "saving the planet".
If anyone feels better doing it, so be it. Although, if it becomes borderline obsessive, it may in the end do more harm to them than good. But that's for his doctor to say, not us. =)

[John B]

Well..... use motion-controlled switches instead. Happy roommate, happy you.

For an electronics forum, I'm surprised only 1 person suggested this. I make my own lighting using 5V DC powered motion sensors paired to a micro, but you could even use a 555.

It doesn't have to be a permanent installation, and it's all powered through offline power supplies, so no issues with setting it up a rental yourself, and removing it when you leave.

[BILLPOD]

Good Morning Simon, they put motion sensing switches in the men's room where I used to work.  Then the BIG boss went into a stall to take a dump and after a couple minutes the motion switches shut the lights out and he had to guess when his bum was wiped sufficiently.  The next day the motion switches were gone.
 in the office toilets for them. I just could not believe it when I took the bulbs down and read on them that they were 100W. So 400Wh were running about 9 hours a day or 3.6kWh was being used a day for lights that were actually of used for about 1 hour a day. They then had all the lights changed to LED and  motion sensor lights were put in.

[Simon]

Good Morning Simon, they put motion sensing switches in the men's room where I used to work.  Then the BIG boss went into a stall to take a dump and after a couple minutes the motion switches shut the lights out and he had to guess when his bum was wiped sufficiently.  The next day the motion switches were gone.
 in the office toilets for them. I just could not believe it when I took the bulbs down and read on them that they were 100W. So 400Wh were running about 9 hours a day or 3.6kWh was being used a day for lights that were actually of used for about 1 hour a day. They then had all the lights changed to LED and  motion sensor lights were put in.

Yes, motion lights with too short a time out are pointless, and they did that too. I mean it should be 10 minutes not 2.

[John B]

Toilet stalls are also a problem for motion sensors as it creates a lot of dark/shadowed areas for the sensor(s) with the high stall walls. Not to mention being a commercial/work penny pinching environment, probably only 1 senor gets installed 

[HobGoblyn]

I haven't done the precise calculations, so could be wrong. But when I hear, people say, they collected a bag of recycling, be it paper/plastic and so on. Then DROVE IT to their local recycling centre, and recycled it.

The root issue in your example is the production of that waste to begin with. Why was it needed? If it was needed, then why it needs to go to waste? Chances are, 95% of it was completely unnecessary to begin with (typical example being single-use throwaway fashion, which I thought was a small problem, but then saw the numbers somewhere and it's really huge, like a well-organized industrial process designed to produce unbelievable amounts of waste).

When I was a kid (60/70s) I don’t recall anyone complaining that veg or meat wasn’t wrapped in plastic, confectionery wrapping was always made of paper etc.

No consumer asked for it, now we have to spend the extra time sorting it into the right coloured bins (and occasionally find out months later that it all ended up in the same place anyway)

The fashion trade as a whole is messed up, but it seems to go into other areas.  If someone famous was seen out in the same dress twice, it would probably make headline news in the tabloids.

Most people here enjoy fixing things. Before I took up this hobby, about 7 years ago my Zanussi Dryer packed up.

I contacted Zanussi, will cost more to fix than a new machine.

Went to a white goods forum, someone said it’s the main board, you can’t fix them and it’s something like £250 for a new one.

I thought it was worth a go trying to fix it, all I did was run my cheap fixed temperature soldering iron over most of the joints.  7 years later it’s still working 100% fine and as my wife is a mobile hairdresser, gets used multiple times per week.


Mind you, if I called someone out to remove the board, take it to their lab and see if they could fix it etc, it probably would be cheaper to buy a new machine.


It’s a strange world we live in, but it’s not one that most consumers asked for.

[CatalinaWOW]

There are a variety of arguments here.  On the simplest, the physics says that turning off lights and other energy conserving tactics works.  More complicated, is the savings worth it based on comfort, happiness etc.

But the real zinger is that if there are going to be 16 billion of us living here in a few years, comfort and happiness will not be important.  You can only split the pie so many ways.  The real optimization would be to figure out how many people it takes to support an advanced technology civilization in comfort and how do we turn off the babies to get to that number.

[not1xor1]

There is a known and well studied negative effect of all those energy saving measures, but it depends on the biased human nature.
Most people using LED lighting, electric cars, etc. unknowingly leave them on more and more often or make more road trips and at higher speed... «who cares we are saving energy» !?!?

Switching off lights makes sense if you do not have to go back into that room in a couple of minutes. But I've seen youngster keeping TVs, PCs, lights always on and local politicians adding more and more street lights because they are energy savings so who matters or those electric cars with ludicrous power, hundredths of KW just for making a couple of km from home to the shopping mall... and all those (typical US) homes lit like huge Christmas trees.

