Power Measure/Rating? Cost?

[Bookmage]

Something I've been wondering for a while and been debating with friends and parents about, is how much power a computer uses. The ratings on power supplies are in hundreds of watts, 300w, 500w, and the like, but what exactly does that mean for the normal user. How is that 300w, 400w, measured? Is that per minute? hour? year? IS it constantly pulling 300w, 400w? Or does it fluctuate? How much of a dent does that put in my electric bill for an apartment? house? cardboard box? And exactly how much $ does my power saving LCD monitor save?

So if in your average family of 4, u have say, 4 computers from both ends of the spectrum. An aging Pentium 2 on a measly 200w PSU for the youngest and a Power hungry Pentium 4 with the works on a 400w PSU for the working adult or an Athlon XP 2000+ on a 400w PSU for the gaming teen.
If there are 2 CRT monitors and 2 LCDS, does the LCD setup really save?

How to calculate the cost and how to reduce power consumption and cost?

 

[jtr1962]

The only way to know exactly is to hook each machine up to a wattmeter. My 1.5 GHz machine with 3 hard drives uses ~100 watts. A PII with a single hard drive will use maybe 80 watts. A Pentium or MMX will use maybe 50 or 60 watts. A 15" or 17" CRT monitor uses up to about 100 watts. An LCD monitor can use only a few watts if the backlight is turned off. I won't add in the power consumption of things like CD or DVD drives unless they're used very frequently.

If you want to save power go with the slowest machine that meets you needs and buy an efficient power supply. Preferably buy a board with integrated graphics, sound, and a NIC. Add in an LCD monitor, and turn it off whenever it's not in use. Only use as many hard drives as needed. Sure, this system may not be the fastest, but it'll be fine for everything except gaming. One big problem nowadays is finding a low power processor. It seems all CPUs made these days consume at least 70 watts. For low power consumption and decent speed you can either use a mobile CPU if you can find a desktop M/B that supports it, or use a M/B supporting either a 1.4GHz PIII or Celeron. These were the last desktop CPUs made to my knowledge that had power consumptions of maybe 35 to 40 watts. With today's smaller processes we can probably make a CPU running at maybe 1.5 GHz that consumes only 10 or 15 watts but too many people are brainwashed into thinking they need 4GHz to surf the web. As a result, the pickings these days are slim if you're looking for low power consumption. Damned shame if you ask me because a 10 watt CPU combined with a cool-running 5400 RPM drive (also a rarity these days) will make a passively cooled, nearly silent system that would be fast enough for 95% of everyone's needs possible. Unfortunately, computers are marketed in terms of speed only these days, even when the touted gains are minimal. For example, access times aren't that much better with 7200 RPM versus 5400 RPM drives. Sure, rotational latency is less but seek times suffer from the faster speed. Net gain is very little and power consumption is 50% more. Of course 7200 instead of 5400 looks better on the box which is why they sell.

To figure total energy consumption multiply the power for each machine in kW (divide the watts by 1000) by the number of hours per day/week/month it is on, add them all up, and you'll get your energy usage in kW-hours. Multiply by your power company's rate per kW-hour and you'll know how much your machines are costing to run. If your power company charges a high rate you might want to replace some fast machines with slower ones. Rates here in NYC run around $0.18/kW-hour, and will soon go as high as $0.43/kW-hour so I need to be energy conscious. All that being said, PCs are probably only a small part of your electric bill. You can probably save more money by replacing your old refrigerators and air conditioners as well as converting all your lighting to fluorescent (go for 4-foot linear tubes rather than CFLs since they are about 50% more efficient). In many cases payback time for upgrading is less than a year. For example, replacing two 100W bulbs with a 2x32W T-8 fixture (~$50) pays for itself in about a year at current NYC rates (assuming 5 hours/day usage), and you get about 65% more light besides. Other ideas include unplugging unneeded adaptors which produce a small but steady drain, not using incandescent night lights (use LED instead), insulating your house, generating some of your own electric via solar power (I plan to do this within 5 years) and turning the TV off when not in use.

 

[Jan Kivar]

The wattages on power supplies are max. rated wattages. The actual usage for a regular computer is around 100-150 Watts. There are devices like Kill-a-Watt which can measure the power used by the computer.

Here's an article (in German) with some measurements. The numbers speak for themselves. They are the total consumption from the wall socket, to the best of my knowledge.

