Thoughts on Home Energy Conservation

Recently, a post was made on Slashdot advocating we conserve energy use in our homes. Neat idea, but sadly it was filled with nearly useless time-honored ideas. I’ll briefly go through some of them and suggest better alternatives, and point out some failed thinking in them. You can’t get there if you are heading the wrong direction, and you will take a lot longer if taking a longer route.

The first recommendation is one of the oldest: Stop using incandescents, use fluorescents. This one is based solely on the notion that the fluorescent consumes less electricity to put out the same light levels. Since it uses less it must be better, right? Maybe not.

Let us assume I swap out a 60 watt incandescent for a 10 watt fluorescent. I will pay more for that bulb, but do I allegedly get in return? Allegedly I get longer life. In the real world I’ve not seen any longer life from these. I’ve tried. A lot. I’ve spent the good dough on the “good” stuff and saw no difference in life of the bulb. Even the vaunted 10 dollar CFL supposedly lasting for 10,000 hours. If I use the bulb for just three hours per day that comes out to a bit over nine years. How many of you with these have seriously not had to replace them?
For me? Dead in a matter of months or weeks in some cases. On average I’ve had no CFls exceed my incandescents on average. Many are outlasted by incandescents. Unlike an incandescent a fluorescent is harmed by turning it on and off frequently. Bulb life will rapidly decrease. The recommendatiosn I’ve seen say that you should leave a CFL on for a minimum of 15 minutes, 30 minutes preferred, and not turn it off for periods of time under a minute or so. So if I need light for 5 minutes, and I want to maintain my bulb for as long as possible without leaving it on all the time, that 5 minutes will cost me 30 minutes of energy. There goes all my “savings”.
Given that the CFLs started coming out in about 1999 (IIRC), if you use your light three solid hours each day you should not have had to replace it. If you use it four solid hours per day you might have had to replace it recently, depending on when it went into service. How many have you replaced?

I intend to set my house up to record when each light is on and off, thus providing real world usage and data. By marking in the system which are fluorescents and incnadescents, inputting their official lifetime, and keeping track I’ll have real world data. By connecting it to my moniter and alert system I should get notified when bulbs have exceeded certain percentages of their life. What will be tricky will be the multi-bulb lamps such as on the fans.

Which reminds me, vibration is bad for CFLs. Which would explain why my ceiling fan lights go through them like politicians with tax dollars. Clearly, if ceiling fans damage CFLs to the point of their lifespan being on par with incandescents (IB for short from here out), then the lifetime energy savings is entirely false.

You see, all the calculations on how much you save using CFL vs. IB is based on the CFL actually lasting for 10,000 hours. If I were to switch one on and leave it on, it should last me about 13 months on average. I don’t have that many last more than 6-8 months, and they are off during the day. Every bulb in the house, CFL or IB is replaced at least once per year. So I am not seeing 10,000 hours of these suckers. Let us say I have my main room bulbs (those on the most) on six hours per day.

Using a 60W IB or a 13W CFL, each day costs me 2.1 cents or half a penny with the CFL. Wow, that looks large. But looks can be deceiving. Over the course of 175 days, my cost for the IB energy will be $3.68 versus 80 cents for the CFL. The problem? The price of the bulbs. The marketing behind CFL relies solely on their assertion that a CFl lasts for 10,000 hours versus 750 for IB. Yet everything I find lists the “typical” IB as lasting 1000 hours, and many places use 7000-8000 for CFL lifetimes. Sadly, some places such as Wikipedia, list a typical IB as lasting 1000 hours, but then uses the 750 figure when determining it’s lifetime costs.

The average price of a CFL is $7, or about 14X the IB. With burnout times close to each other, CFLs are much more expensive than IBs. If in order to obtain the longer life we’re promised we need to leave our lights on longer, we are getting duped hard. This rapidly eats up any savings. If you want me to use less electricty, turning lights off should not increase my costs. Period. I wonder how bad we are getting snookered.
But there is something for more damaging here

If CFLs are not savings us the money we are promised, that is alot of money going down a pit that could be better spent on real improvements. it is certainly distracting us from a real savings opportunity: task lighting.

Ultimately the problem with our current mode of thinking with regards to lighting is the “room light”. Whether it be the chandelier with half a dozen bulbs or the kitchen light with one main room bulb and one over-the-sink bulb, general lighting is inefficient for most uses. Task specific lighting, that is lighting aimed at specific areas for specific tasks, can use lower lumens (light output), thus leading directly to lower watts being consumed.

Ever been to a restaurant that had a lamp directly over the table, one in the entrance, and lights over any food/employee work areas? That is an example of task lighting. Now, if they turned off the lights at unused tables they’d reap even more savings (not to mention provide a good idea how many tables are in use at a mere glance). So take that idea home with you.

Instead of the global kitchen/dining light being provided by multiple high-lumen bulbs aimed nowhere and everywhere, place a couple low lumen (say 200-500) bulbs over the food prep area. One 300 lumen bulb over the sink, and one over the stove. Instead of a five light chandelier over the dining room table, a pair of 400 lumen for long tables, or a single 800 lumen bulb for short ones should do just fine.

And use a dimmer wherever possible. Depending on the time of year, gradually increasing an IB’s brightness (yes I know some CFLs can be dimmed, but they are more expensive yet) as it gets dark out is much more energy efficient than turning a bulb on full power at the slightest hint of shade.

Other changes are important yet pose problems with CFLs. It is becoming popular (thankfully) to use motion sensors for automatic light control. Given that the more you switch a CFl the shorter it’s life gets, this would be a particularly costly combination. Yet it can easily be that a dimmer and motion sensor on an IB can save more energy than switching to CFLs.


It may appear to a casual reader I am arguing against using CFLs at all. I am not. What I am doing is pointing out how the blanket “switch to flourescent” is not a problem solver in general, and can lead to long term negative effects. CLFs can be a saver if you replace bulbs that are on for long periods of time uninterrupted, and on for at least half an hour, in the proper environmental conditions (not too hot, not too cold), in areas without vibration, and as long as they are off for at least a minute (i.e. do NOT put them in the bathroom, or on the ceiling fan). Essentially, current CFL bulbs want you to think in terms of leaving them on for maximum savings, in contrast to IB which want you to think in terms of turning them off.

Switching to task lighting, which requires less lumens, has the potential for saving more money than fluorescents. A 60W IB on for five minutes then off for another 25 uses less energy than a13W CFL that should be left on for 30 minutes to actually get the extended life we are promised. That means that most task lighting should not be using CFLs. One big advantage to requiring lower lumens is that either CFL or IB benefit from the lower demand.
I did not talk about the health benefits of IB over standard CFLs; yes they exist. These, too need to be considered in the overall picture. Well I intended to cover some other aspects of that post, but will have to do so in another post.


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