There T8's Cort. Saw them at Osh too for $10.90 for 4' 2bulb shop light.
Wondering why the T5's are more expensive for the same length compared to T8's. They both have electronic ballasts.
Found this:
General Assumptions of Cost:
- T12 = lowest lamp, ballast and fixture cost
- T8 = approx. 20% more expensive than T12
- T5 = 3-4 times the cost of T8
Why is T5 the best and how does that apply?
There are several different factors that determine levels of efficiency. Quality of light measured in CRI (Colour Rendering Index), quantity of light measured in LPW (Lumens per Watt) and CU (Co-efficiency of utilization.) The numbers being used for CU are general for those used in the low level (12 feet and under) multi-residential environment so there can be fluctuations.
CRI levels: LPW levels: CU (Generally):
T12 = 62CRI T12 = 78LPW T12 = .46CU
T8 = 85CRI T8 = 92LPW T8 = .76CU
T5 = 85CRI T5 = 103LPW T5 = .90CU
Considering these general factors, it is obvious that T5 is the best. But, how much better? With all factors weighed equally, a general presumption can be made, that:
- a. T8 is 40% more efficient than T12.
- b. T5 is 51% more efficient than T12.
Yet, T5 in this environment is only 9% more efficient than T8. This would never justify the substantial increase in fixture, lamp and ballast costs.
Furthermore, if energy savings is an issue, you can often lower the light output by 9 or 10 percent in order to recover the efficiency without any real impact to the perceived light levels.
