Each purchase is different and depends upon height of ceiling, fixture hanging height, spacing, illumination requirements within work areas, voltage, money available, energy savings potential, potential energy rebates available, tax credits, improved work environment, better production from employees, lowering shipping errors due to low lighting levels and finally, who do I purchase or work with to get these fixtures. Will they provide an energy audit, help with rebates, provide installation or is that up to the buyer, and what is the timeline for everybody involved.
Many marketing representatives use radio, TV or news print ads to entice potential customers to respond and when you do, what should you be aware of? First always check out the specification sheets of the fixtures to be used and make sure that this is what you are getting unless you sign off on a change order. Use T5’S or LED’s for higher ceiling heights and T8’s or LED’s for lower ceiling heights. Many contractors or companies will try to convince you that T5’s are right for lower heights but they will give off a Angular light pattern effect at lower heights and not the spread of light without darker areas. T5’s and LED’s at higher heights, 16’ upward will greatly improve the illumination of your work plane but I would tend to stay away from these fixtures at lower heights. T8’s and LED’s with diffuser and 120+ beam angle will give you a better spread of light and you will probably be happier. What about LEDs? At lower heights, use LEDs that have a diffuser and 120 to 180 degree beam angle so that you will get the illumination of the light through the work plane. Several years ago, we experimented with T5’s verse T8’s at L3 Communications at a height of approximately 14’ and found that T5’s gave off great light but in a cone pattern with high foot candles within the spread of light but outside this cone pattern, the foot candles dropped off significantly. The T8’s foot candles under the fixture wasn’t as bright as the T5’s but it gave very even illumination.
T5’s are great for higher heights, give off great light and are probably still somewhat cheaper than most LED’s but you will still have a maintenance issue with tubes and ballasts over time. LED’s with a diffuser and 120 degree beam angle will give off great light illumination and no maintenance compared to the T5’s or T8’s. Most LED’s will have an L70 of 50,000 hours to 70,000 hours and most will have a calculated life of almost 100,000 hours.
On savings energy comparison of T5-4L fixture (216watts), T8-6L fixture with high ballast output (221watts) and a equal LED fixture (90watts), one can see the wattage difference between these three. A 400 watt metal halide can be replaced with a 120-150 watt LED fixture depending upon again the illumination need at the work plane. Now with most LED’s coming out with 110 to 115 lumens per watt and higher output drivers, you can get the improved light levels with lower wattages in most cased. Also with motion sensors and daylight harvesting on the fixtures, you can increase the energy savings automatically. Most people are looking for less maintenance and a long term solution so are turning to LED’s for the solution.
Do you own research on T5’s, T8’s and LED’s before buying? Study where you want to have improved lighting and be aware of ceiling height, fixture height, spacing, voltage, and cost of fixtures. Also consider the long term maintenance factor of changing bulbs, ballasts and the labor that it takes to complete this task. Check out our web site on various LED’s that are available.
Just be careful of what people say and do. Note that experience in the field is important and now there are many new companies with inexperience staff. Be careful, save money and reduce your maintenance.