How much light does a room need?

Discussion in 'Building Construction' started by kickaha(remove), Jan 14, 2004.

  1. Hi, all-

    Is there a rule of thumb for the amount of lighting that should be
    installed in a room?

    So many watts per SF?

    The room in question is a bonus room and will be used for all kinds of
    stuff. We're thinking of 3 way fluorescent fixtures.

    kickaha
    kickaha(remove), Jan 14, 2004
    #1
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  2. kickaha(remove)

    JR Guest

    In article <>,
    "kickaha(remove)" <"kickaha(remove)"@workmail.com> wrote:

    > Hi, all-
    >
    > Is there a rule of thumb for the amount of lighting that should be
    > installed in a room?
    >

    Enough to offset the dark.

    --
    -JR
    Hung like Einstein and smart as a horse
    JR, Jan 14, 2004
    #2
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  3. kickaha(remove)

    Richard Guest

    kickaha(remove) wrote:

    > Hi, all-


    > Is there a rule of thumb for the amount of lighting that should be
    > installed in a room?


    > So many watts per SF?


    > The room in question is a bonus room and will be used for all kinds of
    > stuff. We're thinking of 3 way fluorescent fixtures.


    > kickaha


    I'm using a two-tube shop lite in my mobile home living room as a source of
    light.
    It's enough to lite about 2/3 of it with ease.
    so the room size would be like 14x35 or so.
    3 shop lites would be more than enough for that size room.
    $5-$7 each with the lites and the lites last 5 years.

    You could divide the room into 10x10 ft sections. Each section gets a lite.
    Install one and see what it gives out. If you don't need as many, increase
    the section size.
    Richard, Jan 14, 2004
    #3
  4. kickaha(remove)

    Richard Guest

    Lawrence A. Ramsey wrote:

    > I believe the correct figure is 3 watts per sq. ft.
    > 10 x 10 room = 100 x 3 watts sq ft= 300 watts


    Put the sunblock and sunglasses on then.
    And do be sure you have plenty of juice to run those bulbs with.
    While you're at it, buy stock in the light bulb company.
    Richard, Jan 14, 2004
    #4
  5. kickaha(remove)

    Richard Guest

    Lawrence A. Ramsey wrote:

    > Well Richard, since you know what is the correct figure, what is it?
    > Don't condem unless you know that correct answer.


    The correct answer is, sufficient lighting to suit your needs.
    My single shop lite is sufficient to light up 14x30 with no problems.
    If I needed to, I'd even put in a second one.
    So let me see here, 14x30 =420 sqr ft.
    two 40 watt bulbs.
    420 divided by 80 = 5 watts and change.
    So you are in the ballpark of being correct, but your methodology sucks.
    Your method says I need over 2,800 watts of light.
    Ok, 2800 divided by 80. equals a little over 30 shop lites for the same
    area.
    I don't believe I have enough space and electricity for all those lites.
    Richard, Jan 15, 2004
    #5
  6. kickaha(remove)

    Bruce Brown Guest

    Here's my niclels worth

    the "rule" is based on lumens or the amount of light at the floor level. it
    is verified with a simple light meter.

    the "rule" is not the same for a home as it is for a restaurant and
    different again for a school.
    i believe that 1.5 lumens (also translated to candle watt) is the rule for a
    public school

    The reason that the meter is set at floor level is quite simple, some
    ceilings are higher than others and a light bulb at any given wattage
    provides light according to the manufacturer and even more importantly is
    the type of fixture

    Good luck,
    Bruce


    "Lawrence A. Ramsey" <> wrote in message
    news:...
    > Most rooms are underlighted; in a residnece this may not be a bad
    > thing. Many people even like it this way. Depends on your preference
    > for light. I happen to have bad eyesight so the more light the better
    > (to a point, anyway).
    >
    >
    > On Wed, 14 Jan 2004 14:58:41 -0000, HerHusband <>
    > wrote:
    >
    > >>>Is there a rule of thumb for the amount of lighting that should be
    > >>>installed in a room?

    > >
    > >> I believe the correct figure is 3 watts per sq. ft.
    > >> 10 x 10 room = 100 x 3 watts sq ft= 300 watts

    > >
    > >Even if that's an accepted rule, it seems rather high to me, at least for
    > >most living areas. I mean, I only use 7.5 watts per foot for my electric
    > >heaters! We have 120 watt fixtures in most rooms of our home, including

    our
    > >11x12 bedrooms. That works out to just over 1 watt per square foot.
    > >
    > >Most ceiling lights you'll find in stores use two 60 watt light bulbs, or
    > >approximately 120 watts total. These provide plenty of light for most
    > >bedrooms, hallways, closets, laundry rooms, etc. You'll probably want
    > >additional "task" lighting in the bathroom and kitchen though.
    > >
    > >Depending on the use of the "bonus" room, you might also want additional
    > >light for playing games, doing puzzles, exercizing or whatever. Probably
    > >best to accomplish this with multiple fixtures to reduce shadows and
    > >provide more uniform lighting.
    > >
    > >Just my opinion...
    > >
    > >Anthony

    >
    Bruce Brown, Jan 15, 2004
    #6
  7. kickaha(remove)

    TKM Guest

    kickaha(remove) <"kickaha(remove)"@workmail.com> wrote in message
    news:...
    > Hi, all-
    >
    > Is there a rule of thumb for the amount of lighting that should be
    > installed in a room?
    >
    > So many watts per SF?
    >
    > The room in question is a bonus room and will be used for all kinds of
    > stuff. We're thinking of 3 way fluorescent fixtures.
    >
    > kickaha


    Abundant lighting (40 - 50 footcandles) in commercial buildings today runs
    1.0 - 1.5 watts/square foot. Typically, that would be fluorescent. A good
    designer can do clever things and get a good job at slightly less than 1
    watt/square foot.

    Residential lighting is usually task oriented or uses some combination of
    general and task lighting with incandescent lamps so it's less than half as
    efficient. Except for certain visual tasks, however, such as reading or fine
    detailed work, you don't need 40 -50 footcandles either. So, if you're
    estimating electrical load 1 - 2 watts/square foot should be plenty.

    If you're designing lighting based upon watts/square foot, don't. The
    resulting system will likely turn out to be inappropriate or wasteful or
    both. Good lighting is designed for the visual and aesthetic needs of
    people, it's worth finding out how to do it properly.

    TKM
    TKM, Jan 15, 2004
    #7
  8. kickaha(remove)

    Al Barnhard Guest

    No one has yet made what I think is a big point (since I'm 66 years
    old). As a general rule, the older you are, the more light you will
    need to see well.

    See, for example, "Lighting and Our Aging Eyes" at
    http://www.lighttechdesign.com/agingeyes.htm

    Al Barnhard

    On Tue, 13 Jan 2004 19:44:40 -0800, "kickaha(remove)"
    <"kickaha(remove)"@workmail.com> wrote:

    >Hi, all-
    >
    >Is there a rule of thumb for the amount of lighting that should be
    >installed in a room?
    >
    >So many watts per SF?
    >
    >The room in question is a bonus room and will be used for all kinds of
    >stuff. We're thinking of 3 way fluorescent fixtures.
    >
    >kickaha
    Al Barnhard, Jan 15, 2004
    #8
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