This is the fourth blog post in the series to calculate the total Return on Investment (ROI) that a business will generate from an LED lighting retrofit project. Previously, we published the following posts in this series:
This post will address how a lighting retrofit project will save you money on your HVAC costs. The primary assumption behind this part of the overall savings is that the retrofit project is being done in an area that is air conditioned.
So, how would a retrofit project help generate HVAC savings? Incandescent and halogen bulbs from older light fixtures do two things really well, produce light (which is what they are supposed to do) and produce a LOT of heat. Dealing with that extra heat in the summer months is what takes extra energy. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) has established a rule of thumb that it takes 30-35 watts of cooling to offset the heat generated for each 100 watts of lights within a space. We will use 32.5 watts for our computation below.
We will continue our example from the last post in that we are replacing 90 watt PAR 38 bulbs with 14 watt LED PAR 38 bulbs that operate 3,000 hours per year.
These step-by-step instructions will help your business calculate the potential HVAC savings so you can evaluate if it makes sense to include these savings in your overall ROI computation.
Step 1: Gather Data – the following information will be needed to start the calculations:
Step 2: Energy savings from reduced HVAC:
Step 3: Cost savings from reduced HVAC demand:
While a savings of $3.45 per light per year may not seem like much, if you have hundreds, or even thousands of light fixtures that you are replacing during an LED lighting retrofit project, the savings will add up quickly.
If you are considering an LED retrofit project and want to consult with a professional lighting installation company, contact PKK Lighting. We can help you evaluate the opportunity, manage the project, and maintain the lighting system well into the future.