Friday, April 17, 2015

No one really thinks about light bulbs until they burn out and you are sitting in the dark. This is seriously unfortunate since light sources require a significant amount of energy to run and can end up costing a lot of money. For example, this article in Carolina Country focuses on the best long term investments for light bulbs.

One of the most common light bulbs is a 60 watt incandescent bulb that generates almost more heat than light and has an expected lifespan of less than a year assuming 3 hours of use per day. After President George W. Bush signed the Energy Independence and Security Act in 2007, companies began to develop much more efficient bulbs in order to meet new federal standards. This eventually led to the widespread adoption of the compact fluorescent lamp (CFL) and light emitting diode (LED) bulbs.

A CFL bulb produces light when an electric current travels through mercury gas and argon, creates ultraviolet light, and excites a coating on the inside of the bulb. An LED bulb, on the other hand, emits light when an electric current is sent through a semiconductor. Either way, both of these methods are much less energy intensive than sending a current through a filament in an incandescent bulb.

Since these relatively newer technologies use less energy, one might expect that everyone will have replaced every fixture in their homes and businesses with either a CFL or LED bulb. In reality, such substitutions are not this simple. Similar to other energy efficient technologies, the new bulbs are more expensive up front and the savings are realized in the future. The following table about bulb costs by factoring in bulb price and electricity rates (assuming a $0.124/kWh charge) demonstrates this idea.

Bulb type1 year5 years10 years
borrowed from Alan C. Shedd and Carolina Country

As you can see, the LED and the CFL bulbs are significantly cheaper than the incandescent bulbs over a period as short as 5 years.

This, however, does not mean that you should instantly replace every incandescent bulb you can find. As long as the bulb is still working properly, there is no need to dispose of it. This would just be wasteful. Once the incandescent bulb runs out on its own, then you can choose your next appropriate bulb.

  • "Learn About CFLs." ENERGY STAR. Web. 17 Apr. 2015. <>. 
  • "Learn About LED Bulbs." ENERGY STAR. Web. 17 Apr. 2015. <>.
  • Shedd, Alan C. "Comparing the New Light Bulbs." Carolina Country. Carolina Country, 1 Mar. 2015. Web. 17 Apr. 2015. <>.

Wednesday, April 8, 2015

The cold weather finally seems to have left Chapel Hill and I think that is something that all of us can be happy about. Now that things have warmed up, it becomes very tempting to open your windows and let the nice spring breeze circulate. Although this may seem like a nice idea, letting in so much outside air can seriously affect the efficiency of your building's HVAC system.

As our website explains, air conditioning systems have to work overtime to dehumidify the air and pressurize buildings when windows or doors are unnecessarily left open. This quickly becomes a problem when people all across campus participate.

In fact, our buildings' heating and cooling systems are specifically designed to incorporate outside air when temperatures are appropriate in order to get rid of stagnant air. So do the right thing and keep your windows closed this spring no matter how nice the weather is outside.