# How much electricity am I going to use?

Discussion in 'Lighting Equipment' started by steve_gibbs|1, Jan 16, 2007.

1. ### steve_gibbs|1

I need the help of someone who paid more attention in physics...

I recently won a contract for a product catalog project. I will be using two 1000w tungstens by request
of another person involved in the project (I normally use strobes!). By my figurings, the lights will be on
for 10-12 hours per day, 6 days a week, for almost 6 months. Since it will be in my small studio, I am
worried that I will lose some significant money with the extra power consumption.
Anyone know HOW much power I will be using? I am trying to figure this out to come to a final
margin on the whole project........

Any input is helpful...thanks

2. ### Matt Laur

IANAPOAEL (I am not a physicist or an electrical engineer), but, it just so happens that your power company thinks in terms of "kilowatt hours" when billing you. Essentially, your 1000-watt lamp, running for an hour, is burning 1kwh. Two of them, 2kwh.

6 months x 6 days/week = roughly 174 days.

174 days x avg. of 11 hours per day = 1914 hours

with two lamps, that's 1914 x 2 = 3828 kilowatt hours.

Round up, of course: you're generating heat that you may need more AC to remove from the room. You'll go through lamps/parts. You'll be running computers, fans, who knows what else. Call it 5000 kilowatt hours. You're halfway to a megawatt hour!

Most utilities adjust your rate a bit based on how much you use. You can read an interesting page here for some sense of this - but the average cost per kwh in the US last March was \$0.0986. Let's just call that ten cents, because of fuel, inflation, taxes, etc.

5000 kwh at \$0.10 is \$500. Now, I don't know about you, but with a sustained shooting schedule like what you're describing, working under 2,000 watts of hot lights, I'm likely to go through at least \$500 worth of beer in six months, too. Overhead! It's not just for retailers. Hope this helps.

3. ### don_davis|2

Hi Steve, I never took phisics but this is simple math. 1,000 watts for one hour is a killowatt hour so if you pay ten cents per killowatt hour as I do each light costs ten cents per hour to run. To find the true cost per killowatt take one bill and devide the total cost by the number of Killowatts paid for. Many utillity comanies only talk about the cost to produce not the cost to deliver a killowatt. And yes the cost will astronomical compaired to strobs. Good luck D.D.

4. ### Jeremy Stein

2 x 1kw x 10hrs/day x 6 days/week x 6 months x 30 days/month = 21,600 kilowatt-hours. At \$0.10/kw-hr, this would come to \$2160 for the electric power alone. You probably will have to buy replacement light bulbs more than once during the six months. Note also that the bulb's color temperature may well change over the life of the bulb.

Strobes are likely to be much better for your purposes...

5. ### ellis_vener_photography

1000 watts x 2 x 11 x 6 x 30 x 6 = nearly 24m illion watts /1000 = 24,000 kilowatts

You'll also make the room you are working in very warm unless it has really good
ventilation. Over 90% of the electricity used in tungsten lights is turned into heat not light.

And if you are shooting with a digital camera tungsten is not an ideal light source as it is
heavily biased towards the red end of the spectrum (source: http://www.betterlight.com/
pdf/whitePaper/wp_color_accurate_photo.pdf )

What is their objection to electronic flash?

6. ### Jeremy Stein

My bad - the correct calculation is 2kw x 10 hrs/day x 6 days/week x 26 weeks = 3120 kilowatt-hours. That would be about \$312 at 10 cents/kw-h.

7. ### Jochen

2x11x6x25=3300kWh + additional use of your air condition during summer! - The lights should heat as well as a pretty decent hairdryer. Something between 50-75% of their Wattage will be pure heat. I can't handle the corresponding math but I'd guess your crappy air will draw more than 150% of that to compensate for it, but maybe you can stand that. With really extremely crappy air on I'd fear 10000kWh. Otherwise ad 3% for the modest luxury of a fan to the 3300kWh.

8. ### don_davis|2

Hi, An apendum to my previous post. Matt who was posting at the time I was writting is correct on the probable total consumption except for the facecious coment about the beer, that low? There is an interesting device available, a"Kill-O-Watt meter",that will give you the result you want and much other information ref your hydro use without any math. D.D.

9. ### bloosqr

all of it will turn into heat even the "light" part and while the room/house ambiently radiate
some of that away .. you should actually take the number you are getting (roughly \$500) and
add to that how much it will cost to run your AC to draw that much heat out of your room.