But we all have to make our best efforts to reduce energy waste. Switch off unused lights as soon as possible. If possible switch on small power light spots where needed rather than a more powerful light in the middle of the room, and so on.

[mcz]

Also I find it odd to discuss turning the lights off. Since you walk by the damn switch when leaving the room you might as well hit it.

I disagree, the discussion is an important one.
This is an activity everyone (8B of us?) is doing not questioning "what for".

"Hitting a damn switch" is an activity that eats up resources. If switch is in a convenient location when leaving the room, it might not be as convenient when you get back. What if you get back in half a minute? What if you come back with tea in one hand and plate with some cookies in the other? This switch had to be bought, installed and maintained you know. This does not come for free. From the fact you switch on/off the light every time you leave the room and then with both hands occupied turn light on with your forehead is odd, not the OP's question. Or you could do that in two rounds, first tea then cookies. Now please tell us what do you do with corridor lights once you turn the room light on? So you put the tea on the table and then you hit the switch and leave the room to hit the corridor lights off? Or do you run around in complte darkness? Your "when leaving the room you might as well hit it" we do that quite frequently but NONE of us does that every time. Attitudes span from 7/24 lights ON down to switching light OFF while blinking.

Of course you can have gazillion of switches in every room and corridor, on this and other side of the door, for left and right handed, short and tall, motion sensors and timers. This does not change the fact that this "light demand adjustment" eats up resources.  Training, wiring, maintenance, spilled tea, planning and inconvenience, disagreements within family and tenants.

Is this dance justified? My answer is: I do not know. What I know that at some efficacy/kWh_price fraction this is irrational as this leads to more losses than benefits (OP's point).

If I leave the room and I do not use it anymore (aka I do not plan on coming back) I turn the lights off. The chances of me returning because I forgot something might be high but I very likely won't do that with a cup of tea.
On the other hand you might not turn the light off and go do something else for just a short while (oh so you thought) when suddenly a family member or friend calls and you gotta leave. Now you left the lights on but want to leave the house so you run all the way back upstairs and flip the switch. Meh.
Yes, you can discuss this all the time but in the end beeing mindful about what the heck I am doing right now and hitting a switch does not cost me any money while electricity does. We all forget it quite frequently but the general intention is still there and it works most of the time.

A 10W LED bulb costs me about 7.2 cents a day. Assuming 8 hours a day usage of a room that's 4.8 cents gone for nothing. So installing a light switch for 20 bucks total (assuming it is done right away) actually pays in about 420 days (nice).
Over a lifetime of 20 years it is 350 bucks saved. And even it it didn't, having a 24/7 light is hugely annoying.

I think electricity as well as central heat lost the appreciation it deserves for bringing us so much comfort in our daily lives. Letting it go to waste just because of my own lazyness is not something I intend to do.

[james_s]

Good Morning Simon, they put motion sensing switches in the men's room where I used to work.  Then the BIG boss went into a stall to take a dump and after a couple minutes the motion switches shut the lights out and he had to guess when his bum was wiped sufficiently.  The next day the motion switches were gone.
 in the office toilets for them. I just could not believe it when I took the bulbs down and read on them that they were 100W. So 400Wh were running about 9 hours a day or 3.6kWh was being used a day for lights that were actually of used for about 1 hour a day. They then had all the lights changed to LED and  motion sensor lights were put in.

I worked at a place that had that too, it was the dumbest thing ever. They installed the sensors where there were originally switches, next to the door and facing the opposite wall rather than out into the room. Multiple times I had the lights shut off while I was in a stall and had to use the flashlight on my phone.

[coppercone2]

in the USA: 5.6 billion bulbs, times 10 watts (conservative), 56 (GW) billion watts in use.

The quotes are 2% of total use. 2% of anything for national things is very big.

[Siwastaja]

The quality of life argument is interesting.

The best thing that's happened during last decade is the phase-out of CFLs. Good riddance.

Take an example of a bathroom or storage room bulb. Low duty cycle of use, short on-period in just minutes.

Say, it's originally a 60W incandescent bulb. Light switch placed at convenient location, it's no big deal to turn lights on and off.

Now replaced with a 11W CFL, it's simply too dim for a minute or two, especially if the room is cold. So while the energy efficiency seemingly goes up, the quality of life is devastated below what is acceptable; it's simply too dark. Now this issue is sidestepped by keeping that light always on. The end result is hugely increased energy consumption compared to the original incandescent bulb (because the duty cycle of use was so low that average power with the incandescent was small).

Now enter the LED. Not only the power consumption drops to 6W, meaning keeping the light on all the time (by accident, or on purpose) has significantly smaller impact, but the user can also go back in the old habit of turning the light on and off as they enter and exit the room, basically dropping the energy consumption to zero.

