CFL research: most efficient CFLs per dollar and watt

In doing some reaseach on 1000bulbs.com, I made an Excel spreadsheet to calculate some simple stats; lumens per watt and lumens per dollar of some popular CFLs in the daylight range. Where 6400-6500K bulbs were not available, 5000K were used. I included the higher watt bulbs initially, but I sorted the list by lumens per watt and trimmed the lower half, eliminating the least efficient bulbs, which were the higher watt ones (65+watt). Unaccounted for is the effect of the number of ballasts. Here's the data:

Forgot to mention, prices used are individual prices. Quantity discounts apply and are not factored in (since total output needs vary). This is a rough guide to efficiency and of course, other variables may apply.

Hmm But if You Buy A Bigger On You Dont Have 2 Buy as Many Splitters

Here are the stats for CFLs in the 2700K range:



When lumen output among CFLs of the same wattage was the same, the cheapest one was used. Some price figures are from 4 packs, so I took the price and divided by 4 to get the figures you see.

And yes, I suppose the cost of additional splitters could be a factor, as well as the effect of the inverse square law which works in favor of the lower wattage bulbs, at least in terms of being able to increase spacing between bulb and plant.

Has anyone used the odd-shaped 30watt 6500k bulbs? This is the first I've seen of them...

But all those figures vary from model to model and manufacturer to manufacturer. One brand 30w may be the most effiecient, another brand it may be 23 w and another 42w.

Your chart is only valid for the specific bulbs you used to look them up.

OregonMeds said:

But all those figures vary from model to model and manufacturer to manufacturer. One brand 30w may be the most effiecient, another brand it may be 23 w and another 42w.

Your chart is only valid for the specific bulbs you used to look them up.

Click to expand...

Yup. I know lots of folks here use that particular site to buy bulbs so I just thought I'd share my findings. Between wattage, lumen output, and price one should be able to determine exactly which bulbs I used in the table.