10. ### steve_gibbs|1

Thanks so far. I really thought it was more complicated than just "1000w = 1kwh usage"
though. Isn't there any resistance factors here?

The reason I can't use my own strobes is just stupid really. The company's CEO's son
claims to be a photographer. They originally gave him the contract. He screwed it up, and
lost the company a mass amount of money. They hired me with the stipulation that he be
involved, and for some strange reason.....he insists on using hot lights. (wysiwyg for
beginners, I guess). I considered not bidding on the job because of this problem.
Nepitism sucks when your not in the family!!!!

As far as the heat, it's not really an issue. My studio is in a very unique building that has
massive exhaust fans in the roof. It used to be an OLD, old paint house for farm
equipment.

And yes, the beer costs have already been factored into the job. Does St. Pauli Girl give a
quantity discount?

11. ### alan c brockman

I'm surprised that nobody has pointed out that he should be expecting a knock on the door from the police. They monitor power usage for abnormally high useage, or changes in usage patterns to help find people running hydroponic marijuana operations. He'll look like he's running an indoor farm.

12. ### steve_gibbs|1

Alan, that's really odd you said that. I had no idea about electric companies monitoring
usage for stuff like that BUT.....the job is for a hydroponic supply catalog.

13. ### Matt Laur

About changes in use (relative to law enforcement involvement): I've got a good friend who's a local county detective. 2kw of lamps running for 10-12 hours a day isn't anywhere CLOSE to what they're usually looking for. People who have three or four serious computers humming and a couple of TVs running (you know who you are!) or a couple of floorboard heaters aren't going to look any different. If they think they've got a really unusual pattern in the metering, they'll sometimes check from the outside of the house from the street (or, believe it or not, by helicopter) using thermal imaging equipment.

They're not, apparently, too worried about the size of an operation what would use 2kw for half of the day - much bigger fish to fry. On a funny similar note, I was running around a game preserve, D200 in hand (rather than a shotgun, rats) following a guide who works dogs on gamebirds in those fields. He showed me a clearing within a strip of woods where he'd recently discovered about 1-acre pot field, complete with plastic buckets full of fertalizer bags, and a baggie full of cash with a note on it from one "farmer" to his apparent partner about needing to go to Home Depot for some more. This was on private property... the guys just snuck in, looked for an isolated spot, and set up shop. Obviously the landowner was beside himself (since it could easily look like his operation). In came the sherrifs, who apparently said it was one of the smaller patches they'd dealt with that week.

And here we are, all trying to make a couple of bucks selling pixels. It's a good thing we haven't turned all of our creative energies to evil, huh? I mean, other than my mediocre dog pictures, for which I should indeed have to pay some sort of fine.

14. ### calebcondit

you're going to be limited by using tungstens and it's going to make for some really long exposures if you need f16 and will make for some pretty unpleasant working conditions. Its great that you're taking this, but if he messed it up before, if he has to be involved, it shouldn't be deciding how YOU light this. It's going to definitely cost more moneywise. I would say go with the other people's figures and add the extra costs to your invoice. Present this to your client carefully, but you shouldn't pay for their family's errors.

15. ### tom_jenner|1

"They hired me with the stipulation that he be involved"

I'm sorry Steve.

The cops and electrical company could care less about a 2KW addition. 6-10KW in a house, maybe. If it's in a commercial building such things can be expected.

(I speak from personal experience from distant past youthful indiscretions. Now a days aeroponics are for galena tomatoes)

16. ### stephen hazelton

I've heard of high electrical usage tipping police off. But I don't know that they routinely monitor that, either. Seems like when I read about it way back when, there were also questions of whether that justified a search warrant or not.

I would check into bulb cost. I remember my mom had old hotlamps for her 8mm movie camera, and those bulbs had pretty short lifespan- it should say on the bulb or the package, though.

17. ### gene_e._mccluney

I gotta tell you, coming from my 30 years of activity in Commercial Photography, if you are
worried about the cost of running your lights for your shooting, then you are waaay off in
your pricing of this job. Any Commercial Photography job should have enough profit
margin built in to take into account all of the overhead expenses for the production of the
job and a nice profit for the photographer. You do a great dis-service to the photography
community by pricing your work so low as to not cover all your expenses, as well as a fair
profit.

McCluney Photo

18. ### kelly_flanigan|1

Gene; I think we all underprice stuff when we start out! We might use our folks houses, electricity, cars! Then when were on our own the repair bills, rent and utility bills help change our ways!