[Bicurico]

As I mentioned in my previous post, quality of life is a huge argument.

For private homes, leaving light switched on can have many subjective reasons, which are all rationally wrong, but contribute to well being none the less.

If you have pets like dogs or cats for instance, it is not uncommon to leave a light on when you are not at home, so that the pet can be more comfortable - at least in the human's opinion.

If you are at night doing stuff (cleaning, getting a snack, watching TV and going to toilet), it just is more convenient and comfortable to have lights switched on in the room and corridors. It makes the ambient more cosy and secure.

Of course you could move in the house switching lights on and off as you move around. But is that really worth it? In the extreme you could just use a flashlight!

And if I pay for my electricity, I don't care if the power I consume requires a turbine to rotate faster or not. I am paying for it.

All this environmental issues are based on misconceptions. The problem is not the consumer who uses more or less power, fuel or whatever. The root of all environmental issues is the fact that there are too many humans on the planet. We should see politicians start thinking of ways to reduce the birth rate, especially in those regions where it is too high.

And we should do something about interest rates, resulting need for economic growth and the whole Pontzi scheme that is social security and pensions.

These are in my opinion the real reasons why we have environmental problems. Switching the light off every time you leave a room will not make any difference at all when all African, Chinese and Indian people (no offense) have access to a house, heating, fridge, car, etc. And why shouldn't they be entitled to the same luxury as us western people?

Regards,
Vitor

[not1xor1]

As I mentioned in my previous post, quality of life is a huge argument.

For private homes, leaving light switched on can have many subjective reasons, which are all rationally wrong, but contribute to well being none the less.

If you have pets like dogs or cats for instance, it is not uncommon to leave a light on when you are not at home, so that the pet can be more comfortable - at least in the human's opinion.

pets usually are more comfortable with dim lights... cats need almost no light
but go on and keep as many lights on as you like... today... and barely survive in the dark tomorrow

[Zero999]

The best thing that's happened during last decade is the phase-out of CFLs. Good riddance.

I've found CFL to be more reliable, than LED, in some applications, especially where it's hot and the lamp is left on for extended periods. CFLs is a bit more efficient, but not enough to outweigh the cost and environmental impact of having to replace LEDs, in places where I've found they're more prone to failure.

[Siwastaja]

Just use incandescent bulbs in hot environments. (And by hot, I don't mean +40degC ambient.)

Yes, I have seen two failed LED bulbs in my life and neither were originally mine so I don't know. One was in sauna, regularly seeing temperatures around 70degC and high humidity. I replaced this with an incandescent bulb. Massive amount of energy is spent heating up the sauna anyway. The loss of the light bulb only contributes to that.

Another one, I have no idea why it failed. So one real failure. Possibly; maybe this bulb was abused as well.

I have seen many CFLs that failed early. Many are dim beyond acceptable after mere 5000h.

The root causes for early LED and CFL failures are very similar, both contain electronics subject to high temperatures.

CFL lasting longer than LED is definitely false generalization which might be true as a single personal observation thanks to small enough sample size - i.e., bad luck. My observation is the opposite. But my sample size is very small (maybe just N=10?) thanks to the fact that every LED bulb I have ever bought still works. Good luck - maybe.

[mcz]

As I mentioned in my previous post, quality of life is a huge argument.

For private homes, leaving light switched on can have many subjective reasons, which are all rationally wrong, but contribute to well being none the less.

If you have pets like dogs or cats for instance, it is not uncommon to leave a light on when you are not at home, so that the pet can be more comfortable - at least in the human's opinion.

If you are at night doing stuff (cleaning, getting a snack, watching TV and going to toilet), it just is more convenient and comfortable to have lights switched on in the room and corridors. It makes the ambient more cosy and secure.

Of course you could move in the house switching lights on and off as you move around. But is that really worth it? In the extreme you could just use a flashlight!

And if I pay for my electricity, I don't care if the power I consume requires a turbine to rotate faster or not. I am paying for it.

[...]

If I have to get up at night I rather use my phone flashlight because it takes too long for my eyes to adjust if I turn the main lights on. Also I need to use the flashlight anyway because I don't want to turn on the bedroom lights and make my wife angry.
And I'm also not scared of the dark so if it's a nice moonshine outside I don't turn on any lights.
On all other occasions I usually use/adjust the light to my needs. Some work requires additional lighting but while watching TV in the evening I like to turn the main lights off and just use a small lamp.

But my point is not related to our personal comfort but that leaving the light on for no reason apart from beeing too lazy to actuate a switch like OP suggested is just lazyness. And there is nothing about it that makes it special and edgy and cool.

And most importantly, the power turbines run at the same speed all the time. Most mechanical generators are of the synchronous type. Electrical power consumption varies the load (torque) that the generator poses but not the frequency (well, hopefully not!)