Last week I finally managed to track down a minor but annoying mystery involving a slowly-rising electric bill that's haunted my household for the past year or so. The 15% - 20% bump in the overall electricity use we'd seen was especially frustrating since I've been slowly upgrading most of the appliances, light fixtures and infrastructure in our suburban New Jersey ranch home as much I could, without arousing too many complaints from my wife -- or the neighbors. In the end, finding that slow leak took a bit of sleuthing, some persistence, and a bit of dumb luck.
The process of greening our home has been a slow but steady one, paced in equal parts by the limits of our free time and money. Instead of immediately putting solar panels up (an illogical place to start in any case), all the work we've done so far has been unglamorous and nearly invisible, but should have made a significant dent in our bill. Of course nearly all of the lights which that we use more than a couple hours a week are now compact fluorescent units, with the exception of the fixtures in the hallway. Because Catherine felt that standing in a dark hallway for 1 - 2 seconds while the CF turned on was a safety hazard, we compromised and used one low-watt incandescent bulb and one extra-bright CF unit in each of our two-bulb ceiling fixtures. We've also greened up our kitchen with an EnergyStar-rated refrigerator and dishwasher. In addition to slowly phasing out transformer-based power adapters and appliances that have more than 1 W of standby power, our other efforts include replacing the 30+ year old central air conditioner with a modern SEER 14.5 unit and putting in a whole-house fan that cuts our overall ac use by a third or more.
But, shortly after the dramatic cut in summertime energy use we made with the new ac unit, our house's appetite for electricity (seasonally adjusted) refused to budge downward despite any other improvements I made, and actually began to slowly creep up over time. About the only clue I had was that the Blue Line energy monitor (see my 2006 review) I'd installed on my electric meter seemed to rarely read a draw of much less than 1 kW-hr when I was at home, despite the fact that the laptop, peripherals, and lights in my home office only suck around 350 - 400 W-hr at worst. The two things that drew my suspicion were a large chest freezer we have, and the dehumidifier that I count on to keep our normally-damp basement from turning into a commercial mold farm. I'd considered emptying the freezer and turning it off, but decided to start by turning up the dehumidifier's humidity setting and seeing what happened.
After a couple of months of running with increasingly-high humidity settings having no real impact on the electric bill, I decided to see if our aging unit's efficiency could be improved by cleaning the dust bunnies out of the evaporator fins that condensed water out of the air. Pulling off the decorative housing quickly revealed the real problem I'd been looking for over the past year. It seems that the fins were encased in a solid cake of frost.
Whether the evaporator ice-up was due to a control failure, excessive dust build up on the fins, or somebody (I won't say who) turning the humidity control too far down, it forced the dehumidifier to run 24/7 while being unable to pull any additional moisture from the air. This had escaped my attention because the quiet, remote corner of our basement that it sat in sort of masked the fact that it was running almost continuously. The problem was further hidden from view by the fact that I took it for granted that turning up the humidity control would reduce the unit's duty cycle. Now that I know better, I've unplugged the dehumidifier and defrosted it in preparation to checking the humidistat and giving its fins a good cleaning. In the interim, keeping it off-line for a couple of weeks should help verify my suspicion that it was the source of my inflated electric bill.
My blundering detective work at home should serve as a good lesson about what it's going to take to design the energy-efficient products and systems that will meet tomorrow's stringent energy efficiency standards and environmental imperatives.
While many of the gains in energy efficiency will be achieved through breakthroughs in technology, many others will be made by conscientious designers who simply pay enough attention to the whole systems they're working with. It's up to every one of us to help spot the many hidden energy sinks that can hide in plain sight behind quick-and-dirty fixes, sloppy assumptions, and tight deadlines that can let functional but inefficient designs escape our scrutiny.
Comments? Questions? Green power insights you'd like to share with your colleagues? Write me at: lhg at en-genius.net
