Summer/Winter use of CFLS?

Question

I'm wondering if any formal testing has ever been done on this. 
Assuming a closed environment... (Your house isn't rally closed but it doesn't really have much effect here) 
Using a CFL versus an incandescent light bulb generates roughly the same amount of lumens but uses 70% less energy. This energy savings is primarily because the CFL generates much less heat than a incandescent bulb "normally considered wasted energy". However, it would seem to me that in the winter time, when the house is closed the heater is under the control of thermostatat, that any heat produced by lighting (or any other sources) would effect the ambient temperature and have a diminishing effect on the heaters run time. The only variable is the efficenacy of the heater vs the efficieny of the bulb. Conversely incandescent lights run in the summer when the air is on whould have the opposite effect because the air conditioning has to extract that excess heat created by the bulb. 

Just doing the math in my head whithout any lab testing, I would estimate that the use of a CFL in place of a incandescent light whish diminishes electricity useage of the bulb itself by 70% is actually saving you something close to 70% when no climate control is being utilized. 0-10% when in a heated climate, and somewhere near 250% when it is in an air-conditioned climate. Are there any tests out there that show how close my numbers are?

John W · Accepted Answer

The heat produced by the lights would reduce the amount of time the heaters would run.   If the heaters were electric then there would be no savings in using CFL's over incandescent light bulbs as all the energy is eventually transformed into heat, however if the heat is from natural gas then there would be an economic savings as energy from natural gas is typically one third the price per BTU as electricity though a gas furnace is less efficient in that some heat is vented to the outside.   I doubt that the issue has been studied to any degree, lighting represents a small percentage of a home's energy use, heating, cooling and hot water is over 70% of a home's energy use.   Changing the light bulbs may benefit the utilities in an overall reduction but it doesn't benefit the home owner by much.

J. · Answer

CFLs in cold weather are worthless.  The problem lies with the ballast IC design.  They do not ignite when much below freezing.  So in a way you can save a ton of money- you just can't see anything.

LED's- which use a fraction of the CFL'e energy are usually cold capable luminares.  Most are good to at least -20 F down to -40C or F.  

I do not need formal testing to know that they do not work in cold weather.  I have an outdoor light that gets switched to incandescent when it is consistently below freezing.  

If you open up the base, there is a controller IC, plus a few other components- when you check those component datasheets from their manufacturer you find most have an operating rage above freezing.  No need for any formal test there.

So the choice is your- learn to see in the dark- and save gobs of energy with CFL's and risk falling and a need for emergency room services, or stop fooling one's self in diminishing retunrns, and put in either LED lighting, or incandescents and see things normally.

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Summer/Winter use of CFLS?

2 Answers