It’s time to step into the light!
We all use lights quite a lot. They are almost miraculous in how they enhance the quality of our lives and our ability to be productive, particularly in winter. All light bulbs generate convert electricity to light. The way that this conversion is done however, has a massive impact on how much electricity they consume, and how much they cost you.
Here’s an all up energy consumption comparison between the three main types of bulb: incandescent (bad), CFL (a stop gap until LEDs came along) and LED (good).
Thomas Edison invented the incandescent light bulb nearly 120 years ago, and it still works pretty much as it did then. Inside a glass bulb, electricity heats up a wire filament, causing it to glow and give off light. The problem is that more than 90% of the energy produced by incandescent lights is heat, not light. That’s 900% more electricity being consumed than necessary, that you’re paying for. In fact, Incandescent light bulbs are now deemed to be so wasteful, that their sale is now illegal (
2012<http://www.irishexaminer.com/ireland/lights-out-for-old-style-edison-bulb-on-saturday-205700.html> ) in Ireland and across the EU as of September 2012.
As an added bonus, because LED lights don’t generate any heat, they last way, way longer than Incandescents:
If you have them in your house, they are sitting there draining your finances and it’s time to move to LEDs. We already know how to calculate the payback of an energy investment. That is to say, how long it will take to pay for itself before making us money, and exactly how much money it will make us in the future. The calculation
Calculating the Energy Saving:
Watching my energy monitor, I started replacing incandescent GU10 light bulbs in a light rig in my kitchen one by one to measure the reduction in consumption. Each incandescent consumed just under 41 watts. Each LED consumes 4.5 watts. There are four bulbs in the rig, so after fitting the LEDs: 163 watts reduced to 18 watts. That’s a 145 watt reduction. These lights are on for about 1.5 hours per day –> 145 watts * 2 light rigs * 1.5 hours a day = 435 Watt hours per day. 435 *365 days a year = 158,775 /1000 = 158.775 kWk per year. To quickly work out the emissions savings: Ireland’s CO2 intensity is 535g CO2 per kWh. .535 * 159 = 85.065 kg CO2. Changing 8 light bulbs in my kitchen will avert 85kg of CO2 a year.
Calculating the Payback:
So all in, that’s a saving of 159 kWh per year. At the electricity price of €.17 / kWh, that means a financial saving of€27.01 per year. The 8 LEDs cost €22, so the payback is €22 / €27.01 = 0.81 years. So they pay for themselves in under a year.
I repeated this for the whole house, and the savings come to 495.165 kWh per year | €87.29 per year | 274.8697 Kg CO2 per year. Time to complete the change: 2 hours to shop for the LED bulbs on DX.com and 2 hours to replace all the bulbs in the house while watching the energy consumption drop on the energy monitor.
I installed the LEDs four months ago and they reduced our monthly electricity spend by about $10 a month, bringing the spend to about €610 a year from €640. Now we have our first dint in our original energy spending. It’s a long way to spending nothing on energy a year, but at last we have some progress in the form of €30 extra a year to spend on anything we want:
What LEDs should I buy?
Wait, won’t LEDs make my house look like an operating theatre? No! LEDs are available in the full colour spectrum. You can simply decide on the temperature of the colour of light you want, and buy that bulb:
Here’s the full range:
So this completes step 2 of our journey to energy freedom – cutting all energy costs from our lives.