proper wattage

There is not a direct correlation between wattage and room light - wattage is a measure of power consumption, not light output. Different types of lamps emit differing amounts of usable light at the same wattage. For example, a 45 watt fluorescent lamp does not emit the same amount of visible light as a 45 watt incandescent lamp.

To solve the problem, you need to know two pieces of information: 1. What will the lit area be used for? (area lighting, task lighting, reading...) With that information, you can consult an architectural manual for recommendations on light intensity (in lumen per square foot). 2. What type of lighting will be used? From that, you can consult the manufacturer's information for light output (in lumen) for each size lamp available. (lamp meaning "bulb" here) From that the equation you're looking for is:

lumen per square foot = # of fixtures X lamps per fixture X lumen per lamp X C.U. X M.F. / room area (in square feet)

where:

C.U. is coefficient of utilization (amount of light emitted that is actually usable at the work plane - 0.5 is a good estimate for most room conditions)

M.F. is maintenance factor (accounts for reduction of light emissions as lamp ages - 0.8 is a good estimate for most residential light sources)

Hope this helps!

I agree totally with your formulas etc. but to quote you..

For example, a 45 watt fluorescent lamp does not emit the same amount of visible light as a 45 watt incandescent lamp.

You are correct, the amount of light is not the same, but I get the inference that the fluorescent lamp gives out less light.

Did you really mean to make the above statement?

I'm talking actual watts input, not manufactures equivalent bulb size.

The books indicate that 45 watts into a fluorescent lamp will give considerably more total light than 45 watts input into a incandescent lamp, mainly because the the higher efficiency of the florescent lamp and high heat energy loss in the incandescent lamp.

What say Ye...

Snakers

Thank you, my verbiage was hasty. I did not mean to infer the fluorescent lamp would give out less light than the incandescent, only that it would not be the same. You are correct that a fluorescent lamp is much more efficient in generating visible light and less energy is lost to heat. I'll have to speak sharply to my editor!

You were completely right in the first place as a Fluorescent light is far more efficient than an Incandescent. LEDs are even more efficient.

Incandescents use approximately 95% of the energy to make heat, an unnecessary byproduct and although a Fluorescent gets slightly warm, its efficiency is much, much higher.....usually around 5 times...... Halogens are about 1% better than incandescents (which they still are), which is really a drop in the ocean....

The original poster should learn how modern lighting is not only far more energy efficient, but also dramatically reduces the heat in a room when the temperatures are high outside, so that you don't have AC using electricity fighting to remove this heat, also generated by electricity!! It just costs extra money.

Theoretically, in a cold country, where electrical heating only is the norm, then it does not matter as much, but how many places are like that?

The original poster should try and find a lighting manufacturer that runs training classes to help him with all the new lighting forms and how to put them to correct usage in homes and offices....

To quote you..

Theoretically, in a cold country, where electrical heating only is the norm, then it does not matter as much, but how many places are like that?

Right, if your electric heating is totally resistive, however we (USA) would consider heat pumps as electric heat and would have to consider the trade off of the energy ratios of resistive heating vs a heat pump. Of course, in the Northern climates, there is no source of heat, and it MUST be totally resistive. I spent too many years freezing my tail off in the Northern climate before I moved a little further South.

Snakers

My comment was to differentiate between heating that only uses Electricity and gas, oil, wood or pellets etc etc Which are generally cheaper (at this time) than Resistive heating.....

Its depends on your area of room and how much liminar do you hope?

and all thse correlate to type of lamp.

different lamp has different lighting.

if you are going to keep fashion., try to use LeD lamp. all color and shape .and highest lighting efficiency.

Can u tell me the minimum lumen required in houses, factories, offices, conference rooms and restaurants?

Yes , very clear.

except this specification, there are also many other specification for your selection lamp, for example, color tempereature, visible figure( how to say in english? means apperance color index) etc.

sometime people require your to take account of art creature. size, power dissipation. etc.

That's when you know it's time to hire a specialist! Be sure to add 10% and pass the cost along to the customer!

Also these lighting intensities come along with a luximeter on a printed form.

What do you mean by your statment light levels? Are they levels of a luminaire from the floor or workplace and what are the units, or perharps you mean the number of luminaire to be placed,or perharps you mean is it the lighing intensity?

Which one as they all have different requirements? Your own country of abode will have such regulations, you need to find and use them.....there is no minimum for all.

Sorry.

