Sunday, December 08, 2013

Waste Heat

A (physicist) friend in Boulder said that incandescent light bulbs and "waste heat" get a bad rap. So what if incandescent light bulbs put off heat if you use them in the winter or at night, when your house could use the "waste" heat anyway?  Heat is not wasted if you need it.

I'm reminded of this because we are experiencing the coldest temperatures of the year (so far) without home heating.  We are awaiting a new motor and other replacement parts for our 15 year old furnace.

Our thermostat keeps track of how many total hours the furnace runs and we've been logging about 50 yours per winter.  This doesn't sound like much, but the total includes only times when the furnace cycles on.  The motor also runs the whole-house fan, which is hooked up to an electrostatic air filter.  We run that any time of the year when dust or pollution is a problem.  The motor ran for more than 50 hrs*15 years and we should have checked the system *before* we needed it.  Live and learn.

We replaced most of the incandescent light bulbs in our house with fluorescent ones.  Right now, I am really grateful for the few remaining incandescent bulbs in our home because of the welcome heat they put out.  Our indoor temps have been hovering between 55-63 F this past week while outdoor temps have dipped as low as the upper 30s.  At home, we dress like we do at night at camp.



I just love this vintage lamp my MIL gave me. I need to replace the rotted leather lacing, but it's in great shape otherwise.  I've received some fantastic mid-century pieces from Sweden and Japan from both my mom and my MIL in their recent decluttering campaigns.


  1. It's rarely that cold in California! I'm sorry about your furnace. We are having an ice storm right now, and while it looks pretty, is very dangerous. We had to cancel our tree trimming party until next Saturday. I followed your suggestion about saving hot water in the teapot and bathtub, and we installed dark tile in the foyer where the sun shines in on winter days -it keeps the entryway warmer

  2. Anonymous08:52

    Have you seen this?

    1. Yes, I have seen it, but I'm too worried about indoor air quality to try it. Besides, my home is larger than his room.

      I am pulling up the blinds--following the sun--as our grandmothers would have done for maximum solar gain. I also put countertop samples (tile, granite and quartz) on the south-facing window ledge for passive solar help.

      We replaced our CRT TV and computer for energy-saving ones so they are little use as space heaters.

      I wonder if I could run a really, really energy-intensive computation on my iMac? I could re-run my PhD research code. It will probably take just a few hours today on the iMac compared to weeks on the departmental workstation back then.

  3. In the winter it doesn't matter, but it makes double the difference in the summer in Livermore, the energy to heat the bulb and the energy to run the A/C. Not that you were arguing about that.

    It's the one size fits all attitude that gets applied to so many things that really annoys me. You know, if it's bad in this situation, then it must always be bad. Lack of critical thinking skills ... rant, rant, rant.

    1. Yup. I read a couple of decades ago that a large amount of US energy use was for a/c used to cool the heat from lighting. With CFL, that # must have gone down.

      Anyway, that is not a problem in coastal CA or high altitude CO, where night-time temps are cool and the heat from incandescent light bulbs is welcome. It would be different where you live, though.

      Why can't we have rational discussions where we are allowed to pick the optimal technology for our own specific application?

  4. What an interesting discussion. It's my first winter in ten years so i do appreciate the "extra" heat wherever I can find it. And I love the dressing for camping remark since that's how I've looked for the last month. I do love the extra light I am enjoying from the snow reflecting during the daylight today since our70 year old house is normally so very dark in these winter months.

  5. That's a really smart way of going about balancing the temperature in your house, given the limitations that you had – such as a furnace that wasn't working at the time. That being said, I hope that your furnace was successfully repaired soon after, and that you did not experience the same problem during this past winter. Take care!

    Shelley Coday @ C And C Heat


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