Cheers,

Jan

 

[Tea]

We just upped our electricity bills by 25% — of our own free will. Starting in about two weeks, 100% of the power we use to build & test computers, light the workshop, make cups of tea, and so on, will be solar.

We will thus be making a zero contribution to greenhouse gases (apart from out cars and homes and things, of course.)

The power company is now obliged (by law, I think) to offer consumers the following choices:

1: Standard dirty power: about 90% brown coal-generated, some hydro and other odds and ends. Standard price.

2: 80% hydro, 20% wind. No greenhouse gases, but puts stress on rivers. About $1 per week extra.

3: 50% hydro, 50% wind. Less hydro, but wind generators are not without their problems too, particularly as regards the critically endangered Orange-bellied Parrot. The fear is that the coastal wind generators will kill OBPs arriving at the end of their 200-mile Bass Straight crossing every year. Birds don't "understand" the turbine blades, and there are only about 250 OBPs left.

4: 100% solar. The dearest, of course. But the only one that we can really use with a clean conscience.

Anyway, I guess that means we might have to start paying more attention to our power consumption. Now that it costs us extra, maybe we will get better at switching things off.

 

[Mercutio]

The best thing you can do, WRT to power consumption, is to shut your (CRT) monitor off when you aren't using it. They use tons of power and generate HUGE amounts of waste heat, especially the big 19"+ ones.

Yeah, I leave eight or nine computers on all the time in my house, but I almost never have more than one display turned on.

 

[mubs]

Tea, that's a very conscientious thing you folks are doing, and very laudable!

Birds don't "understand" the turbine blades

Couldn't the turbines be made to emit a suitable noise that'd scare the birds and keep them away?

Merc, the moitors will throttle down to a few watts (< 7) if they are in power saving mode, won't they?

 

[Fushigi]

My 19" NEC-Mitsu SB930 CRT uses something like 85 watts operating and 7-8 watts standby. I wanted to go flat-panel but the tech & price just wasn't good enough at the time.

My wife's PC uses a Samsung 15" LCD. Not bad after about 3 years of use. Power consumption is like 35 watts in use; I don't recall the idle usage. In the end, I wouldn't buy an LCD for power savings as the initial purchase price difference will take many years, probably decades, to overcome (based on current prices). Buy them for the space savings and other features like DVI, but not for power savings.

For the PCs themselves I mostly overbuy on PSUs. The 300W unit in the wife's PC is powering an nForce2 mobo with a Barton 2600+, GF440 graphics, Atlas 10K II SCSI on an LSI SCSI card, FDD and a pair of opticals that get used for watching the occasional DVD or burning a CD once in a while. No supplemental case fans anymore. It's the PSU that came with her Enlight case. My PC has an nForce2 mobo with XP1700+ OCed to 2800+, AIW9600, Tekram SCSI, X15 (original), 2 ATA drives (Samsung 160GB & Maxtor 200GB), FDD & 2 opticals, and a couple of case fans on a 420W (IIRC) Antec TruePower. The PSU is way overkill but for the price difference I've no problem buying a larger unit. My thinking is that it'll more than likely last longer as it won't be stressed as much.

 

[Bookmage]

I'm not sure if power companies in the US are obligated to offer alternative sources. Will have to look into that sometime. IIRC, last time i checked, solar wasn't efficient enough to completely run the whole house. But that was several years ago. Prices have probably dropped a bit, however it is still more expensive than the conventional power.

jtr: Thanks for the info. It's a new house and has lots of energy efficient appliances. Computers are the only thing running 24/7 and that's the thing my mom picks on. And, I still have 5400rpm drives that just *feel* slower when i'm copying files. On my linux box, however, I don't notice it as much, but that could be mainly because I've gotten to the sluggishness of broken Xwindows on a celeron 500.

Do I really save power by shutting down my computer for the 6-8 hours at nite? In our family of four, we have about a dozen computers with half a dozen monitors. I have an 18" LCD for portability and easiness on the eyes. My parents are still running 17inch CRTs from their P3 computers and only use it several hours a day. My mom complains because she has a 21+" LCD at work I run 5-6 computers at any given time and hate having them off for any reason. One monitor, KVM switch. Soon in the basement, I will putting a Media Server and linking up the computers in the house to run off it. Since it's in the basement, she's not really going to notice it. *hopefully*

I'm looking at building a little SETI/BOINC/Folding/waste of time,money,space cluster/stack starting with 3-5 Athlon 2000+ on a SOYO K7VME integrated mobo and 256MB of ram. Would that cause a significant increase to power costs? Just how many computers does it take to really eat up your electric bill? Has anyone noticed a big jump/drop when they turn their computers off for any extended amount of time?