As a furniture salesman, you should know that there is no "right" answer to your question.

Yes, there are plenty of standards and building codes that attempt to set the proper level of room lighting.

But, let me ask you-- in your experience, what is the proper color of a couch? Answer-- IT DEPENDS!

The proper level of room lighting, as specified by codes and standards, is arrived at by compromise-- and then, the attorneys add several extra lumens to make sure the room owner does not get sued because someone tripped over an invisible obstacle!

It depends? On WHAT?

Let's use a fun hypothetical--

Assume:

1. You are a hormone-driven heterosexual male.

2. You are in bed with a luscious, young female specimen that delights the eye.

You want PLENTY of lumens to burn every detail of this moment into your memory cells! The proper level of lighting for this bedroom? HIGH, VERY HIGH!

Change assumption #2 as follows---

2. You are in bed with a coyote (google the slang, if you don't know what that means!)

Now, the proper level of lighting for the bedroom is LOW, VERY LOW!

I am in the computer business. I regularly make office workers much happier by removing two of the four flourescents from each of the fixtures in dropped ceilings above their desks. Why? The codes & standards have prescribed TOO MUCH ambient light for them to work COMFORTABLY on their computer screens all day. With lower levels of surrounding light, they end their day less fatigued-- and HAPPIER!

Let's go another way. Ever heard of a DIMMER SWITCH?

People love them-- because they PERMIT THEM TO ADJUST THE LEVEL OF LIGHT IN THE ROOM TO SUIT THE CURRENT USE OF THE ROOM, OR TO PROVIDE FOR A DIFFERENT AMBIENCE IN THE ROOM. The "proper" level in the room is a moving target!

Consider another factor-- Flourescents pulse or "flicker" at the frequency of the AC current they are connected to-- usually around 60Hz in the US. If your computer CRT, or your TV, fan, or your rotating power saw, or other item is scanning or moving at a close harmonic frequency, the user will perceive an annoying "flicker" when viewing the item. You can change either the frequency of the scanning, the RPM of the rotating object, or the type of lighting-- to remove the annoyance.

How about lighting temperature? Move that couch to your parking lot-- under those sodium vapor lamps-- and you've got to special-order new upholstery! Why? The color changes! Flourescents, incandescents, and vapor bulbs all produce different color temperatures. Within each class of bulbs, different effects are possible.

Let's not even get into the interactions among wattages, fixtures, shades, wall and floor colors, and many other factors. The same wattage (and fixture) that adequately illuminates a room with white walls may not perform sufficiently in a room with walls of a less reflective color.

Lighting types and levels are much like furniture upholstery colors. Learning how to specify the "proper" fixtures, bulbs, and wattages is like learning how to specify furniture colors and styles. WHAT IS PROPER IS WHAT MAKES THE USER MOST COMFORTABLE AND MOST ABLE TO DO WHAT THEY WANT TO DO IN THE PLACE THAT IS BEING LIGHTED.

Unfortunately, codes and specs provide only a starting point. You cannot properly specify lighting wattages, bulb types, or fixtures "by the numbers." To get "good" at this, you must learn by experience, by listening, and, yes, by screwing up occasionally.

Reminds me of an old joke-- Two old tailors are partners in a haberdashery. They remodel their ancient store-- at great expense-- to try to boost sales. At the grand re-opening, a customer comes in and asks for a green suit. Immediately, one tailor yells back to the other tailor, "Hey, turn on the green lights-- the man wants a green suit!"

You guys are being too complicated for this chap. A quick answer residential lighting is 1 - 3 watts per sqft. A room 10x12 12 120 sqft that would mean 120-360 watts so simply said, add up the watts in the bulbs of the fixture and see if that is enough. As we get older or it is an area needing more light use 3 watts per sqft.

you are giving an experience value for lighting.

Im afraid 300w seems too brightness for an such room. ofcause fro a shopperman he like bright. he can use 3x100 to get more balance and avarage light.

if he use fluorescent lamp, 40-60w enough for a 20-30M^2. but if its sve energy lamp only 20w.

Illustrate you one of our scene lighting project.

Lter I shall post a inner lighting for decoration or shop.

furniture lighting.

Nature and manmade lamp lighting

It would appear that you still use incandescent/Halogen bulbs in some areas, is that true?

No, they are not incandescent bulbs. but compact save energy fluorescent lamp. From the ceiling you can find their form.

