2016-11-14

Our New Lighting Strategy Saves Us 70% on Electricity Costs

I'm responsible for managing the energy use at my condominium complex. 

My mission is to always minimize our energy costs to in order to help keep our association fees low.   By strategically using LED lighting, we have been able to reduce our lighting costs by 70%.

Details

We have a bunch of common area lighting that, for safety reasons, needs to be on 24 hours a day.

However, our lighting doesn't have to be super-bright.  It needs to be strong enough so that people can safely use the common areas, and safely enter and exit the building.

Over the past decade we have used 14 watt CFLs in all of our fixtures.   With a 25,000 hour service life, each CFL bulb lasted about 3 years (there are about 8750 hours in a year).    Some CFLs died sooner, and some lasted much longer, but given that the bulbs are lit 24 hours a day, they don't see the stress of being switched on and off.

But even with CFLs, we were still spending about $3000 a year on electric power (or $250 a month).  So I aimed to cut that electricity cost.

The Strategy

In my own unit I was using a 6 watt LED for a desk lamp, and I thought it was pretty darn bright.  And the 14 watt bulbs we were using in condominium's common areas were very bright.  So that got me thinking: could we replace the 14 watt CFL bulbs with lower brightness bulbs?

That idea helped me build a strategy:  Figure out what the right bulb is, instead of just slapping any cheap or available bulb into a fixture. 
  1. Determine the lowest brightness you need for each area.
  2. Find the lowest wattage brand-name bulb that meets or exceeds that brightness.
  3. Watch the electricity costs go down.
So we did some research to determine what brightness bulb would be sufficient. We bought a few sample bulbs from various manufacturers and tried some out.  We started with the lowest watt bulbs we could find.

The lowest wattage we could find - 3 watt bulbs - looked great in areas with multiple fixtures, but were too dim in areas served by only one fixture.  The next step up - 5 watt bulbs - were definitely good in all areas.

After testing out these bulbs in a couple zones for over a year, and without any failures, we ended up buying a bunch of bulbs and changed out our CFLs.  We replaced 70% of our 14 watt CFLs with 5 watt LEDs, the remaining 30% were replaced with 3 watt LEDs.  On average, that's 4.4 watt per bulb, or about a 70% reduction in power costs.

So far, after a year of full service, no LEDs have failed, so I do expect we'll get something close to the 50,000 hour lifespan - that's about 6 years.  That's great from a maintenance point of view.

As a bonus, our lighting is now of a consistent quality and color.  It no longer looks like we just slap up any bulb regardless of brightness or color into a fixture.   We've only heard positive comments from residents. 

What did we do with all those used, but working CFLs?  They were still working, so we didn't want to throw them away.  So instead, we offered them "for free" to the members of the condo association for use in their own units.

So what does that all mean at the end of the day?    It means that our monthly electric bill has gone down a lot.  We were running at about $3000 a year.  Now we spend less than $1000 a year.  That's $2000 saved every year, or $20,000 over 10 years.

Pros:
  • Electricity costs reduced by 70%
  • Bulb replacement costs reduced by 50%

Cons:
  • None so far

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