I'll heading to an apt when I get back to school. First time, I won't be able to waste the school's power. Between my roommates and me, there'll probably be 3-4 LCDs, and 5-8 computers. Would it be worth stealing power from the next door neighbor?

 

[Buck]

Nice to have those options Tea. Most of my electricty comes from a nuclear power plant about 5 miles away. Have you looked into generating your own solar energy at the Redhill shop?

 

[Fushigi]

Bookmage, in addition to powering the PCs themselves, you should also account for a slight increase in air conditioning costs if you tend to have to use AC where you live. OTOH, if you have cold winters your heating bill may be mildly decreased due to the radiant heat the PC gives off.

During summer, my den is 3-4 degrees warmer than the rest of the floor it's on. Since there's no other mitigating factors, and I keep my CPU pegged Folding (i.e. maximum heat creation & power consumption), I can only assume it's due to the heat from the PC.

 

[mubs]

Southern California Edison, which serves parts of LA and Orange Counties, is mandated to have some sort of mix with renewable sources thrown in. Don't know the exact ratios; a leaflet came in my last bill. Buck, being in the southern extremes of Orange county, is probably served by San Diego Gas & Electric like I was when I lived in Laguna Niguel.

 

[Buck]

Yes mubs, I am served by SDG&E.

 

[Bozo]

My P4 Prescott is warming my basement office as we speak. :lol:

At work I'm going to try to convince the purse string holders that 600 LCD monitors would pay for themselves over a three year period. (reduced electric use and A/C load.) Most of our CRT monitors start to get fuzzy, and some have the screen 'burned in' after 3-4 years.

Bozo :mrgrn:

 

[blakerwry]

Mage, to give you a comparison. For every computer you leave running, it's aproximately the equivalent of leaving a light bulb on. For every 2 LCDs, assume 1 light bulb. For every CRT it's 1 bulb.

Over time it adds up, but for me I'd guess it's about $18 a month for 2 complete systems, a headless server and my HTPC.

 

[Bookmage]

My dad has habit of using 25w bulbs and just adding 4 bulbs to a ceiling fan. We also have ceiling fans in every room cuz it saves on power over AC. However, I don't think 8 rooms w/ ceiling fans running 24/7 saves a lot over running the AC for 4-6 hours a day.

It's mainly winter during the school year and heating is never a problem. Cooling during the summer and late spring/early fall is something to worry about. However, our dorm rooms never had AC and for the most part I'm fine. Which brings me to something else I'm curious about.

What local shops sell watt meters?
If I get solar panels on roof, can I hook them directly up to a particular socket/plug/area that powers only certain devices, ie. computer, office, more computer stuff

Someone built a mini-itx cluster using DC-DC converters hooked to an AC-DC Power supply. This lets him run one power plug to an UPS and cuts back on wiring. Would that help cut back on power consumption? OR would that be purely geek ..er... coolness factor?
Also, does that mean, that a power supply will pull only the power thats requested? I remember hearing something about a 300w PSU pulling 300w, no matter what was hooked up. This seemed highly inefficient and I'm quite sure that doesn't happen, but I lack paperwork to prove it.

I'm not sure I've seen LED night lights around. I'll have to look for them.
Our is new and insulated according to county codes? We move around too much to make solar panels cost effective. And um... we're lazy?
We barely watch TV and it's off most of the time.

Do notebooks power requirements function the same way as a desktop? Or does it function as if working on a battery, conserving 90% and kicking into full gear when needed? I'm thinking of picking up some Athlon Mobiles to power some boxes and possibly underclocking them. Would it be better to have a bunch of weak computers and one power hungry computer? OR to run a bunch of medium powered computers pulling somewhat stable electricity?

and Power companies should offer unlimited power plans, like for 100$, get all the power u want. Or get the Power User Plan and get xx# watthours for free. Maybe I should order that solar power kit in the back of my popular science mag....