There are kinds of type these lamps in my house as well as many modern chinese home. there are sitll a few families like my mother and those old people living room keep some the old incandescent. They get use to the warm tone instead of such cool tone shed from the fluorescent lamp.

There is no need to have the old cold white in either FLs or CFLs, also high power LEDs nowadays offer "Warm White" as an option.....I have bought both and relatively recently (in the last month).

There is an economic issue.

fl has higher tone, as wellas cfl, tehy still has huge market . cheaper.

now warm white lighting put into use in china as well. many facotry manufacture this led lamp, it really good, but price is a problem.

we can only offer 200w max for street lighting, despite 300w has been made out.

But in winter, I like to use an old large ppower bulb 200w-300w in room in the ringt sometimes when heavy snow is melting, I feel its very warm.

If you like lighting,

I can open a thread to deal with it. inside, outside.

I like those beautiful color in the night. but its real wast energy.

I see on tv, NY , germany, europe steets use it as large screen, very charming. our china hs as well, but not so popular as yours.

LED's and E savings interest me. I have used the small "white" led's in the 'normal' low voltage fixture style. They light up and are kind of like moonlight. There are 20 led in each light bulb and I estimate that each group of 20 in each light bulb would use about 1 watt at 12volts.

Just how efficient are led lights in comparison with flourescent lighting. Are they a viable alternative to light our homes in 2008?

High power warm white led lighting...What is high power...200 plus watts? Where can one source a range of viable effective led lighting for domestic use? Thanks. Harry

Although I am a strong proponent of LED & CFLs in the house and office, and I am using quite a lot of them at home, I would be lying to you if I even tried to pretend that I am an expert in this area, I am not.

But I can say that if you use the GU10 fittings (mains voltage), you have a wide range of good power saving lamps to choose from.....I personally would not plan for any more 12 volt systems as then ONLY LEDs will work (I believe) at this voltage!! Or at least, there are few CFLs for this voltage, and they will be more expensive too!

May I also suggest that you probably need to double the amount of fittings you install, particularly where LED lighting is going to be used as the LEDs, though improving almost daily, do not deliver the same amount of light under the same conditions as incandescent do/did!! You will still show massive savings.

CFLs are getting to be very good and come in both GU10 and screw fitting for mains voltage. It is worth looking car5fully as sometimes the screw fitting types, although the same in all other repects, are significantly cheaper. I have no idea why!!

My hall has the incandescent equivalent of 650 watts of light, but only uses about 80 watts of actual power. I am using mostly CFLs, but a couple of LEDs on the upper levels as well. At night, it appears to be almost daylight levels of light!!

There are COLD white and WARM white LEDs and CFLs, my wife does NOT like the COLD ones at all. The ones I already have (LED) I use mixed in with the CFLs to illuminate instantly when the light is switched on, whereas the CFLs are of a type that will last a long, long time, but need a few seconds to get going at all and a minute to get to full brilliancy....the instant switch on ones tend to have a far shorter life!

If you need dimmable CFLs, then Megaman have a special range that allow themselves to be dimmed (most do not!)...

The biggest problem is the price, these energy saving lamps are all much more expensive than normal bulbs and need to work for many hours before you get payback! Using them in areas of extreme cold (CFLs) can also be a problem. Do not use them in places where you only need them switched on for a few hours or less per month....

Experiment with them a bit before spending serious money, include your partner in any decisions from day 1!! A lot of the really attractive fittings available in Germany have a strange bulb (mains voltage) with a glass and wire plug in base, no other metal. These lamps CANNOT be replaced with either CFLs or LEDs at this moment in time!!! Be warned!!

There are plans afoot to have a "lighting Blog" from one of the CR4 Guys (Don), he is in the business and willing to do it, but just working for a living is getting in the way for the moment!!! But he has promised me that he will get the blog going as soon as he has time. So may I suggest that you wait a little for his offerings, which will be far more up to date than anything that I write about!!

Thank You Andy. I await the lighting blog. I'm never in any particular rush and also don't give up the quest for learning. Harry

No problem, have a great day.

Halgon bulb used to use in news gather, film projector, car headlight, square lighting or gymnasium, school etc large sites.

street lighting are widely using HV sodium lamp. and large power led, 100w,200w begine to install along side street. which have a around of warm tone at 3200-3900 degree.

I admit your germen is still a strong at lighting. we learn much from your country. and other europe contries

next, I can post a photo, you can guess where it is?