Thursday, November 8, 2012

Christmas LED Discount!

Just a quick post to point to Home Depot's annual recycling discount for Christmas LEDs (see also their YouTube promo) that lasts 7 more days. Turn in an old (even broken!) string of incandescent Christmas lights and you'll receive a coupon for $3 to $5 off of a new set of LEDs! The days are ticking by, and this discount lasts only through November 14, 2012.

I must say that the prices have not fallen this year, so the payback times for replacing strings (as discussed in last year's Christmas LED Special post) are still relatively long. As pointed out, the payback time for replacing strings after taking the above discount into account is around 8 years.

Recycle Now!

And if you just want to empty your closet or attic of clutter, this is a great time and place to recycle your old strings--even if you don't need the discount coupon at this time. It's not easy finding a place to recycle old Christmas lights in June. In fact, this may be one of your only chances to do so all year long. So just roll up any old strings and drop them off at Home Depot for recycling. (Other hardware stores may also recycle these strings this time of year.)

The question of C9s

We have never been big into the (big) C9 roof and yard lights, so the replacements I considered in the prior post related strictly to the mini-Christmas lights. So when I got an ad in the mail from Ace Hardware claiming a $514.35 savings for 300 C9 LED bulbs over 10 years, I thought I would give them a reality check.

The Energy Cost of Old C9s

The old-style incandescent C9s are typically 7 Watt bulbs (though 10 Watt extra bright bulbs are available). That's a lot of wattage when multiplied by 300 bulbs (= 2,100 Watts), and the cost per season (using my $1/Watt rule of thumb) is not inconsequential:
7W x 42days/365 x 6hours/24 = $0.20/bulb x 300 bulbs = $60/year
Over 10 years, the cost of old incandescents is then $600, so the energy savings by switching to comparable LEDs is 80% to 90% of that cost. So, yes, the Ace Hardware claim is believable.

 What are Comparable C9 LEDs?

I asked Google: "are C9 LEDs as bright as incandescents?" and found a useful answer at HolidayLEDs. Basically, some are and some aren't. The replacement bulbs they sell have 5 LEDs per bulb, use 0.96W (= 14% of the 7W bulbs they replace), and are brighter. But the C9 strings they sell have only 1 LED per bulb and use only 0.072W per bulb (= 1% as compared to 7W bulbs) and are dimmer. 

Basically, LEDs are great and can reasonably be expected to save 80% to 90% of energy to produce the same amount of light--but NOT a savings of 99%. They're good, but not miracle workers! More technically, the efficacy of incandescents is on the order of 10 to 15 lumens/Watt, while LEDs currently top out at over 100 lumens/Watt; so an LED needs about 10% to 15% as much energy to produce the same amount of light as an incandescent.

So when Home Depot sells replacement bulbs with 3 LEDs running at 0.45W (= 6.4% of 7W), one can suspect they may be a bit dimmer than the old bulbs, but a 100 light string running only 8.4W (= 1.2% of 700W) must be much dimmer.

Ace Hardware's ad claiming a 91% energy savings for their C9 strings just might indicate that their LED strings are comparable in brightness to incandescent strings.

To be sure, not all LEDs are created equal. Be ready to do some homework and quite possibly some testing to find satisfactory strings. And look for the Energy Star label as one indicator of vetted quality.

I would be grateful for any data and experience others might provide regarding replacing C9s.

The one who says he is in the light but hates his brother is in the darkness until now. (1 John 2:9)

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