 

[blakerwry]

Computer power supplies pull only what they need. They are usually pretty efficient too. Atleast 75% I believe, the better quality PSUs are more efficient... upto almost 90%

Power supplies have a range at which they are most efficient. Deviate from this range, either higher or lower and they will be less efficient. I beleive a typical computer PSU is most effective when ran at about 3/4 to 4/5ths of its true max.

In any kind of conversion though there will be losses, so I don't see any reason for the unnecessary converters, it will simply add to more loss.

 

[The JoJo]

Here's some information about how the power output varies due to temperature/load and so on:
http://www.silentpcreview.com/article28-page2.html

I think the highest that silentpcreview has measured was 82% efficiency.

 

[Bookmage]

ooo neat...
now to find some of these more effecient power supplies...
and i a found a device called a kill-a-watt which measures wattage from a device plugged into it. Now to find a store that sells it.

Anyone have any experience with this item?

 

[Howell]

The power company that services your building will be able to tell you what they charge in KW/H. Once you calculate your load you can calculate the costs.

 

[Pradeep]

Rates here in NYC run around $0.18/kW-hour, and will soon go as high as $0.43/kW-hour so I need to be energy conscious.

Dear jebus. 43 cents per kW/h? Insanity. I pay 7.04 cents in Upstate and bitch about that All nuclear tho. However in Tassie it was all Hydro (except when the catchment levels dropped every couple of years/or turbine maintenance and they had to fire up an oil fired station for a few weeks. I guess it all evens out.

 

[blakerwry]

The power company that services your building will be able to tell you what they charge in KW/H. Once you calculate your load you can calculate the costs.

I was reviewing my bill and no where does it state the charge per kW/hr

So I just took the total cost and divided by the total kw/hr used to find out how much they are charging per kw/hr. ;-(

Turns out to be just under $0.09 per kW/Hr.

so I estimated each PC w/ monitor takes ~$8 per month to operate and my headless one takes about $7... The HTPC not being used much takes up very little. However, my electricity bills have been as low as $34/month which makes me think I'm over estimating the cost for the computers.. that, or the rates change periodically.


However, with Summer here my electricity bills are going back up. Last month it was in the $50's. I think this time last year the bill was around $60.00.

 

[Fushigi]

I was pretty happy that last month's electric bill was under $200.

 

[jtr1962]

Rates here in NYC run around $0.18/kW-hour, and will soon go as high as $0.43/kW-hour so I need to be energy conscious.

Dear jebus. 43 cents per kW/h? Insanity. I pay 7.04 cents in Upstate and bitch about that All nuclear tho. However in Tassie it was all Hydro (except when the catchment levels dropped every couple of years/or turbine maintenance and they had to fire up an oil fired station for a few weeks. I guess it all evens out.

Thankfully, that's only a proposed rate increase which may never see the light of day. They're thinking of implementing a system where they charge more during peak usage periods. The $0.43 would apply to peak usage during summer months. Of course, the rates will be the same as they are now during non-peak periods instead of lower.

I blame all the NIMBYs for our high power rates. Every time a new nuclear plant was proposed they all bitch about and it ends up getting shelved. Shoreham was shelved after a few billion dollars were spent on it, so of course those costs are passed on to the consumer. Thankfully, we don't have LILCO over here, but everyone on Long Island does, and pays more than we do. Nuclear is the only cheap way to make power everywhere. Hydroelectric is good if you ignore the environmental damage but it can't be used unless you have a river to dam.

I'm seriously thinking of using solar for all our power needs in the next few years. Solar cells, batteries, and inverters for household electricity and solar heating for heat and hot water. I'm tired of being at the whims of ConEd and the heating oil companies. Oil is only going to go up while the cost of solar panels goes down. It's looking better every day for solar.

BTW, the electric bills here average about $250/month in the summer, and we've already converted to fluorescent lighting (mostly the more efficient T-8 linear tubes) with the exception of three infrequently chandeliers in the dining room, master bedroom, and living room. We'll put LED bulbs in those once they come out (should be by about 2007).

 

[Bookmage]

LED bulbs? > fluorescent?

What about keeping the rooms cool while keeping power low? We've already got fans in most rooms but one room facing the sun always cooks at >82F during the day. There's only 3 comps in there and they don't produce that much heat. Even with the window open and the fan blowing it stays pretty hot.

It may be bad air circulation or just a cursed a room. Either way, I'm working on bringing the temp down to a nicer 78F.

 

[jtr1962]

LED bulbs? > fluorescent?

