[Greenbuilding] Recessed Cans in exterior ceiling - No?!

[Alan Abrams]

<I had layed out a mix of
linear fluorescent uplight and conventional PAR fixture downlights (hoping
they'll switch to CFL) which our lighting consultant poo-poo'd for the
quality of light emitted (I can't wait to hear all of the debate that this
thread spawns).>

Reflector type lamps are available both in CF and LED.  We've used r-20 and
r-30 cfl's and their output seems commensurate with incan-decadents.



< Anyway, back to the recessed cans, I'm trying to justify in
numbers why it doesn't make sense to install them.  The units proposed are
IC and air-sealed Juno fixtures going into a polyurethane spray foamed 2x10
ceiling.  The R-value of the ceiling without lights is R-50 and I'm
imagining the portion over the lights will be about R-10 (1-3/4" thick of
R-6/inch insulation).>

I just read in the latest issue of JLC that you can't shoot sprayed-in-place
foam directly against a recessed can--even an IC.  Don't know what spec this
derives from--probably the manfr--we've (reluctantly) installed IC cans in
inspected and approved foam insulated ceilings before--wonder if I should go
back and tear them out--one installation is nearly four years old....

-Alan Abrams