warehouse lighting

So Im trying to figure out how much my MH system is costing me a month. Its 150 MH bulb with 2 65watt actinics. Its on for 11 hours day. I live in Omaha NE so i dont really know what to guess as far as electricity rates. Last month I used 2229 kWh and it cost me $223. Im trying to figure how much I could save a month by switching to four 21 watt LED lights. I just cant wrap my brain around all the math.

HYDRO USAGE EXAMPLE 1:  Our first example is a community arena currently using 50 400 watt Metal Halide lights.  At first glance, you would think that 50 400 watt lights would consume 20,000 watts of electricity each hour (50 x 400w = 20,000w).  This isn’t true.  

In fact, a 400 watt Metal Haide light actually consumes 452 watts, due to the ballast factor. In actuality, the 50 400 watt lights consume 22,600 watts of power each hour, or 22.6 kilowatt hours ( kWh) of hydro each hour.  With a blended hydro cost of 17¢/kWh, and operating for 4,000 hours each year, the arena currently spends $15,368 on hydro for lighting (22.6kWh x $0.17/kWh x 4000hrs = $15,368).

After producing an engineered lighting report, we recommended this client switch to two lights from the LusioFlex Essentials Series; 40 Flex ES3V-6MS and 10 Flex ES3VU-6MS lights.  The ES3V-6MS consumes only 146 watts and the ES3VU-6MS consumes 186 watts.  In total, these 50 new lights only consume a total of 7.7 kWh each hour.  The annual operating cost of this new lighting plan is only $5,236 annually.

Once this case, the new lighting will save this arena 14.7 kWh each hour – that’s a reduction of almost 66%.  Assuming the hydro rate stays at 17¢ kWh (we know it will rise, but let’s be conservative here) they’ll save $10,132 annually in hydro.

Metal halide fixtures provide indoor and outdoor illumination in many places that require wide overhead lighting such as athletic facilities, parking lots, warehouses and factories. Metal halide bulbs are valued for their high luminous efficacy (75-100 lumens/watt) and intense white light.

The upfront costs of these fixtures may be low but when maintenance and electricity costs are taken into account, the overall cost is rather high. Let’s look at the math behind calculating the operating costs.

Determine the number of actual watts used by one of your fixtures. Use the fixture wattage + wattage used by the associated ballast. Typical wattages are shown below.

175 watt fixture = 205 actual watts

250 watt fixture = 290 actual watts

400 watt fixture = 458 actual watts

1000 watt fixture = 1081 actual watts

Multiply the watts that your fixture uses by the total number of fixtures that you have to determine total watts. (single fixture watts) x (number of fixtures) = TOTAL WATTS

Example: (290 watts) x (30 fixtures) = 8700 total watts

Divide total watts (from step 2) by 1000 to determine total kilowatts. TOTAL WATTS/1000 = TOTAL KILOWATTS

Example: 8700 total watts / 1000 = 8.7 total kilowatts

Determine how many hours your lights are on per year. This doesn’t need to be exact, just a rough estimate. Start by determining how long they are on per day and then multiply number of days per year. For our example, we will use 3,000 hours per year.

Calculate kilowatt hours, which are typically used for billing units for energy delivered by electric utilities. (total kilowatts) x (hours per year) = KILOWATT HOURS

Example: 8.7 x 3,000 = 26,100 kilowatt hours

Determine the amount charged by your electric utility per kilowatt hour and calculate annual energy cost. (price per kilowatt hour) x (kilowatt hours) = ANNUAL ENERGY COST

Example: $0.09 x 26,100 = $2,349.00

Calculate how much it costs per year for each light fixture that you have. (annual energy cost) / (number of fixtures) = ANNUAL ENERGY COST PER FIXTURE

Example: $2,349.00 / 30 = $78.30

The final calculations for annual energy costs are then added to the initial cost of the light fixtures and their associated bulbs. One of the main issues with metal halide bulbs is that they tend to lose 50% of their light output half way through their typical lifespan. 

This is not the case for high pressure sodium, LED and induction alternatives. These alternatives also have longer average lifespans. They may have higher upfront costs (especially LEDs), but energy savings and lower maintenance costs realized over a period of time will offset this. Take some time to look at our lighting selection at Razorlux.com or call to speak to one of our lighting experts about your lighting needs.

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