Energy Efficiency Lighting Upgrade

As we learned from the video on last page, making an energy efficient lighting upgrade involves a number of considerations: lighting efficiency (lumens/watt), light output (lumens or footcandle), light quality (color temperature and CRI), frequency of use, and use of dimmers, etc. In addition, we have to do the math!


Yes, for businesses to make a change, they have to consider the capital investment (initial cost of purchasing the new bulbs or installation cost if any), the annual savings, the pay-back (how long it takes the annual savings to offset the capital investment) and return on investment (ROI). For business in general, they are not interested in any investment or proposal that has a payback of more than one year! In this section, we will discuss most common and widely applicable P2 opportunities in lighting and how to conduct a financial analysis of the P2 alternative!

P2 in Lighting Opportunity #1 – Halogen to CFL or LED;

Compact fluorescent light (CFL) bulbs are a great P2 alternative for halogen in places where lights are not frequently switched on and off! In a residential home, bathroom lights are frequently turned on and off, CFLs are therefore not suitable due to premature burn out. However, in hotels, most bathroom lights are on most of the time. In this case, replacing halogen with CFLs of warm color temperature (such as 2700 K or the choiced of the hotel people) presents a great P2 opportunity! In residential bathroom, we can replace with LED light bulbs that are not going to burnout despite frequent on and off.

Hotel Bathroom vs. Residential Bathroom



Some restaurants use halogen flood light that allows for illumination of bigger areas, these lights are usually on all the time when restaurants are open, therefore CFL flood lights with warm color temperature (such as 2700 K or the choice of the restaurant people) or LED flood lights are great P2 alternatives!



P2 in Lighting Opportunity #2 - CFL to LED

Many homeowners use outdoor lighting for decoration and/or security, such as shown below.

Many commerical buildings also use large amount of ourdoor lightings for security and/or decoration/attraction. Because outdoor lights are usually left on for a long period of time, using CFLs or LEDs in these fixtures will save a lot of energy. However, LEDs work better particularly for the following conditions:

1) In the cold climate where CFL bulbs take a long time to get to its full brightness.

2) Lights are on and off frequently, such as used with motion sensor for security reasons. LEDs will not have the premature burnout as CFLs will.

3) Lights are in places hard to reach, the extreme long life of LEDs will save significant labor cost in changing those bulbs in hard to reach places.

However, we need to be careful of light pollution concern of the cool-white LEDs. We need to make sure LEDs are fully shielded and not close to any astronomial observatories.

Light fixture vs. Bulbs or Bulbs per fixture

Before we get into financial analysis of lighting upgrade, let's clarify on a couple of terms: light fixture, bulbs or bulbs per fixture. A light fixture is an electrical device used to create artificial light and/or illumination, by use of one or more electric bulbs. For example, in the bathroom below, there are 2 light fixtures with 3 bulbs per fixture.


In the living room shown below, there is only one light fixture with 9 bulbs per fixture.