19. ### ellis_vener_photography

They hired me with the stipulation that he be involved, and for some strange reason.....he insists on using hot lights.
Fine. Go to the company's president and say "Here is the deal: your son is here to learn and assist me as I need it and not to tell me how to do my job which is to make your company look good and help you sell more product. Doing things the way your son is telling me to work will cost you more money and more time." You ofcourse will have to figure out the diplomatic way to phrase this message. If the son still objects to using flash, sit him down with those BetterLight PDF's I posted the link to and have him read them.

20. ### savagesax

Well they want you to teach the kid how to shoot! It's that simple. I'd do the photo shoot my way only, using strobes, foamcore, barn doors, defusers, whatever it takes to give the client GREAT images. As you know tungsten is not the best light for product shoots. Ever try getting nice even white light on every shot with tungsten? The temp changes all of the time. Plan on some Photoshop work at an added cost to your client.

21. ### kelly_flanigan|1

If any of you folks venture into a movie set and whine about tungstens, you are going get labeled as abit of goofball, ones that has little experience, one that that is biased, one that might use a flash and screw up a shoot.<BR><BR>Tungstens have been used for a century in films and still shots. You dont have to have them on all the time. There are tools called variacs and series parallel switches that are used professionally to dim lights, reduce the heat, and radically extend the lamps life. In movies a 1kw lamp is called a Baby, a 2kw a Junior, a 5kw a Senior, a 10Kw a Brute, Tenor; etc, a 200watt is a Midget; a 100w a Pepper. The words vary abit with the crews, a 1000watt lamp really is not a big lamp.<BR><BR>A CYV 1kw lamp bipin Mogul bulb costs about 50 bucks and last 200 hours. Thus with two bulbs on for 200 hours one spends 100 bucks for expendables; ie 2 bulbs. One also spends 400 kwhr ; or 40 bucks at 10 cents/kwhr. Thus folks worrying about the electricity here on this thread Are worrying about 40 bucks, and ignoring the 100 bucks, totally totally bizzare!<br><br>Sometimes folks want to use tungstens because there are great adjustable rolling stands, with filters, tilts, gobs of barn doors, Bazookas, scrims, trapeze, Diffusers, snoots,. They also may want to shoot movie film, shoot with an old scan back that requires a long exposure. They also may have had a bad experience with strobes with terrible UV output, or have a rare art piece that the owner doesnt want shot with strobes.<BR><BR>A balance of tungstens for modeling and shooting and strobes for some shooting is what one should do, instead of a holy war attacking the other system. The product can be a weird material that has a UV response to strobes, OR stuff that doesnt like heat. Keep an open mind and dont buy into the dogma by amateurs to always use strobes or tungstens. Keeping the tungstens on all that time sounds abit dumb

22. ### gene_e._mccluney

I use strobe for film and for SLR format digital, and for my Scanning Back I use big 2kw
fresnels, and others. The heat build-up is quite noticable for the large tungsten lights.
However, I have never considered the added cost of electricity, and will not start now, as I
have structured my prices to cover these overhead expenses. It is common practice to
switch the lights off when taking breaks, lunch, etc., so it is not a continuous expense
unless you are shooting continuously. You need to factor in the replacement cost of the
bulbs into your overall pricing plan, as they do and will fail, although I have found that the
largest bulbs have an amazingly long life. They are quite costly to replace.

McCluney Photo

23. ### steve_gibbs|1

This is a pretty simple side-project & don't want to spend much money because the
competing bids were low to begin with. my studio operates 6 days a week, with several
projects running at any one time. Bulbs are not the only other overhead to consider. If you
want to get technical:: Heating bills increase more than \$100 just from MORE people
entering & exiting the building (its 9 degrees here), water bills become noticeable when 30
more people are using the restrooms, more coffee is comsumed in the break room, the
music is on more, etc. It would be nice to simplify things by saying that the power bill is
insignificant just because I have to buy some bulbs, but in reality......it all adds up. If you
understand profits, you know that ALL costs must be factored in to find a true number!

24. ### steve_gibbs|1

"Any Commercial Photography job should have enough profit margin built in to take into
account all of the overhead expenses for the production of the job and a nice profit for the
photographer."

So Gene; in 30 years, you have learned to EAT the small expenses rather than factor them
in? Doesn't make sense. Seems like a pretty pretentious comment, and pretty moot to the
question. I have people to pay, a family to feed and a ski habit to please. My profit
margins are fine...I like exact figures.

1111