I'm getting ready to buy the fixtures and bulbs... since I made the original post, I've hung 3 kayaks on the ceiling, above the 2 garage doors. This, plus the garage door brackets limit what I can put in the first half.
Here's what I've come up with:
- 4x 8 foot (running perpendicular at the back half)
- 9x 4 foot
If you stick with four-foot (twin tube) fixtures throughout, you will gain significant flexibility in terms of both placement AND (especially) switching. For a space as small as yours, you won't "save" enough installation cost/complexity by using eight-foot tandems to make it worth sacrificing that flexibility, IMCO. You can always **** two four-foot fixtures together to effectively form an eight-foot tandem, if/when appropriate.
The first half above the garage doors is basically my only option there, which is fine since I will only have to work back there maybe 15% of the time (should I bother putting theses on their own switch?).
Surely there must be SOME way to move the "outer" fixtures closer to the walls, so that they will not be completely blocked (hence, useless) by the (open) doors?
How does the front half look? Too much light, not enough? Should I leave the 3x 4 footers out and just start with the 4x 8 foot fixtures to see what that gets me?
Which "half" are you calling the "front"? By my usual dictionary, that would be the area nearest the overhead doors, which we just discussed. But I'm gathering from context that you REALLY mean the "back" half of the garage. In which case...
I would make the three free-standing 4-foot fixtures in the middle of the space (i.e., adjacent to your "20' 8"" notation) part (a continuation, really) of the aforementioned runs on each side of the overhead doors. This will probably in effect move them somewhat closer to those "overhead door" end of the garage; but that's OK.
The two "crossways" runs are more-or-less OK, except that I'd make them up from all four-foot fixtures, mostly for switching flexibility. The rear-most one should be kept approximately 2-3 feet off the wall, so as to do an adequate job of lighting up the cabinets, shelving, etc., ON that wall. In turn, I
might move the the other crossways run a bit closer to the overhead doors than you are currently showing.
The three "fore/aft" fixtures BETWEEN those two crossways runs are probably not needed.
I did the lumens/sq foot calculation...
And you were shocked by how high it came out, right? That's one of the reasons you want to use four-foot fixtures, exclusively, so you can better manage how much light (and how much electricity) you're using at any given moment.
This is also a very pertinent object lessone for ANYONE with a relatively low garage ceiling: By the time you get the lights laid out to provide passably even coverage, you're inevitably going to have WAY more than "enough" light, en toto.
I think I'll start with this plan but remove the 2 8 foot fixtures at the back for now.
That would be a mistake.
As mentioned above, you NEED that crossways run in order to light up the cabinets, shelving, etc., ON that wall.
This puts me between 150-200 lumens per foot with 28 bulbs. 34 bulbs puts me well over 200 lumens/foot.
I may be misunderstanding your diagram; but I think your tube count is "off".
Assuming each of the three "fore/aft" runs adjacent to the overhead doors are comprised of six tubes (i.e. three four-foot fixtures, spaced fairly closely end-to-end, but NOT butted tight together), that's 18 tubes total.
Each of the two "crossways" runs would presumably comprise 8 tubes (i.e., four four-foot fixtures, which WOULD be butted tight to each other, end-to-end); so that's another 16 tubes, bringing the total (so far) to 34.
IF you keep the three free-standing "fore/aft" fixtures near the rear of the space (which, as mentioned, I really don't think you need, but...), that's another six tubes, for a grand total of 40.
Edit. Just realized I can just do continuous 8 foot runs. So to start I will do 3 rows of two 8 foots in tandem. I can add some 4 foots perpendicular later if needed.
I'm really not sure what you're driving at here. But no matter how I try to parse that paragraph, it comes out as "undesirable", compared to what I described above.
