Spiral Fluorescents or T-12's , cost and efficency question

larry_c(z6 Stl. Mo.)January 28, 2007

I just bought a 6 pack 60 watt spiral fluorescents from Home Depot for 10 bucks.

These are rated as a 60 watt equivalent..I assume that they are comparing it to a standard incandesant bulb. That incandesant was costing me $ 3.08 to run 24/7 for one month and these cost .67 per month. So the cost savings for the house fixtures is a no brainer. The 4 foot T-12 fluorescents cost $ 1.91 to run 24/7 for one month. ( FYI figures taken from Ameron US light calc cost estimator) They appear to be flat out daily cost winners.

The spiral is listed as 900 lumens, color 2700K, 14 watts, 10,000 life hrs.

The T12 (cool white) is listed as 3150 lumens, color 4100K, 40 watts, 15,000 life hours.

Spiral gets 64.28 lumens per watt while the T-12 gets 78.75 lumens per watt.

Six spirals cost $ 10. and $ 3.91/month to operate and emit 5400 Lumens.

Two T-12's cost anywhere from $ 2.50/each up to $ 6.00 and would cost $ 3.83/ month to operate and would emit 6300 lumens.

With all of that being said there isn't a large difference here except the color and the cost of the fixtures to hold the bulbs. I happen to own many clamp on fixtures from a lucky garage sale grab. So I have the power to run either.Maybe the solution is to mix em up and use both?

Thougts please.


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larry_c(z6 Stl. Mo.)

Opps..the t-12's cost $ 3.83/each or 7.66/month to operate if left on 24/7.


    Bookmark   January 28, 2007 at 6:17PM
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shrubs_n_bulbs(z8/9 UK)

The two T12s give you 17% more light (compared to six spirals), cost 2% less to run, last longer (probably twice as long), cost less to replace, and don't lose as much brightness as they get older. Why mix? If initial setup costs are higher for the T12s then you may have to run for a certain number of months before you are saving money.

I think you were right first time with the figures. Two 40W T12s would cost slightly less to almost the same as 6x14W spirals, to run for a month. Your electricity is about 8c/kWh? Nice if you can get it!

If you really care about cost-effectiveness of your lighting solution, get T8s on an electronic ballast (or even 28W T5s at 104 lumens/W, although not so easy to find and may be more expensive to setup). I get 93 lumens/W from my two 36W T8s (I actually run more than two) giving 6700 lumens, costing $3.45/month on your electricity.

    Bookmark   January 29, 2007 at 3:36PM
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