Commercial Lighting

One of the largest users of electricity in a commercial structure is the lighting. Lighting retrofits are one of the best ways to reduce this cost in older buildings. The possibilities for such retrofits are truly almost endless. However, the specific measures that can be installed are highly dependent on the lighting demands of the commercial enterprise within the structure.

For example, in banking, only the highest quality and quantity of lighting is acceptable. Mistakes identifying counterfeit bills and entering myriads of numbers makes this a requirement. In the food related industries, color rendition is critical as food that looks off color is not appetizing. However, once business specific requirements have been identified, savings of as much as 90% in energy reduction can very often be achieved.

One immediate example of this is the replacement of incandescent Exit signs with Low Energy Demand (LED) exit signs. The incandescent fixtures use 40 watts each while the LED fixture uses only 1.5 watts each: a savings of 38.5 watts per fixture replaced. One sign alone can save about $15-20 annually on electricity costs and can last up to 25 years without a lamp replacement, compared to less than one year for an incandescent. If all U.S. companies switched to ENERGY STAR® qualified exit signs, they would save $75 million in electricity costs.

Such savings also follow through to another commonly found lighting fixture in commercial buildings. The standard four foot long commercial fluorescent lamp has undergone major improvements in both efficiency and color rendition in the last five years. Most commercial facilities still use the old T-12 lamps. Replacing these with the newer T-8 lamps is a dollar wise decision. If this approach is partnered with regular relamping throughout the facility, savings and positive cash flow can be realized in virtually every facility regardless of size or usage pattern.

The replacement of incandescent lamps with Compact Fluorescent Lamps (CFLs) is beneficial in more ways than one. Besides the obvious benefit of reducing kilowatt usage, and thus electricity, most people do not realize that the heat given off by lights accounts for a large amount of the heat the building’s air conditioner must remove each day. The replacement of high wattage incandescent lamps with reduced wattage CFLs also reduces the air conditioning portion of your bill, too.

Each watt used by a light turns into 3.4 BTU’s of heat added to the load on the Heat, Ventilation and Air Conditioning (HVAC) system. Replacing fifty 100-Watt incandescent lamps with 20-Watt CFLs reduces the cooling load by over one ton of cooling capacity. That is one ton of capacity that is not required at new construction and does not impact the bills throughout the life of the building.

50 x 100 Watts = 5,000 Watts x 3.4 BTU’s = 17,000 BTU’s
(12,000 BTU’s = One Ton of Capacity)

50 x 20 Watts = 1,000 Watts x 3.4 BTU’s = 3,400 BTU’s

This represents 13,600 Watts saved on the electric bill each month with equal light output. If electricity is priced at 5 cents per kWh, then $180 dollars in savings goes directly to the bottom line every month. This does not even include the reduced cost in electricity from reduced demand on the HVAC system!

It is best to consult qualified lighting designers or engineers with Illumination Engineers Society (IES) training before instituting a lighting retrofit.

Finally, one of the most cost-effective ways to reduce energy consumption is to turn off lights. Three ways to accomplish this are;

  • the use of manual controls,

  • the use of an occupant sensing devices, or

  • the use of automatic lighting shutoff controls.

The use of automatic lighting shutoff controls differ from occupant sensing devices in that they turn lights off based on a pre-programmed schedule. These schedules typically allow for a warning of an impending "lights-out" as well as an occupant override to accommodate off-hours use of the building. Automatic lighting shutoff controls are cost-effective with typical paybacks from as little as 6 months up to 18 months.