I understand what you're saying,
I dont think you do. If you did, you'd understand the folly of this sentence:
every shop I've been in that has ~50 lum/sf seems dim. Any shop around ~100 lum/sf seems well lit.
Not only is this technically false, it's also non-sensical.
I think that experience can accurately be called a "rule of thumb". The majority of people here aren't willing to do the work you suggest and are looking for something that works under common circumstances. As long as you don't paint your walls black, I think lum/sf is exactly what they're looking for. It worked great for me.
Completely disagree on all counts. (except the "worked great for me" part)
You're using bad information to create a rule of thumb that will mis-guide others.
Not speaking for others, but I believe the majority of the people want a good lighting job for their hard earned money, not an old wives tale. And what "work" are you talking about? It's easy to get a simple layout done.
Let me try to give you an example of why lumens per square foot doesn't work.....
You have a 1 foot by 1 foot room. You have a 100w light bulb. 100 lumens per square foot, right?
What if the ceiling was 10' high? 30' high? 50'? 500'? You'd still have 100 lumens/sq. ft. but you wouldn't have any footcandles, now would you?
What if the bulb had a lens to direct the light sideways? or up?
What if you had a lampshade? Or a diffuser?
What if the bulb was a fluorescent?
What if the bulb was an LED?
What if the ceiling was open? or silver?
What if the walls were white? Gray? Wood? Glossy? Matte?
What if the floor is carpet?
What if the room is filled with furniture or cabinets or cars or toolboxes?
What if your 100w bulb is in a strip fixture? a downlight? a highbay? a troffer? a flood light? a track head? Would that make any difference?
All of these things affect your foot candle levels. But you'd still have 100 lumens per square foot. It might be way too bright, or way too dim. But you'd still have 100 lumens per square foot.
I'm sorry for the overkill. Those are a lot of questions just to point out that you have NO idea how many of those "lumens" are getting to the target. In fact, most of the time you dont even really know how many lumens you have to start with.
Your family let you know how they feel. Just from looking at it, I'd tend to agree. My personal garage is 24x24 with a 9 foot ceiling. Very close in size to yours. I have 8 4000 lumen fixtures. Your 16 4500 lumen fixtures would blow my retinas out.
But you like yours and I like mine, so that's really the bottom line.
I'm really not trying to be a d**k, but lumens per square foot means absolutely nothing. Zero.
That's not an opinion.
CD
