The Hive

Unmeasured Is Uncontrolled

I’ve cut my electricity use because I can measure exactly how much I’m using. I want to do the same for heating oil, but …

In this project, “ The Efficient Life,” Slate is seeking your best ideas for helping people use less energy at home and save money. You can read Daniel Gross’ explanation of The Efficient Life here, his article about compact fluorescent light bulbs here, his article about utility bills and peer pressure here, his passionate exhortation that you get a home energy assessment here, and his speculation about whether we should pay fuel bills in cash here. You can submit your proposal here and scan all the proposals submitted by readers so far. Over the next six weeks, readers and judges will choose a dozen finalists, the top five ideas, and a winner.

As I’ve started paying attention to my household energy use, I have noticed something strange. It is incredibly easy for me to monitor my electricity usage and nearly impossible to monitor my use of heating oil and propane. 

My monthly electricity bills tell me exactly how many kilowatt hours I used in the most recent billing period. I can go outside and look at the (dumb) meter and see how many I’ve used in the past 24 hours. The measuring device I got during my home energy assessment tells me how many kilowatts my espresso machine draws, to the decimal point. Light bulbs are stamped with a number telling how many watts they draw per hour.  So if you know how much your electricity costs (mine is 19.2 cents per kilowatt hour), even a humanities major can figure out how much he’s spending on electricity at any given time, in any given room.

This knowledge gives people both the ability and incentive to control use, because you can easily calculate the return on the investment of your time, money, or change in behavior. In my home office, for example, I removed four overhead 65-watt incandescent bulbs and replaced them with four 15-watt dimmable compact fluorescents. (Aside from the fact that they take a few seconds to reach maximum brightness, there’s no noticeable difference.) Each hour these four lights are on, then, I’m using 200 fewer watts, saving 3.84 cents in electricity. I now know that the power strip that provides juice to my computer, monitor, speakers, and printer pulls about 120 watts when they’re on, and 24 watts when they’re shut down. The upshot: If I leave the house for two hours and shut the computer down, I’ll save 3.7 cents. If I flip off the power strip every night, it’ll save about $20 a year.

The crude gauge on my heating-oil tank. Click image to expand.
My crude heating-oil gauge

But when it comes to my use of heating oil, I have no such knowledge. The (relatively new) 250-gallon tank in the basement has a gauge on top that gives a crude measure of roughly how full it is (see photo). There’s no digital technology here. The heating oil company doesn’t receive a read-out of how low it is. Instead, using its knowledge about my past usage and information about the weather, the company sends a truck out at three- to four-week intervals during the winter. So far this heating season, deliveries have ranged in size from 240 gallons in December to 116 gallons in early January (we were away much longer this Christmas than last year). Looking back through my records, it’s clear the company could have skipped one of the deliveries it made this year entirely if it knew exactly how much oil was in my tank—saving it time and money.

There’s another way in which imprecise measurement is the enemy of efficiency. I know exactly how much electricity my family used yesterday. But I have only a vague guess of how many gallons of heating oil we burned. As a result, I can’t measure how different behavioral changes would affect consumption. What would happen if I turned the heat down to 65 instead of 68? Would it save a gallon or a half a gallon? How much oil does it take to get the house from 68 to 72 in the morning? Given that heating oil costs more than $3 per gallon, small amounts can add up to significant savings.

A digital, real-time display on top the tank would seem to be the solution. Factories and other industrial installations that use large quantities of fuel get this kind of information. But homeowners like me seem to be out of luck. Am I wrong? Is there a device I could attach that would give me a digital readout of the tank’s volume and that would allow me to see how much fuel has been used in, say, the past six hours?  While we’re at it, I want a smarter gauge for the propane tank buried in the woods, which feeds the pool heater and our stove. And I want something—anything—that can tell me when the propane tank strapped to the bottom of my Weber grill is about to run out. As it stands, I can judge only by its weight.

The ability to measure the contents of fuel tanks more accurately would seem to be a big deal, and not just for weekend barbecuers. The first step toward efficiency is measurement. Am I missing something? Why are the gauges on our fuel tanks so imprecise? Are there devices I can purchase, or rig up, that would give me a clearer readout? Please let me know in the Comments section below.

Slate is seeking the best ideas for helping people use less energy at home and save money. You can submit your proposal here, see the 10 most-popular reader proposals, and scan all the proposals submitted by readers so far. At the end of March, when we choose the top ideas, I’ll commit to making changes in my use of energy. And over the course of the next year, I’ll provide progress reports on whether my efficient life is living up to its promise.