On Mon, 23 Oct 2017 12:55:04 +0100, Dave Plowman (News) wrote:

In article ,
Johnny B Good wrote:
On Sun, 22 Oct 2017 01:28:42 +0100, John Rumm wrote:

====snip====

I found the filament style 60W equiv lamps
to be very good a true match for light output and a pretty good CRI.

That'll be on account the 806Lm lamps "Wattage" rating is based on the
more efficient American 120v 750 hour tungsten filament lamp type than
on our less efficient UK 240v 1000 hour lamp type.

It's taken quite a few years longer than promised by Cree but we're
finally seeing LED lamps with efficiencies above the best on offer of
81Lm per watt of the past five years now raised to somewhere in the
region of 120 to 130Lm per watt.

I'd think most know an LED is more efficient than tungsten. My problem
is buying one which says it is a 100 watt equivalent only to find it is
not -
and noticeably so.

If I'm happy with a particular light level/quality, that's what I want
of any replacement, since it is the primary purpose of a light. Seems to
me many think saving money is the primary purpose of a light. In which
case leave it switched off. ;-)

When CFLs first became available, the savings in running costs compared
to tungsten filament lighting was the main selling point, especially true
in locations such as hallways and landings where, for safety as much as
convenience, it would be preferable to leave those lights switched on
between dusk and bedtime.

Now that most domestic lighting is largely CFL based, if not already
upgraded to LED, the savings aspect is rather more marginal leaving the
"Instant On" characteristic of LED lamps as the main driver towards
retiring existing fleets of CFLs in favour of relamping with marginally
more efficient LEDs which use "wattage equivalency ratings" based on the
higher efficiency American tungsten filament lamp standards rather than
on the less efficient UK and European lamp standards.

The point I was making was that the 806 Lm reference would otherwise
require a 72W rated 240v 1000 hour tungsten filament lamp. It actually
works in our favour that the "60W tungsten filament" benchmark is based
on the American 120v 750 hour lamp rather than our own feeble 240v 1000
hour rated lamps.

--
Johnny B Good