 | | 
|
Which
is Cheaper? A 500 watt Quartz Flood or a 150 watt High Pressure Sodium
Flood?
Which
gives more light? A 500 watt Quartz Flood or a 150 watt High Pressure
Sodium Flood?
Which
is Cheaper? A 500 watt Quartz Flood or a 150 watt High Pressure Sodium
Flood?
It's a trick question, really.
The answer is-- Although a Quartz fixture costs far less to purchase
initially, $16 compared to $77 for the High Pressure Sodium flood light,
it is actually far more costly over a 10 year period, by over 900%!
Here's a 10 Year cost comparison between a Quartz fixture and an HPS fixture
that produces equal light output
|
|
Fixture
and Wattage
|
150 watt
HPS
|
500 watt
Quartz
|
|
Light output in lumens:
|
16,000 lumens
|
10,500 lumens
|
|
Lamp Life
|
24,000 hours
|
2,000 hours
|
|
Initial Fixture Cost
|
$77
|
$16
|
|
Annual Electricity Cost @ $ .07 kwh*
|
$30
|
$300
|
|
Electricity Cost over 10 year lifetime
|
$300
|
$3000
|
|
Lamp life @ 10 hours per night
|
6.8 years
|
7 months
|
|
Lamp replacement costs for 6 years
|
$24
|
$264**
|
|
Total Lifetime Cost
|
$431 |
$3580 |
*
If the fixture is operated 10 hours per night and the local electricity
cost is $ .07 per kwh, the national average. If your area's cost are higher,
the savings for using HID lighting will be even more dramatic.
** Calculated by assuming the quartz lamp will be replaced 17.6 times during
a 10 year period at $5 per lamp and $10 labor cost. A HPS lamp will cost
$14 plus the same $10 labor cost.
Which
gives more light? A 500 watt Quartz Flood or a 150 watt High Pressure
Sodium Flood?
Another trick question.
The answer is-- Although 500 is indeed more wattage than 150, the lights
are very different in their ability to convert watts (power) into lumens
(light).
In other words, the highly efficient 150 watt HPS fixture converts watts
to lumens so efficiently that its lumen output (16,000 lumens) is about
equal to the less efficient 500 watt quartz fixture (10,500 lumens).
|
|
|
