Home Lighting Audit
Submitted By: Steve Richard (swrichard@comcast.net)

Challenge
I think we installed our first CFL light bulbs in the spring of 2006. I recall putting my first bulbs on a couple lamps and a few outdoor lights. That was a good start, but I didn’t feel particularly confident about what to do next. I was full of questions. How many bulbs is enough for now? How do we decide where to focus? Should we replace bulbs before they burn out? What about floodlights and dimmable switches? Overall, what is the best approach for transitioning our home to CFL over a period of time?

Solution Details
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In the fall of 2006 we had a “Home Performance GreenUP” performed by a firm in San Francisco called Sustainable Spaces. This was basically a comprehensive audit of our home energy use and the best opportunities for savings. One of the areas that they covered was lighting and this turned out to be a turning point for us. They analyzed our lighting costs room by room, by adding up the number of lights in each room, the wattage of each bulb, and then asked us how many hours – roughly – the lights were on each day in that room. Using that information they produced a table estimating the yearly cost to light each room in the house and the potential savings of moving to CFLs (75% of the cost). With this table it was suddenly clear where to focus. For instance, one of our son’s bedrooms with one overhead bulb was costing around $5/year to light and the family room with 12 flood lights was costing around $150/year. It’s easy to switch over the bedroom, but the family room, kitchen, and other high usage areas are where the action is.

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I decided to start tackling the energy hogs like the family room, instead of just putting in a couple bulbs here and there that helped, but didn’t make a significant difference. I wanted to save some serious energy and see a real difference on our PG&E bill!

The only problem was that the family room lighting is on a dimmer and I couldn’t find dimmable CFLs at the hardware store or Home Depot. So, I went online and found many options and ended up ordering a case of dimmable floods from 1000bulbs.com for about $15 each. That might sound like a lot (12 x $15 = $180) but the analysis by Sustainable Spaces showed that I’d save a little over $500 over a five year period, so that’s actually a savings of around $300.

I’ve continued to buy CFL bulbs focusing on where the lighting costs are the highest and where there are replaceable bulbs (leaving halogen and low-voltage alone for now). We took inventory in October 2007 and found that we had installed 51 CFL bulbs around the house, but that we still have 71 non-CFL bulbs. We’re making good progress but still have a ways to go! I’ve come to think of the old bulbs as outdated and wasteful (90% of the energy they use is converted into heat, not light) and am determined to convert the whole house.

Some tips that I’ve picked up along the way:
  • It may sound obvious, but any light that’s on for multiple hours per day or long stretches of time, such as an outdoor light that’s on all night, is a prime candidate to switch.
  • For me it’s easier to order a larger quantity of bulbs on the Internet and just have them show up, but you need to make sure you buy good quality ones. Look for a brand name like Sylvania, GE, etc.
  • Take advantage of sales on CFLs at the hardware store if you hear about it. They sometimes get batches of bulbs that are subsidized by PG&E and those can be much cheaper. Home Depot in Concord has a good selection and good prices, if you can’t find what you’re looking for in town.
  • Since I’m trying to save energy, I’m content to leave bulbs burned out or empty if there is plenty of light in a room without it.
  • I fine the kids 10 cents for leaving lights on (more than 15 min after they’ve left a room) with the proceeds going to a Christmas present for our dog.
  • I think it works best to replace lights, especially canned floodlights that are on the same circuit, as a set, versus one by one.
  • Some rooms are a good candidate to install an occupancy sensor (available at Ace) that automatically turns lights out when there is no one using it.


Benefits & Payback
The lighting upgrades that we've made so far should save us in the neighborhood of $250 per year or well over $1,000 for five years (the life of the CFL light bulbs).

According to various web sites, one CFL light bulb will prevent about half a ton of greenhouse gases (CO2) from being released into the atmosphere over its 5-7 year lifetime. Since we've installed 51 bulbs so far, that would equate to 25.5 tons over the lifetime of the bulbs. Sounds like a ton (pardon the pun)! All I know is that it saves money and makes a difference.

Another benefit is that you don't have to change light bulbs as frequently, which can be a pain.

Informational Links
If you’re interested, I made a one page table that enables you to do your own room-by-room home lighting analysis, just like Sustainable Spaces did, but for free! Click here to view and print.

Sustainable Spaces
1000bulbs.com - to buy bulbs online
CFL calculator hosted by Walmart


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