Ask the Expert: Measures, Rebates, and Really Fast Paybacks

Question: What energy efficiency measures often have the shortest payback, including potential rebates?

Valerie Eacret, ERS, for Zondits

Answer: Here are a few measures with quick paybacks from projects recently crossing our desks:
Compressed air setpoint – Frequently we find that the pressure in compressed air systems is set much higher than necessary. While extensive retrofits might be worth a look, sometimes simply lowering the pressure setpoint is often the easiest place to start as it requires no quotes, contractor management, or other challenges common with typical capital improvement measures. One approach is to lower the pressure on your compressed air system by 1 psi per day and then carefully observe all associated operations, taking care to not impact any super critical equipment at your plant. Once the lower pressure starts noticeably affecting the end use, raise the setpoint by 2 psi so that you will be just above the last known good pressure level. Each 2 psi you’re able to lower your setpoint saves roughly 1% in energy.
RTU enhanced ventilation control – We recently reviewed a project that appears to have a simple payback period of .7 years, with the help of a rebate from the local utility. These controls reduce the fan speed while maintaining necessary airflow to the space in question and can be added to an existing packaged rooftop unit (RTU). The project is about to be installed. Check back here in a few months and we will have results of the actual payback realized.
Right-size your compressor – Oversizing is a common problem with compressors, boilers, chillers, and other equipment. One paper manufacturer we visited recently replaced an oversized compressor that was cycling too frequently with a right-sized, variable speed unit.  Oftentimes oversizing is the result of safety factors getting piled on top of each other in the design phase. With a rebate from the local utility, this project resulted in a one-year payback for the company.
Lighting – Lighting changes often have the biggest cash incentives from your local utility, and some rebate programs will cover up to 100% of the cost of the equipment. This can mean an immediate payment for you if you can do the work as part of regular maintenance with in-house staff!
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