kj wrote:
Thank you all very much for your suggestions. After looking at
diagrams of similar recessed lighting housings online I realize
that mine is apparently pretty unusual. I now see that, as a rule,
in recessed lighting fixtures the bulb goes into the socket
vertically; i.e. when one screws the bulb in, the axis of the bulb's
rotation is vertical. But that's not the way it is in my fixture.
The axis of rotation is (nearly) horizontal. (Yes, even under the
best circumstances it takes *forever* to change a lightbulb in
these fixtures.)

I guess builders use such an insanely incovenient design because
by having the bulb horizontal instead of vertical they can save
1-2 vertical inches per story. (Since this is a family ng, I will
not say what I think of such builders.)

Save your acrimony as there is absolutely no validity in your
supposition.

There has never been a builder that has determined the depth of the
floor joists by considering the height of a recessed fixture. The
fixture may be dictated by the height of the floor joists which are in
turn based on the design loads.

If the structure was sufficient, and the only reason to increase the
height of the floor was those fixtures, each recessed fixture's cost
would be figured in the thousands.

The builder/electrician chose that fixture for a reason. Whether or
not there were other options available, and whether the right decision
was made at the time, is moot.

R