What about keeping the rooms cool while keeping power low?

That's among the reasons why I use fluorescents-to reduce the heat load on air conditioners, and it can make a substantial difference. In my bedroom I would need about 500 to 600 watts of incandescent lighting to give the same lighting levels as my 4X32W tube fixture which uses ~110W. In my workroom the fluorescent lighting draws about 210W. I would need ~900W incandescent for equivalent lighting levels. Between these two rooms I'm saving well over 1100 watts in power consumption. Add in the kitchen, and the total is maybe 1600 watts saved. And this isn't even getting into the much nicer 5000K color temp produced by the fluorescents I use. Much better than the ugly yellow light produced by incandescents.

We've already got fans in most rooms but one room facing the sun always cooks at >82F during the day. There's only 3 comps in there and they don't produce that much heat. Even with the window open and the fan blowing it stays pretty hot.

3 computers even without the monitors on is a substantial heat load (300 to 400 watts if they're fairly recent machines, or about the same as a large refrigerator). That is one of the reasons the room is hot. I'm not sure ceiling fans (or fans in general) are the best way to cool a room. I hate fans-they just blow dust from one part of the room to another. Past a point you need active cooling. A small (~5000 BTU) air conditioner will nicely cool an average sized, well-insulated room for probably not much more electricity than the ceiling fan. Most of those ceiling fans use maybe 100 or so watts. A small A/C might use 500W. The A/C will cycle on and off to maintain temperature, so on average it might only use 50 or 100 watts more than a ceiling fan which is on 24/7. And as a bonus you remove humidity (a big problem here during New York summers). If you have many small air conditioners on then central air is a way to cool and save yet more money. Many central air units have EERs over 17 (compared to ~12 maximum for room air conditioners). Some can also run in reverse as heat pumps in the cool months and provide ~3 watts of heat per watt of electricity.

 

[Buck]

Those 4x32W fixtures are very nice. I use them in my garage/workshop. I'm planning on hooking one up to my garage door opener instead of using that woefully inefficient incandescent bulb they come with. However, this is not to save energy, but instead to provide adequate lighting when the door opens.

 

[jtr1962]

Yes, that's my main reason for using them as well-to provide adequate lighting while not consuming an inordinate amount of power. I wouldn't have seriously considered putting 600 watts of incandescent in my bedroom if the 4x32w fixtures didn't exist, but I did have 2 200 watt bulbs in there for a few months before I put in the first fluorescent fixture. I find that the levels to which most people light their houses are totally inadequate (I don't consider a typical 100W bulb or 26W CFL in a table lamp to be adequate). I generally use 75 to 200 lumens per square foot as a guideline, with the lower end being for bedrooms and the higher end being for bathrooms, kitchens, and work areas. I think a 100W bulb in a 100 ft² room works out to ~15lm/ft²-totally unacceptable in my view. Truth be told, if power consumption wasn't an issue I would probably light most of where I live to around 1000 lm/ft² (about 1/10 the intensity of a sunny day), but even with fluorescent this would mean over 1000 watts per room just for lighting.

 

[Grim]

Keeping sun-facing rooms cool

LED bulbs? > fluorescent?

What about keeping the rooms cool while keeping power low? We've already got fans in most rooms but one room facing the sun always cooks at >82F during the day. There's only 3 comps in there and they don't produce that much heat. Even with the window open and the fan blowing it stays pretty hot.

It may be bad air circulation or just a cursed a room. Either way, I'm working on bringing the temp down to a nicer 78F.

Disclaimer: The below assumes that either your average summer day is cooler than 82F, or you have active cooling of some sort.

Let me recommend you do something about that sun. The sun beating on the windows is almost certainly going to be your biggest heat source, followed by it beating on the walls. Unless you address that issue, you're wasting your money. (Of course, if that issue has already been sufficiently addressed, nevermind. But since the room is over temperature, it probably hasn't been.)

Awnings can work. However, they tend to only be really helpful from around 10am to 2pm, with the exact time varying per location. Frequently, they don't really go with the decor.

At least one company makes a black metal screen, which one can affix to the outside of their windows, which works wonders. Admittedly, the screen itself gets pretty hot, which in turn conducts heat into the house at the contact points, but it's a lot less than would come through the window. I'm led to understand that these tend to be ones most economical quick solution. If you want me to find a link, I can probably do that. I don't have it on hand because my current apartment complex has specifically banned them (they feel they don't go with the decor.)

