FAQ-Energy Efficiency Terms and Definitions

What is Lumen Output?

Lumens is a measurement of light percieved by the eye.  In effect, this is an idication of the level of brightness of a particular type of lighting. 

Lumen Output declines over time.  This means that the bulb you put in 3 years ago will not be producing the same Lumen rating as when it was installed. 

Older bulbs, especially Metal Halide lose 70% of their Lumen output in a 3 year period. 

An Inductive Fluorescent fixture on the other hand, only loses 10% of the output over the life of the system.  But here, the life is more than 10 times more than the metal halide. 

Who is Kelvin (K)?

Kelvin is used to compare the quality of indoor light to light experienced outdoors. 

In normal daylight conditions, typical Kelvin values are between 5000 and 6000. 

The BlueMax is very close to true, natural daylight as the bulbs have a Kelvin value of 5900K. 

The existing 400 watt Metal Halide fixtures likely have a value of approximately 4000. 

This alone will make the area seem much brighter than it currently is. 

What is the Color Rendering Index (CRI)-

The color rendering index (CRI) (sometimes called color rendition index), is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source. 

100 is natural daylight, so the higher the CRI index, the closer the light source is to natural light. 

Most 400 watt Metal Halide fixtures have a CRI of between 20 and 60.  Everlast Lighting manufactures The BlueMax bulbs which have a CRI rating of 93+ making it one of the closest light sources to natural light.

What is the System Life?

System life is the rated life of the system.  There are multiple systems in a lighting system. 

There is the life of the ballast and the life of the bulb.  The manufacturer rates this life typcially as hours. 

For instance, a fluorescent bulb may have a life of 34,000 hours compared to a 400 watt metal halide lamp that has a life of 18,000 hours. 

Understanding the life of the system is important in calculating how long you can expect the pay back and savings from installing a system.  Looking only at the first 1 or 2 years is not sufficient.

What are Footcandles?

Footcandles is the unit of measurement utilized to quantify the amount of light in a given area. 

It is not always the best indicator of lighting quality, but is a simple way to determine the varying levels of light in certain areas.

Understanding footcandles and existing lighting levels helps Hovey Electric determine the best application for new installation of lighting systems. 

Improving footcandle readings typically means improving lighting quality. 

Why is Lighting Quality important?

Lighting quality is determined by categorizing the type of facility and type of functions that take place under the lighting system.  Light levels play into this as different lighting levels are suggested for different types of activities. 

Most customers refer to lighting quality as saying "the lighting is much better than before" which means the new installation is much brighter than the old system.  Employees that work in these areas are typically excited about the lighting improvements in their areas.

Why do I need to understand Watts (w)?

We wrote an article titled "Watt's" a Watt?.  This article is geared toward those who haven't yet grasped the concept of energy efficiency.  Watts have a major impact on what we spend each month in our energy bills.

What is a Kilowatt hour (kwh)-

This is the unit of measurement utilized by utilities to charge you for electricity.  Reducing the amound of kwh means reducing the amount of expense related to energy. 

If you didn't read the article above, our article titled "Watt's" a Watt? explains fully how kwh is calculated. 

Energy Safety Needs Analysis-

This is the process used by Hovey Electric to perform an energy audit of a facility. 

We refer to energy safety because we often run into safety issues that could potentially have an impact on employees or others who frequent an area. 

We are looking for your electrical systems primarily, but while we are looking we are also performing a scan to prevent any future problems or complications from your electrical system. 

This preventative approach can save you heartache down the road if you didn't even realize you have a problem. 

What is the Energy and Policy Act of 2005 (EPAct)-

The Energy and Policy Act of 2005 was established by the Federal Government to encourage investment into energy efficiency.  It was originally passed as legislation in 2005, but was renewed in 2008 as part of the Stimulus bill enacted by President Obama.

This policy allows the owner who made improvements to essentially accelerate the depreciation for the year the improvements were made. 

The Act provides incentive on a per square foot basis for energy efficiency upgrades to any of the following categories:

1. Electrical (Lighting, Motor Efficiency)
2. HVAC (Heating, Air, Ventilation)
3. Building Envelope (Insulation, Roofing, Windows)

The total potential deduction is $1.80 per square foot of area improved or $.60 per category indicated above.

There are certain requirements that must be met. 

There is also a sliding scale that enables part of the deduction depending on where you fall on the scale.  Determining qualification is an important part of the on site analysis as not all facilities will qualify.

The deduction only applies to interior improvements.

Why Energy Efficiency ROI important?

ROI or Return on Investment looks at what type of return you can expect if you make an investment to upgrade your facility. 

Comparing Energy Efficiency ROI to that of a bank account, certificate of deposit or stock market will clearly show how good of an investment energy efficiency is. 

Is Payback relevent to Energy Efficiency?

Payback is a look at how long it will take to get your original investment back from investing in energy efficiency. 

This is most often expressed in terms of time.  Payback can also be referred to as finding the breakeven point.

What is a Photometric Layout?

A photometric layout takes all of the information for your facility and utilizes the engineered output of a replacement fixture or new installation. 

This layout will estimate the footcandle levels in all areas being considered for re-lighting.  This will create an average which is an indication of improvement over existing systems. 

The layout takes into account ceiling height, color of walls, color of lfloor and working height.  A photometric layout is a good way to make sure you are going to achieve the lighting levels you expect. 

Here is an example of a photometric layout.