Another Lighting Question !

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  • TT_Gully
    Automated Home Jr Member
    • Dec 2009
    • 12

    Another Lighting Question !

    Hi All
    I posted a few months ago regarding a lighting question and since then have trawled the internet looking for possible solutions but ultimately just getting more and more confused.

    What I am trying to do is replace the central decorative light in our living room with a number of recessed down lights which I can then control using HA to give various mood lighting effects. The room is 5m long by 3.5m wide with a ceiling around 2.3m high.

    So the first question is how many lights and of what type? I need to light the room brightly for general use but also be able to reduce the lighting to 2 task lights over the seating area. I have looked at various options including dimmable lamps or a mixture of different wattage lamps to give the same effect. I have experimented with X10 LM12W and love the controllability which this gives. The only problem with this is the running cost of using normal GU10 / MR16 Halogen lamps which can easily be dimmed. This is why I then started to look at using X10 appliance module to simply turn the lights on or off and therefore could use CFL lamps. The plan being I could have the lights controlled by 2-3 modules and be able to turn on or off the lights to give the required effect. I have looked at LED but am unsure if these would give enough light spread to avoid bad shadowing. Also cost is a large factor given that I may need quite a few lights.

    So in summary . . . . . . . .
    How many lights to light the room adequately?
    Standard GU10 / MR16 Halogen, CFL, LED, Mixture? (Purchase cost V Running cost)
    Lamp specification ie wattage, angle?
    To Dim or not to Dim?

    Sorry for the number of questions but I was hoping to start the decoration/rewire soon so need to get a finalised plan together.

    Thanks
  • toscal
    Moderator
    • Oct 2005
    • 2061

    #2
    Bit busy this week, but I can do a quick lighting calc, by the end of the week (hopefuly) for you and tell you the recommended number of lights. Either GU10 50W or GU10 or MR16 6W LED.
    We hope to have our mains dimmable LED lighting out by end of July.
    What is the room used for, as this will give me a starting point for the light levels.
    IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
    Renovation Spain Blog

    Comment

    • toscal
      Moderator
      • Oct 2005
      • 2061

      #3
      Finally got round to doing your lights.
      Hope you don't mind but I have posted them here.
      Recommendations say 300 to 500lx for a Lounge. With 500lx being needed when you want to read a paper do a crossword etc.


      With the LED lighting using our 5W Warm White Cree 60 degree beam angle all in one recessed fitting you would need about 48 or a total of 240 watts. Average lighting level is 366lx


      The iso line values are green 100lx, yellow 200lx and red 350lx.So areas inside the thered line will be at least 300lx. iso lines are at a height of 85cm.

      First picture autohome2.jpg is calculated using POVray, , the second autohome3.jpg is using the software's own ray tracing program and the third autohome.jpg is the quick calc the software does which is also used as the input for the POV file.


      Hope this helps.
      Oh sorry the furniture is a bit sixties/seventies
      Attached Files
      Last edited by toscal; 9 May 2010, 10:01 AM. Reason: for got to mention beam angle
      IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
      Renovation Spain Blog

      Comment

      • TT_Gully
        Automated Home Jr Member
        • Dec 2009
        • 12

        #4
        Hi, thanks for the calculations. 48 lights in such a small room sounds like quite alot. What would be the cost of the units which you specified ?

        Comment

        • Andrew Millne
          Automated Home Ninja
          • Nov 2007
          • 269

          #5
          48!! for a 5mx3.5m room? That can't be right surely. I'd be considering a different lighting source if I were you. I would guess 48 LED downlights would be the equivalent of over 1kW-1.5kW if regular halogens were used?

          I would have thought 10 max.
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          Comment

          • toscal
            Moderator
            • Oct 2005
            • 2061

            #6
            It is quite a lot of lights. But this is if you want the whole room to be at exactly the same brightness, everywhere. The software just calculates the room as a whole so doesn't care whats in it. Thats where the raytracing comes in to enable you to see the difference in lighting levels.

            I have redone the calculations with 20 lights, and this could be OK. But you average about 300lx around the seating. Have included the new 3D with iso lines. I have changed the value of the red to 300lx
            The biggest problem with lighting design, is that some people prefer a bright room others like it darker, and prefer to use standard lamps to provide the extra light needed when reading etc. Plus then the health and safety guidelines also have minimum recommended levels for various things.
            Attached Files
            IF YOU CAN'T FIX IT WITH A HAMMER, YOU'VE GOT AN ELECTRICAL PROBLEM.
            Renovation Spain Blog

            Comment

            • Andrew Millne
              Automated Home Ninja
              • Nov 2007
              • 269

              #7
              I think a mixed lighting scheme may be the answer. Downlights for task lighting set over certain areas. A large main light for general lighting. Combine that with some floor/table lamps and you have a good choice of lighting options.
              Visit my blog and Follow me on Twitter...

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