davies@sp20.csrd.uiuc.edu (James R. B. Davies) (04/06/90)
In article <14306@lambda.UUCP>, jlg@lambda.UUCP (Jim Giles) writes: |> In article <1990Apr4.174234.24288@tc.fluke.COM> inc@tc.fluke.COM (Gary Benson) writes: |> >My mom believes: |> > |> > It costs more to turn lights off and on than to leave them turned on |> > (regardless of the ratio of on to off time). |> |> This is true for florescent lights. It requires an average of several |> minutes worth of electricity to 'power-up' a florescent light. So, if |> you're not planning to leave it off for a larger time that that, leave |> it on. Incandescent bulbs should be turned off when they're not in use |> no matter how short the interval till the are needed next. |> |> J. Giles This is an old enough belief that it probably qualifies as folklore (although the version I've heard usually says "several hours" rather than "several minutes"). Being a skeptical sort, I decide a few years ago to try to find out if this was really true, or if it was just passed on from generation to generation while the relevant technology advanced beyond this state. So, a few years ago I did some research. While I don't remember too many specifics, the gist of it was that modern rapid-start bulbs don't really use huge amounts of power on startup. But, older designs (which apparently aren't used much any more) had a "preheat" design which used a heating element which would suck down large amounts of electricity for a few seconds to get the bulb going. Therefore, I concluded that this was indeed Urban Folklore, and that I shouldn't leave my lights on all the time after all! There was one advantage to leaving the bulbs on - the lifetime of the rapid-start bulbs (like incadescent bulbs) is partly a function of how many times they are turned on and off. So, turning off the lights might shorten the bulb life even if it doesn't use much more energy.
sv@hsv3.UUCP (Steve Verity) (04/07/90)
In article <1990Apr6.143018.24167@ux1.cso.uiuc.edu> davies@uicsrd.csrd.uiuc.edu writes: >There was one advantage to leaving the bulbs on - the lifetime of the >rapid-start bulbs (like incadescent bulbs) is partly a function of >how many times they are turned on and off. So, turning off the lights >might shorten the bulb life even if it doesn't use much more energy. My wife and I bought some 5 year light bulbs from a door to door salesman 3 and a half years ago, and they are still going. Before this, I had always thought "5 year light bulbs" were an urban myth. I have also heard about automobile tires that never wear out, and panty hose that lasts for ever. -- ...........>..........>........>......>...>...>..>..>..>..>.>.>.>>>>>>>>+ . Steve Verity sv@v7fs1 + + Now where did I leave my D50? + . Video-7 / Headland Technology + ...ames!vsi1!v7fs1!sv + .. +