# Conservation Pays More With Inflation

99 Posts
Mar 11, 2011 06:48 pm
Conservation Pays More With Inflation

When people start researching alternative energy and efficiency, they either start out with the intention of reducing their future utility costs, or in the process, they try to determine the "pay-back" from installing particular technologies.  Either way, the lifetime energy savings and up-front cost are invariably punched into a calculator to try to figure out whether what one is contemplating purchasing is "worth it".  However, rarely do people factor in inflation!

Let's face it, doing compound inflation calculations is not easy, so it's easy to neglect it.  And how much of a role can inflation play anyway?  Turns out, quite a bit.  The power of compounding is significant.  At only 3% inflation, prices double in 24 years -- about the rated lifespan of a photovoltaic panel.  If inflation goes into the double-digits again like in the 1970s and early '80s, which is rather likely with the Fed's "quantitative easing", then prices can double in under 5-7 years.  Wouldn't doubly expensive electricity be a powerful component in any calculation of "pay-back" from an initial investment today?  I would say yes.

I decided to apply this train of thought to the relative efficiency and costs of various types of light bulbs.  I created an interactive calculator where you can plug in your current cost of electricity, the number of light fixtures you have, how many hours those fixtures are on per day on average, and what you think the inflation rate might go to.  The calculator will show you how much it will cost you based on which kind of light bulb you use -- incandescent, ESL, CFL, or LED.

Think incandescent bulbs are cheap at only 60 cents each?  Don't want to spring for an \$18 40-Watt equivalent LED?  At only 2% inflation, the "cheap" incandescent bulbs will actually cost you \$19.53 over the lifespan of the LED.  At 10% inflation, the "cheap" bulbs will cost \$66!  That's pretty significant.  But if you think that's interesting, check out what the difference in electricity costs will be!

Click here to try it out with your own assumptions.  Feel free to share the link with any friends or family who still buy the "cheap" bulbs.

49 Posts
Mar 11, 2011 10:47 pm
Re: Conservation Pays More With Inflation

Ok I see your point, but the difference in the bank from the 19.53 and the 18 could be saved and earned interest on.
Also what will the 10 years from now yield in the cost lowering for led bulbs and the improvements?

99 Posts
Mar 12, 2011 05:57 am
Re: Conservation Pays More With Inflation

Well that's with very conservative inflation assumptions.  Plug in 5, 10, 15%.  And that's just the bulb cost, not including the electricity difference.  Look at what the total difference in cost is with electricity included!  The point with the 18 and 19.53 was that even the bulb cost alone is comparable.  You can't just look at a high up-front cost and think that it's expensive, because considering the lifespan and efficiency, it's actually cheaper.

49 Posts
Mar 12, 2011 08:45 am
Re: Conservation Pays More With Inflation

Thanks, I was actually looking at these basement led lights for my off-grid cabin up north to mount in a hanging ceiling.
http://ledceilingtile.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=LED&Category_Code=PI
I have tried the led lights in the bedrooms that screw in like a light bulb equal to 60 watts.  They were way to dull encased in the glass, even dimmer than the new cfl bulbs. I want them for my cabin because it is off grid. Let me know if anyone has opinions or tried these kinds of led"s.

99 Posts
Mar 14, 2011 06:27 pm
Re: Conservation Pays More With Inflation

You need to look at the "lumens" of output, not the watts.  A 40W incandescent bulb puts out 450 lumens.  If you want 40W-equivalent, make sure it produces 450 lumens.  Sometimes they will label something 40W-equivalent and it only puts out 200 lumens.  I don't know how they get away with that.  Likewise, a 60W incandescent puts out around 900 lumens, so for a 60W-equivalent, make sure your CFL or LED puts out 900 lumens.  If they don't list it, call the manufacturer and ask.

49 Posts
Mar 14, 2011 08:08 pm
Re: Conservation Pays More With Inflation

Thanks they dont list the lumens. Just the color spectrum.
Ill have to find out

462 Posts
Mar 14, 2011 11:52 pm
Re: Conservation Pays More With Inflation

James, a cheap alternative for 12 volt lighting is to use automotive bulbs such as break lights. They usually only draw around 1 amp and give off bright light. I've seen them used in marine novelty lights. The best thing is that they are cheap and readily available most anywhere, even free at junk yards.

99 Posts
Mar 15, 2011 01:56 am
Re: Conservation Pays More With Inflation

I personally use the following 12VDC bulbs for ambient lighting in my off-grid house:

MR-PL-DC-WW-12
12VDC Medium Base Bulb, Warm White
Case of 12 pcs: \$225.00 (\$18.75 ea)

The light they produce is very warm and full-spectrum and even coverage, like any 25W incandescent bulb, but these use only 3.5W each.  The daylight white ones are also very pleasing and just a little brighter.

I use them in 4" recessed cans as well as wall fixtures.  They would also work in lamps or ceiling fans just fine.  One alone is too little for anything but a tiny room (e.g. my mud room and half-bath).  Between 2-4 in a room will light it well, though you'll still want task lighting, e.g. a lamp to read by.  If you wanted the same light output as a 60W incandescent bulb (~900 lumens), you would need to use 6-7 of these 130 lumen bulbs.  That said, I think that 4 of these spread out around a room equally will produce the same effect as a single 60W point source, since the lumens reaching the far walls will be quite a bit lower from a single central source than four distributed ones.  Luminosity decreases exponentially rather than linearly with distance.  I also think multiple sources, especially a combination of up and down lights and lamps, feels nicer than a single bright one.

My lighting philosophy right now is to use 12VDC for all of my ambient lighting and to use 120VAC from an inverter for bright task lighting.  This way I'm not dependent on the inverter as a single point of failure, but I still get the benefits of AC lighting, automation, and appliances.  So if my inverter goes out, I still have lighting and other conveniences.  I have all of my 120VAC lights on an automation system so that I can turn them all off from a single switch at night or when leaving the house.  I have all of my 12VDC lights (which provide ambient lighting) on motion sensors to turn on and off automatically based on occupancy.

I like how the LEDs turn on instantly when you walk into a room whereas CFLs take time to warm up to full brightness.  This is particularly important for rooms used for short durations such as hallways and bathrooms.  Also, LEDs do not suffer from repeated cycling like CFLs and incandescents do, so using LEDs are especially useful for frequently used ambient lighting of this type.
« Last Edit: Mar 15, 2011 01:59 am by Thomas Anderson »

49 Posts
Mar 15, 2011 09:51 pm
Re: Conservation Pays More With Inflation

They say each one has 3200 lumins and you can get a dimmer.
Thank you I didn't know they were 12v which they are.  Im off grid with 110/220 volt I would have to run a separate line for the 12v.

99 Posts
Mar 16, 2011 04:28 pm
Re: Conservation Pays More With Inflation

3200 lumens is about the same as two 100W incandescent bulbs or one 48" fluorescent tube, so that's rather bright.  The dimmer might be a good idea.  I would still recommend to split your cost and lighting into more, lower-cost fixtures.  Also, if you are able, running the extra 12V line would be a good idea.  What do you have for light if your inverter fails for some reason?  Some 12VDC lights would be a good backup instead of relying entirely on your inverter.

49 Posts
Mar 17, 2011 10:31 pm
Re: Conservation Pays More With Inflation

Thank you this helps that you give examples very much.
Right now it would be flashlights and candles. I would worry more about the fridge and furnace.

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