Case 1

Operation time every month roughly based on:

1. Building #1: 21 regular days which run 15hrs/day, 4 Sundays which run about 10 hrs/day; so the total lighting hours for one month is 15x21+4x10=355hrs;
2. Building#2: 21 regular days one month, which run 14hrs/day; do not count Sunday and OT. So total lighting hours for one month is 14x21=294hrs; If Building#2 run more time, we will save more electricity.

Do not count OT and night lights which run 24hrs/day. If count it, we will save more. Running more, saving more.

There are total 259 lights in Building #1; 235pcs 400W MH lights, and 24pcs 250 W MH lights and 128 lights in Building#2. We will replace 400W MH lights with 150W LED lights, and replace 250W MH lights with 120W LED lights.

Calculation show below:

For old MH lights:

1. Building#1: 235x 0.4kwx355hrs+24x0.25kwx355hrs=33370+2130=35500kwh;
2. Building#2: 128x0.4kwx294hrs=15052kwh;

For current MH lights, electricity consumption roughly one month:

(35500kwh+15052kwh) x $0.09=$4549.68/month

For LED lights:

1. Building#1: 235x 0.15kwx 355hrs+24x 0.12kwx 355hrs=12513+1022=13535kwh;
2. Building#2: We will use motion sensor to control 80% lights. Suppose 80% lights only use 50% time;

128x 294hrsx 0.15kw=5644kwh;

128x 80%x 294hrsx 1/2x 0.15kw=2257kwh;

For LED lights, electricity consumption roughly one month:

(13535+3387) x $0.09=$1522.98;

Electricity saving for one month: $4549.68-$1522.98=$3026.7/month;

Electricity saving for one year: $3026.7x 12=$36320.4;