Let me be very clear. This is an article about saving money. It is a cost analysis of alternative lighting options for the home. This is not an article about morality, social responsibility, climate change, natural or man-made global warming, or whether or not Al Gore invented pants! I am passing no judgments on you nor anyone else based on what you choose to use. Got it? Good. Let’s begin…

I’m not going to mention the obvious actions of cutting off unused lights and appliances and messing with your thermostat to save on energy. Let’s look at how the technology of lighting options can help reduce your energy costs.

CFLs and LEDs: Compact Florescent Lights and Light Emitting Diodes. OK, these are a little obvious for cutting back on energy, but do they save you money when you consider their higher costs? That’s a more difficult question to answer because you have to factor in the following variables:

Buy in price: How much does the bulb cost compared to the incandescent bulbs?

Expected life: How long should you expect the bulb to last before it dies?

Energy use: How much energy will it consume in a given time period (watts)?

Subsidies: Are there government subsidies or tax breaks for these where you live?

Energy cost: How much does your energy use cost you?

Disposal cost: Remember, CFLs are considered hazardous materials because they contain mercury vapor and must be disposed of properly.

We need to run these numbers for all of your lighting options and get a cost per time period so we can compare apples to apples.

I’m going to make up some acronyms to shorten our formula below:

pp = Purchase Price

ppk = Price Per kWh

blbh = Bulb Lifetime Burn Hours

dc = Disposal Cost

s = subsidies

We’ll use this formula to give us cost per hour:

(pp + (ppk * blbh) + dc — s) / blbh

Keep in mind, there’s not just one answer to this, and this month’s answer could very well be different from next month’s answer considering lighting prices and energy prices are always changing. Plus, if you have coupons or your local store has sales, that will factor in as well. Also, geographic location and legal jurisdictions impact the cost as these variables are different all over the world. It might be more cost effective in say, Los Angeles, CA than in, say, Chattanooga, TN.

Here’s how to figure the more complicated variables before you plug them into the formula.

Energy use pricing is a little complicated, so here’s how you figure that value. Get your most recent electric bill. If it doesn’t directly state the cost per kilowatt hour (kWh), then it should at least tell you how many kilowatt hours you’ve used. It may not even be labeled as kWh and may be simply something like “Amount Used,” like on my electric bill. Once you find that, get the total on your bill for just energy use. Some bills are broken down by electricity used, maybe a fuel surcharge, maybe some taxes and fees. Any line items that are constant and not changing based on your energy usage, don’t count those. Anything related to your energy usage, add it all up. Then, divide that cost by total kWh used. That’s your cost per kWh. If you calculated correctly, it should be around \$0.04 to \$0.10 or so, at least in the United States. Here’s a link that’ll give you a ballpark figure by US state.