Heavy drapes can work. As they're inside, they are of only limited effectiveness, and there can be difficulties getting the mounting brackets fastened securely enough; it's also possible that one has a decor problem again. This is, overall, probably not a cheaper method than most of the others mentioned here.

Also, one might look into IR coatings for ones windows, or special "smart windows"; while these frequently are very expensive, they do apparently pay off in the long run. If you're not planning on owning the home for more than 20 years, however, you probably don't want to go there.

Another long-term option is, of course, planting trees or tall bushes, sufficiently far from the house so that the roots won't get to the foundation, but near enough so that they'll (eventually) shield the house from the sun. When I lived near Chicago, our house had tall bushes along the south side of the house, and a row of tall (50+ year) pine trees about 30 feet away; the southern rooms were not appreciably warmer than the northern rooms during the summer, even without the AC on.

Regarding the walls, a certain amount can be addressed by painting the house with an appropriate paint. However, I've never seen any of the really good varieties as far north as VA; I suspect that means you don't need to go this far.

 

[blakerwry]

my god jtr, I would probably get a tan just sitting inside your house.

Would you believe my entire living room is usually lit by a mere 18 watt CF bulb after daylight? During the daytime there are 2 large windows that let light in.

The bedroom is lit by a single 75watt incandescent bulb, and again a large window.

Come to think of it, there is a window in every room of the apartment except for the bathroom.

 

[jtr1962]

my god jtr, I would probably get a tan just sitting inside your house.

:mrgrn:

Would you believe my entire living room is usually lit by a mere 18 watt CF bulb after daylight? During the daytime there are 2 large windows that let light in.

I believe it because I've seen the same thing over and over in many homes. The big problem I find with doing this is the huge difference in light levels between day and night. To compound the problem, most people either use incandescents or the more common warm white CFLs. This makes the colors in the room look way different at night than during the day. Yellowish light combined with low lighting levels just gives me a huge headache. Fluorescent light on a flickering magnetic ballast does the same thing. I'll guess most people don't spend enough time in their homes at night to notice how bad the lighting is. If you're watching TV or at the computer your eyes aren't really paying attention to the how the room is lit. Since I'm awake a lot at night I do notice. This is why I redid the lighting in a good portion of where I live. Most of this upgrading involving changing over to full-spectrum tubes and electronically-ballasted fixtures. I'll be going exclusively with full-spectrum 5000K CFLs once the ones we're using start to burn out. I'm getting to the point that I can't really tolerate anything else, or low light levels, for any length of time except when I'm sleeping.

 

[jtr1962]

Here's a picture of my workroom:

The two fixtures in a row are using GE T-12 40W Chroma 50s. The other one is using T-8 32W Paralite Maxum 5000s. The GE tubes render deep reds a little better but other than that there doesn't seem to be much difference between the two. They're both pretty close to sunlight. The T-8 fixture actually gives off about 1.5 times the light of each of the T-12 fixtures while using 64W instead of 73W. When the GE tubes go in a few years I'll be using exclusively T-8s, and will have light levels about 30% higher yet will use about 20W less power.

 

[Howell]

A small (~5000 BTU) air conditioner will nicely cool an average sized, well-insulated room for probably not much more electricity than the ceiling fan. Most of those ceiling fans use maybe 100 or so watts. A small A/C might use 500W. The A/C will cycle on and off to maintain temperature, so on average it might only use 50 or 100 watts more than a ceiling fan which is on 24/7.

The ceiling fans I bought a couple months ago use 9.5W on the lowest setting (1613RPM) and 65W on the highest (5687RPM). They cost between. 40 and $70. Don't remember exactly.

 

[Grim]

Would you believe my entire living room is usually lit by a mere 18 watt CF bulb after daylight? During the daytime there are 2 large windows that let light in.

Some people! A 14 watt CF bulb is more than sufficient for me. :cyclopsani:

I'll guess most people don't spend enough time in their homes at night to notice how bad the lighting is.

Given the comments I hear from my cowokers about this topic, I'll suggest that, at least for those I personally know, the issue is more that people aren't spending enough time either outside or in the presence of windows during daylight hours to be adjusted to "normal" lighting conditions. I know I certainly am not.

I do have trouble tanning from standard florescent light bulbs, like they have at work; I think it's the fact that they're missing the necessary UV wavelengths.