I've been buying the basic LED A series replacements for a few years now,
and what you say about heat dissipation is right.
They hate to run in a base up configuration. Anything above a 60w equivalent
will burn out lickety split when run base up. Even the 60w equivalents have
a seriously shortened life because all the heat gets trapped in the base
where the electronics are.
That said, the quality of light they produce has improved greatly over the
last few years.

Paul K. Dickman

"whit3rd" wrote in message
...
On Wednesday, August 8, 2018 at 6:02:14 AM UTC-7, raykeller wrote:

Everywhere in the world is converting to LED bulbs. LED bulbs are longer
lasting and more fuel efficient. However, the US light bulb
manufacturers have strong aversion to LED bulbs. They probably conspire
to deliberately make or import lousy LED bulbs to buck the trend.

No, it's worse than that. Everyone wants LEDs, so they're being churned
out to fit into existing fixtures that are completely inappropriate for
LED technology.

Incandescent bulbs tolerate elevated temperatures, and radiate in 4pi
steradians.
They work on high voltage AC.
LEDs last long at low temperatures, and radiate in 2pi steradians. They
work
on low voltage DC. But, the 'LED' items in the store are intended to
screw into
incandescent bulb sockets.

So, (1) heat dissipation is poor (you can't get 3k lumen LED lighting into
this form factor)
(2) every AC-powered lamp must convert the voltage down OR must put so
many LEDs in series
that reliabilty suffers, (3) there is a host of incompatibiiities with
dimmers, lighted
switches, and RF interference being problems. For some (actually very
good)
LED lamps, a few years' use will lower the efficiency BUT you can't
replace the
dim LED; you have to buy an entire new fixture.

Probably in a decade we'll see ballast-plus-lamp systems that let you use
a DC converter
(like a ballast) with replaceable lamps, that get good illumination
coverage in
area lighting, task lighting, spot lighting, etc. The 'compatible'
screw-in LED
items won't be the best LED lighting available.